Updated on 2022/05/25

写真a

 
BANNAI, Hiroko
 
Affiliation
Faculty of Science and Engineering, School of Advanced Science and Engineering
Job title
Professor
Profile
生命の基本単位である細胞は,「細胞膜」という脂質二重膜で囲まれた構造体である.細胞膜は外界と内部環境を隔離するのみならず,細胞内代謝や自己複製に必要な物質の摂取や不要物の排出,細胞内外の情報のやりとりを行うインターフェイスとして機能している.1972年にSingerとNicolsonにより提唱された生体膜モデルによると,細胞膜は脂質二重層とモザイク状に入り混じったタンパク質により構成されている.これらの細胞膜構成要素は流体としての性質を持ち,細胞膜の中をブラウン運動している.この2次元的なブラウン運動を,側方拡散と呼ぶ.熱力学の第二法則に従えば,自由側方拡散により脂質・タンパク質分子は均一に分布するはずである.
しかし実際の細胞膜では,驚くべきことに膜分子の分布は一様ではなく,高密度で特定の分子が局在する領域が多数存在する.これらの領域は,細胞同士の接着や細胞間の信号伝達など,特定の生体機能を集約した「膜機能ドメイン」と呼ぶことのできる構造である.機能ドメインが壊れてしまうと,細胞はその機能を果たすことができず,場合によっては死んでしまう.実際,脳神経疾患の原因の一つは,「シナプス」という機能ドメインの異常によるものである.従って,自由拡散に逆らって膜分子を自己組織化し機能ドメインを形成・維持する分子機構を解明することができれば,生命の本質を理解すると同時に疾患の治療に対して具体的なターゲット分子を提示することも可能になると考えられる.私は「膜分子1分子のダイナミクスを解析することにより,機能ドメインの形成・維持・制御機構を解明する」という方針で研究を行っている.

Concurrent Post

  • Faculty of Science and Engineering   Graduate School of Advanced Science and Engineering

Research Institute

  • 2020
    -
    2022

    理工学術院総合研究所   兼任研究員

Education

  •  
    -
    2000

    The University of Tokyo  

  •  
    -
    2000

    The University of Tokyo   Graduate School, Division of Science  

  •  
    -
    1995

    The University of Tokyo   Faculty of Science   Department of Biological Sciences  

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    The University of Tokyo   Faculty of Science  

Degree

  • The University of Tokyo   Doctor of Science

Research Experience

  • 2019.09
    -
    Now

    Waseda University   Faculty of Science and Engineering Department of Electrical Engineering and Bioscience   Professor

  • 2019.04
    -
    2019.09

    Keio University   School of Medicine, Lab. Neurophysiology   Designated Lecturer

  • 2015.10
    -
    2019.03

    JST   PREST " Innovative technology platforms for integrated single cell analysis"

  • 2013.04
    -
    2016.03

    Nagoya University   Graduate School of Science

  • 2012.04
    -
    2013.03

    RIKEN BSI   JSPD RPD

  • 2007.04
    -
    2012.03

    RIKEN BSI

  • 2005
    -
    2007

    Ecole Normale Superieure, Paris (パリ高等師範学校)ポスドク/日本学術振興会特別研究員PD

  • 2000
    -
    2005

    理化学研究所 研究員

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    御子柴克彦チームリーダー研究室で,量子ドット1分子イメージングによるシナプス可塑性の研究に従事

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    Antoine Triller博士研究室で,抑制性シナプスにおける受容体ダイナミクスの制御機構について研究

  •  
     
     

    御子柴克彦チームリーダー研究室で,細胞内小胞体とIP3受容体神経細胞内トラフィッキングの研究に従事

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Professional Memberships

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    日本神経化学会

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    日本神経科学学会

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    生物物理学会

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    The Japan Neuroscience Society

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    The Biophysical Society of Japan

 

Research Areas

  • Biophysics

  • Neuroscience-general

Research Interests

  • Neuroscience

  • Biophysics

  • 神経細胞生理学

  • epilepsy

  • Quantum dot

  • Single molecule imaging

  • Synaptic plasticity

  • Neurobiology

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Papers

  • Inhibitory Synaptic Transmission Tuned by Ca2+ and Glutamate Through the Control of GABAAR Lateral Diffusion Dynamics

    Bannai H, Niwa F, Sakuragi S, Mikoshiba K

    Dev. Growth Differ.    2020.04  [Refereed]

    DOI

  • Dissection of Local Ca2+ Signals in Cultured Cells by Membrane-targeted Ca2+ Indicators.

    Bannai, H, Hirose, M, Niwa, F, Mikoshiba, K

    J. Vis. Exp.   145   e59246  2020.03  [Refereed]  [Invited]

    DOI

  • Synaptic Function and Neuropathological Disease Revealed by Quantum Dot-Single-Particle Tracking

    Hiroko Bannai, Takafumi Inoue, Matsumi Hirose, Fumihiro Niwa, Katsuhiko Mikoshiba

    Neuromethods     131 - 155  2020  [Refereed]

    DOI

  • Molecular membrane dynamics: Insights into synaptic function and neuropathological disease

    Hiroko Bannai

    Neuroscience Research   129   47 - 56  2018.04  [Refereed]

     View Summary

    The fluid mosaic model states that molecules in the plasma membrane can freely undergo lateral diffusion
    however, in neurons and glia, specific membrane molecules are concentrated in cellular microdomains to overcome the randomizing effects of free diffusion. This specialized distribution of membrane molecules is crucial for various cell functions
    one example is the accumulation of neurotransmitter receptors at the postsynaptic neuronal membrane, which enables efficient synaptic transmission. Quantum dot-single particle tracking (QD-SPT) is a super-resolution imaging technique that uses semiconductor nanocrystal quantum dots as fluorescent probes, and is a powerful tool for analyzing protein and lipid behavior in the plasma membrane. In this article, we review studies implementing QD-SPT in neuroscience research and important data gleaned using this technology. Recent QD-SPT experiments have provided critical insights into the mechanism and physiological relevance of membrane self-organization in neurons and astrocytes in the brain. The mobility of some membrane molecules may become abnormal in cellular models of epilepsy and Alzheimer's disease. Based on these findings, we propose that the behavior of membrane molecules reflects the condition of neurons in pathological disease states.

    DOI PubMed

  • Basal ryanodine receptor activity suppresses autophagic flux

    Tim Vervliet, Isabel Pintelon, Kirsten Welkenhuyzen, Martin D. Bootman, Hiroko Bannai, Katsuhiko Mikoshiba, Wim Martinet, Nael Nadif Kasri, Jan B. Parys, Geert Bultynck

    BIOCHEMICAL PHARMACOLOGY   132   133 - 142  2017.05  [Refereed]

     View Summary

    The inositol 1,4,5-trisphosphate receptors (IP(3)Rs) and intracellular Ca2+ signaling are critically involved in regulating different steps of autophagy, a lysosomal degradation pathway. The ryanodine receptors (RyR), intracellular Ca2+-release channels mainly expressed in excitable cell types including muscle and neurons, have however not yet been extensively studied in relation to autophagy. Yet, aberrant expression and excessive activity of RyRs in these tissues has been implicated in the onset of several diseases including Alzheimer's disease, where impaired autophagy regulation contributes to the pathology. In this study, we determined whether pharmacological RyR inhibition could modulate autophagic flux in ectopic RyR-expressing models, like HEK293 cells and in cell types that endogenously express RyRs, like C2C12 myoblasts and primary hippocampal neurons. Importantly, RyR3 overexpression in HEK293 cells impaired the autophagic flux. Conversely, in all cell models tested, pharmacological inhibition of endogenous or ectopically expressed RyRs, using dantrolene or ryanodine, augmented autophagic flux by increasing lysosomal turn -over (number of autophagosomes and autolysosomes measured as mCherry-LC3 punctaeicell increased from 70.37 +/- 7.81 in control HEK RyR3 cells to 111.18 +/- 7.72 and 98.14 +/- 7.31 after dantrolene and ryanodine treatments, respectively). Moreover, in differentiated C2C12 cells, transmission electron microscopy demonstrated that dantrolene treatment decreased the number of early autophagic vacuoles from 5.9 +/- 2.97 to 1.8 +/- 1.03 per cellular cross section. The modulation of the autophagic flux could be linked to the functional inhibition of RyR channels as both RyR inhibitors efficiently diminished the number of cells showing spontaneous RyR3 activity in the HEK293 cell model (from 41.14% +/- 2.12 in control cells to 18.70% +/- 2.25 and 9.74% +/- 2.67 after dantrolene and ryanodine treatments, respectively). In conclusion, basal RyR-mediated Ca2+-release events suppress autophagic flux at the level of the lysosomes. (C) 2017 Elsevier Inc. All rights reserved.

    DOI PubMed

  • Astroglial Ca2+ signaling is generated by the coordination of IP3R and store-operated Ca2+- channels

    Shigeo Sakuragi, Fumihiro Niwa, Yoichi Oda, Katsuhiko Mikoshiba, Hiroko Bannai

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   486 ( 4 ) 879 - 885  2017.05  [Refereed]

     View Summary

    Astrocytes play key roles in the central nervous system and regulate local blood flow and synaptic transmission via intracellular calcium (Ca2+) signaling. Astrocytic Ca2+ signals are generated by multiple pathways: Ca2+ release from the endoplasmic reticulum (ER) via the inositol 1, 4, 5-trisphosphate receptor (IP3R) and Ca2+ influx through various Ca2+ channels on the plasma membrane. However, the Ca2+ channels involved in astrocytic Ca2+ homeostasis or signaling have not been fully characterized. Here, we demonstrate that spontaneous astrocytic Ca2+ transients in cultured hippocampal astrocytes were induced by cooperation between the Ca2+ release from the ER and the Ca2+ influx through store-operated calcium channels (SOCCs) on the plasma membrane. Ca2+ imaging with plasma membrane targeted GCaMP6f revealed that spontaneous astroglial Ca2+ transients were impaired by pharmacological blockade of not only Ca2+ release through IP(3)Rs, but also Ca2+ influx through SOCCs. Loss of SOCC activity resulted in the depletion of ER Ca2+, suggesting that SOCCs are activated without store depletion in hippocampal astrocytes. Our findings indicate that sustained SOCC activity, together with that of the sarco-endoplasmic reticulum Ca2+-ATPase, contribute to the maintenance of astrocytic Ca2+ store levels, ultimately enabling astrocytic Ca2+ signaling. (C) 2017 Elsevier Inc. All rights reserved.

    DOI PubMed

  • Astrocytic IP(3)Rs: Contribution to Ca2+ Signalling and Hippocampal LTP

    Mark William Sherwood, Misa Arizono, Chihiro Hisatsune, Hiroko Bannai, Etsuko Ebisui, John Lawrence Sherwood, Aude Panatier, Stephane Henri Richard Oliet, Katsuhiko Mikoshiba

    GLIA   65 ( 3 ) 502 - 513  2017.03  [Refereed]

     View Summary

    Astrocytes regulate hippocampal synaptic plasticity by the Ca2+ dependent release of the N-methyl D-aspartate receptor (NMDAR) co-agonist D-serine. Previous evidence indicated that D-serine release would be regulated by the intracellular Ca2+ release channel IP3 receptor (IP3R), however, genetic deletion of IP(3)R2, the putative astrocytic IP3R subtype, had no impact on synaptic plasticity or transmission. Although IP(3)R2 is widely believed to be the only functional IP3R in astrocytes, three IP3R subtypes (1, 2, and 3) have been identified in vertebrates. Therefore, to better understand gliotransmission, we investigated the functionality of IP3R and the contribution of the three IP3R subtypes to Ca2+ signalling. As a proxy for gliotransmission, we found that long-term potentiation (LTP) was impaired by dialyzing astrocytes with the broad IP3R blocker heparin, and rescued by exogenous D-serine, indicating that astrocytic IP(3)Rs regulate D-serine release. To explore which IP3R subtypes are functional in astrocytes, we used pharmacology and two-photon Ca2+ imaging of hippocampal slices from transgenic mice (IP(3)R2(-/-) and IP(3)R2(-/-); 3(-/-)). This approach revealed that underneath IP(3)R2-mediated global Ca2+ events are an overlooked class of IP3R-mediated local events, occurring in astroglial processes. Notably, multiple IP(3)Rs were recruited by high frequency stimulation of the Schaffer collaterals, a classical LTP induction protocol. Together, these findings show the dependence of LTP and gliotransmission on Ca2+ release by astrocytic IP(3)Rs.

    DOI PubMed

  • Dissection of local Ca2+ signals inside cytosol by ER-targeted Ca2+ indicator

    Fumihiro Niwa, Shigeo Sakuragi, Ayana Kobayashi, Shin Takagi, Yoichi Oda, Hiroko Bannai, Katsuhiko Mikoshiba

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   479 ( 1 ) 67 - 73  2016.10  [Refereed]

     View Summary

    Calcium (Ca2+) is a versatile intracellular second messenger that operates in various signaling pathways leading to multiple biological outputs. The diversity of spatiotemporal patterns of Ca2+ signals, generated by the coordination of Ca2+ influx from the extracellular space and Ca2+ release from the intracellular Ca2+ store the endoplasmic reticulum (ER), is considered to underlie the diversity of biological outputs caused by a single signaling molecule. However, such Ca2+ signaling diversity has not been well described because of technical limitations. Here, we describe a new method to report Ca2+ signals at subcellular resolution. We report that OER-GCaMP6f, a genetically encoded Ca2+ indicator (GECI) targeted to the outer ER membrane, can monitor Ca2+ release from the ER at higher spatiotemporal resolution than conventional GCaMP6f. OER-GCaMP6f was used for in vivo Ca2+ imaging of C elegans. We also found that the spontaneous Ca2+ elevation in cultured astrocytes reported by OER-GCaMP6f showed a distinct spatiotemporal pattern from that monitored by plasma membrane-targeted GCaMP6f (Lck-GCaMP6f); less frequent Ca2+ signal was detected by OER-GCaMP6f, in spite of the fact that Ca2+ release from the ER plays important roles in astrocytes. These findings suggest that targeting of GECI5 to the ER outer membrane enables sensitive detection of Ca2+ release from the ER at subcellular resolution, avoiding the diffusion of GECI and Ca2+. Our results indicate that Ca2+ imaging with OER-GCaMP6f in combination with Lck-GCaMP6f can contribute to describing the diversity of Ca2+ signals, by enabling dissection of Ca2+ signals at subcellular resolution. (C) 2016 Elsevier Inc. All rights reserved.

    DOI PubMed

  • [Stabilization of GABAAR synaptic structure by IP3-induced calcium release].

    Niwa F, Bannai H, Mikoshiba K

    Nihon yakurigaku zasshi. Folia pharmacologica Japonica   147 ( 4 ) 184 - 189  2016.04  [Refereed]

    DOI PubMed

  • Bidirectional Control of Synaptic GABA(A)R Clustering by Glutamate and Calcium

    Hiroko Bannai, Fumihiro Niwa, Mark W. Sherwood, Amulya Nidhi Shrivastava, Misa Arizono, Akitoshi Miyamoto, Kotomi Sugiura, Sabine Levi, Antoine Triller, Katsuhiko Mikoshiba

    CELL REPORTS   13 ( 12 ) 2768 - 2780  2015.12  [Refereed]

     View Summary

    GABAergic synaptic transmission regulates brain function by establishing the appropriate excitation-inhibition (E/I) balance in neural circuits. The structure and function of GABAergic synapses are sensitive to destabilization by impinging neurotransmitters. However, signaling mechanisms that promote the restorative homeostatic stabilization of GABAergic synapses remain unknown. Here, by quantum dot single-particle tracking, we characterize a signaling pathway that promotes the stability of GABA(A) receptor (GABA(A)R) postsynaptic organization. Slow metabotropic glutamate receptor signaling activates IP3 receptor-dependent calcium release and protein kinase C to promote GABA(A)R clustering and GABAergic transmission. This GABA(A)R stabilization pathway counteracts the rapid cluster dispersion caused by glutamate-driven NMDA receptor-dependent calcium influx and calcineurin dephosphorylation, including in conditions of pathological glutamate toxicity. These findings show that glutamate activates distinct receptors and spatiotemporal patterns of calcium signaling for opposing control of GABAergic synapses.

    DOI PubMed

  • Spatiotemporal calcium dynamics in single astrocytes and its modulation by neuronal activity

    Yu-Wei Wu, Xiaofang Tang, Misa Arizono, Hiroko Bannai, Pei-Yu Shih, Yulia Dembitskaya, Victor Kazantsev, Mika Tanaka, Shigeyoshi Itohara, Katsuhiko Mikoshiba, Alexey Semyanov

    CELL CALCIUM   55 ( 2 ) 119 - 129  2014.02  [Refereed]

     View Summary

    Astrocytes produce a complex repertoire of Ca2+ events that coordinate their major functions, The principle of Ca2+ events integration in astrocytes, however, is unknown. Here we analyze whole Ca2+ events, which were defined as spatiotemporally interconnected transient Ca2+ increases. Using such analysis in single hippocampal astrocytes in culture and in slices we found that spreads and durations of Ca2+ events follow power law distributions, a fingerprint of scale-free systems. A mathematical model demonstrated that such Ca2+ dynamics can arise from intracellular inositol-3-phosphate diffusion. The power law exponent (a) was decreased by activation of metabotropic glutamate receptors (mGluRs) either by specific receptor agonist or by low frequency stimulation of glutamatergic fibers in hippocampal slices. Decrease in a indicated an increase in proportion of large Ca2+ events. Notably, mGluRs activation did not increase the frequency of whole Ca2+ events. This result suggests that neuronal activity does not trigger new Ca2+ events in astrocytes (detectable by our methods), but modulates the properties of existing ones. Thus, our results provide a new perspective on how astrocyte responds to neuronal activity by changing its Ca2+ dynamics, which might further affect local network by triggering release of gliotransmitters and by modulating local blood flow. (C) 2014 Elsevier Ltd. All rights reserved.

    DOI PubMed

  • Imaging mGluR5 dynamics in astrocytes using quantum dots

    Misa Arizono, Hiroko Bannai, Katsuhiko Mikoshiba

    Current Protocols in Neuroscience   66 ( 66 ) Unit 2.21.  2014  [Refereed]

     View Summary

    This unit describes the method that we have developed to clarify endogenous mGluR5 (metabotropic glutamate receptors 5) dynamics in astrocytes by single-particle tracking using quantum dots (QD-SPT). QD-SPT has been a powerful tool to examine the contribution of neurotransmitter receptor dynamics to synaptic plasticity. Neurotransmitter receptors are also expressed in astrocytes, the most abundant form of glial cell in the brain. mGluR5s, which evoke intracellular Ca2+ signals upon receiving glutamate, contribute to the modulation of synaptic transmission efficacy and local blood flow by astrocytes. QD-SPT has previously revealed that the regulation of the lateral diffusion of mGluR5 on the plasma membrane is important for local Ca2+ signaling in astrocytes. Determining how mGluR5 dynamics are regulated in response to neuronal input would enable a better understanding of neuron-astrocyte communication in future studies. © 2014 by John Wiley and Sons, Inc.

    DOI PubMed

  • Optimal microscopic systems for long-term imaging of intracellular calcium using a ratiometric genetically-encoded calcium indicator

    Akitoshi Miyamoto, Hiroko Bannai, Takayuki Michikawa, Katsuhiko Mikoshiba

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   434 ( 2 ) 252 - 257  2013.05  [Refereed]

     View Summary

    Monitoring the pattern of intracellular Ca2+ signals that control many diverse cellular processes is essential for understanding regulatory mechanisms of cellular functions. Various genetically encoded Ca2+ indicators (GECIs) are used for monitoring intracellular Ca2+ changes under several types of microscope systems. However, it has not yet been explored which microscopic system is ideal for long-term imaging of the spatiotemporal patterns of Ca2+ signals using GECIs. We here compared the Ca2+ signals reported by a fluorescence resonance energy transfer (FRET)-based ratiometric GECI, yellow cameleon 3.60 (YC3.60), stably expressed in DT40 B lymphocytes, using three different imaging systems. These systems included a wide-field fluorescent microscope, a multipoint scanning confocal system, and a single-point scanning confocal system. The degree of photobleaching and the signal-to-noise ratio of YC3.60 in DT40 cells were highly dependent on the fluorescence excitation method, although the total illumination energy was maintained at a constant level within each of the imaging systems. More strikingly, the Ca2+ responses evoked by B-cell antigen receptor stimulation in YC3.60-expressing DT40 cells were different among the imaging systems, and markedly affected by the illumination power used. Our results suggest that optimization of the imaging system, including illumination and acquisition conditions, is crucial for accurate visualization of intracellular Ca2+ signals. (C) 2013 Elsevier Inc. All rights reserved.

    DOI PubMed

  • Type 2 inositol 1,4,5-trisphosphate receptor is predominantly involved in agonist-induced Ca2+ signaling in Bergmann glia

    Sayako Tamamushi, Takeshi Nakamura, Takafumi Inoue, Etsuko Ebisui, Kotomi Sugiura, Hiroko Bannai, Katsuhiko Mikoshiba

    NEUROSCIENCE RESEARCH   74 ( 1 ) 32 - 41  2012.09  [Refereed]

     View Summary

    Ca2+ release via inositol 1,4,5-trisphosphate (IP3) receptors (IP(3)Rs) plays a crucial role in astrocyte functions such as modulation of neuronal activity and regulation of local blood flow in the cerebral cortex and hippocampus. Bergmann glia are unipolar cerebellar astrocytes that release Ca2+ through IP(3)Rs in response to the activation of G(q)-coupled receptors. The composition of the three subtypes of IP3R is a factor that determines the spatiotemporal pattern of Ca2+ release. However, the functional expression of IP3R subtypes and their contribution to Ca2+ release in Bergmann glia remain controversial. In this study, we first characterized the Ca2+ response in Bergmann glia to noradrenaline and histamine stimulation in organotypic cultures of the mouse cerebellum using a Ca2+ indicator, Inverse-Pericam, and found that Bergmann glial processes exhibit a higher agonist-induced Ca2+ indicator response than the soma. Furthermore, we performed Ca2+ imaging using mutant mice lacking each IP3R subtype. This revealed that Bergmann glia lacking type 2 IP3R exhibited reduced responses to noradrenaline or histamine compared with wild-type Bergmann glia and Bergmann glia with other genotypes, suggesting that type 2 IP3R is the major functional IP3R subtype involved in agonist-induced Ca2+ release in Bergmann glia, although types 1 and 3 IP3R could also contribute to rapid agonist-induced [Ca2+](i) elevation in the processes. (C) 2012 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

    DOI PubMed

  • Diffusion Barriers Constrain Receptors at Synapses

    Marianne Renner, Claude Schweizer, Hiroko Bannai, Antoine Triller, Sabine Levi

    PLOS ONE   7 ( 8 ) e43032  2012.08  [Refereed]

     View Summary

    The flux of neurotransmitter receptors in and out of synapses depends on receptor interaction with scaffolding molecules. However, the crowd of transmembrane proteins and the rich cytoskeletal environment may constitute obstacles to the diffusion of receptors within the synapse. To address this question, we studied the membrane diffusion of the gamma-aminobutyric acid type A receptor (GABA(A)R) subunits clustered (gamma 2) or not (alpha 5) at inhibitory synapses in rat hippocampal dissociated neurons. Relative to the extrasynaptic region, gamma 2 and alpha 5 showed reduced diffusion and increased confinement at both inhibitory and excitatory synapses but they dwelled for a short time at excitatory synapses. In contrast, gamma 2 was similar to 3-fold more confined and dwelled similar to 3-fold longer in inhibitory synapses than alpha 5, indicating faster synaptic escape of alpha 5. Furthermore, using a gephyrin dominant-negative approach, we showed that the increased residency time of gamma 2 at inhibitory synapses was due to receptor-scaffold interactions. As shown for GABA(A)R, the excitatory glutamate receptor 2 subunit ( GluA2) of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) had lower mobility in both excitatory and inhibitory synapses but a higher residency time at excitatory synapses. Therefore barriers impose significant diffusion constraints onto receptors at synapses where they accumulate or not. Our data further reveal that the confinement and the dwell time but not the diffusion coefficient report on the synapse specific sorting, trapping and accumulation of receptors.

    DOI PubMed

  • Cooperative and Stochastic Calcium Releases from Multiple Calcium Puff Sites Generate Calcium Microdomains in Intact HeLa Cells

    Hideki Nakamura, Hiroko Bannai, Takafumi Inoue, Takayuki Michikawa, Masaki Sano, Katsuhiko Mikoshiba

    JOURNAL OF BIOLOGICAL CHEMISTRY   287 ( 29 ) 24563 - 24572  2012.07  [Refereed]

     View Summary

    Ca2+ microdomains or locally restricted Ca2+ increases in the cell have recently been reported to regulate many essential physiological events. Ca2+ increases through the inositol 1,4,5-trisphosphate (IP3) receptor (IP3R)/Ca2+ release channels contribute to the formation of a class of such Ca2+ microdomains, which were often observed and referred to as Ca2+ puffs in their isolated states. In this report, we visualized IP3-evoked Ca2+ microdomains in histamine-stimulated intact HeLa cells using a total internal reflection fluorescence microscope, and quantitatively characterized the spatial profile by fitting recorded images to a two-dimensional Gaussian distribution. Ca2+ concentration profiles were marginally spatially anisotropic, with the size increasing linearly even after the amplitude began to decline. We found the event centroid drifted with an apparent diffusion coefficient of 4.20 +/- 0.50 mu m(2)/s, which is significantly larger than those estimated for IP(3)Rs. The sites of maximal Ca2+ increase, rather than initiation or termination sites, were detected repeatedly at the same location. These results indicate that Ca2+ microdomains in intact HeLa cell are generated from spatially distributed multiple IP3R clusters or Ca2+ puff sites, rather than a single IP3R cluster reported in cells loaded with Ca2+ buffers.

    DOI PubMed

  • Receptor-Selective Diffusion Barrier Enhances Sensitivity of Astrocytic Processes to Metabotropic Glutamate Receptor Stimulation

    Misa Arizono, Hiroko Bannai, Kyoko Nakamura, Fumihiro Niwa, Masahiro Enomoto, Toru Matsu-ura, Akitoshi Miyamoto, Mark W. Sherwood, Takeshi Nakamura, Katsuhiko Mikoshiba

    SCIENCE SIGNALING   5 ( 218 ) ra27  2012.04  [Refereed]

     View Summary

    Metabotropic glutamate receptor (mGluR)-dependent calcium ion (Ca2+) signaling in astrocytic processes regulates synaptic transmission and local blood flow essential for brain function. However, because of difficulties in imaging astrocytic processes, the subcellular spatial organization of mGluR-dependent Ca2+ signaling is not well characterized and its regulatory mechanism remains unclear. Using genetically encoded Ca2+ indicators, we showed that despite global stimulation by an mGluR agonist, astrocyte processes intrinsically exhibited a marked enrichment of Ca2+ responses. Immunocytochemistry indicated that these polarized Ca2+ responses could be attributed to increased density of surface mGluR5 on processes relative to the soma. Single-particle tracking of surface mGluR5 dynamics revealed a membrane barrier that blocked the movement of mGluR5 between the processes and the soma. Overexpression of mGluR or expression of its carboxyl terminus enabled diffusion of mGluR5 between the soma and the processes, disrupting the polarization of mGluR5 and of mGluR-dependent Ca2+ signaling. Together, our results demonstrate an mGluR5-selective diffusion barrier between processes and soma that compartmentalized mGluR Ca2+ signaling in astrocytes and may allow control of synaptic and vascular activity in specific subcellular domains.

    DOI PubMed

  • Gephyrin-Independent GABA(A)R Mobility and Clustering during Plasticity

    Fumihiro Niwa, Hiroko Bannai, Misa Arizono, Kazumi Fukatsu, Antoine Triller, Katsuhiko Mikoshiba

    PLOS ONE   7 ( 4 )  2012.04  [Refereed]

     View Summary

    The activity-dependent modulation of GABA-A receptor (GABA(A)R) clustering at synapses controls inhibitory synaptic transmission. Several lines of evidence suggest that gephyrin, an inhibitory synaptic scaffold protein, is a critical factor in the regulation of GABA(A)R clustering during inhibitory synaptic plasticity induced by neuronal excitation. In this study, we tested this hypothesis by studying relative gephyrin dynamics and GABA(A)R declustering during excitatory activity. Surprisingly, we found that gephyrin dispersal is not essential for GABA(A)R declustering during excitatory activity. In cultured hippocampal neurons, quantitative immunocytochemistry showed that the dispersal of synaptic GABA(A)Rs accompanied with neuronal excitation evoked by 4-aminopyridine (4AP) or N-methyl-D-aspartic acid (NMDA) precedes that of gephyrin. Single-particle tracking of quantum dot labeled-GABA(A)Rs revealed that excitation-induced enhancement of GABA(A)R lateral mobility also occurred before the shrinkage of gephyrin clusters. Physical inhibition of GABA(A)R lateral diffusion on the cell surface and inhibition of a Ca2+ dependent phosphatase, calcineurin, completely eliminated the 4AP-induced decrease in gephyrin cluster size, but not the NMDA-induced decrease in cluster size, suggesting the existence of two different mechanisms of gephyrin declustering during activity-dependent plasticity, a GABA(A)R-dependent regulatory mechanism and a GABA(A)R-independent one. Our results also indicate that GABA(A)R mobility and clustering after sustained excitatory activity is independent of gephyrin.

    DOI

  • 3PT206 Regulation of GABAergic synapses by IP_3/Ca^<2+> signaling(The 50th Annual Meeting of the Biophysical Society of Japan)

    Bannai Hiroko, Niwa Fumihiro, Sherwood Mark W., Arizono Misa, Miyamoto Akitoshi, Sugiura Kotomi, Levi Sabine, Triller Antoine, Mikoshiba Katsuhiko

    Seibutsu Butsuri   52   S175 - S176  2012

    DOI CiNii

  • Gephyrin-Independent GABA(A)R Mobility and Clustering during Plasticity.

    Niwa F, Bannai H, Arizono M, Fukatsu K, Triller A, Mikoshiba K

    PloS one   7   e36148  2012  [Refereed]

    DOI PubMed

  • Lateral diffusion of inositol 1,4,5-trisphosphate receptor type 1 in Purkinje cells is regulated by calcium and actin filaments

    Kazumi Fukatsu, Hiroko Bannai, Takafumi Inoue, Katsuhiko Mikoshiba

    JOURNAL OF NEUROCHEMISTRY   114 ( 6 ) 1720 - 1733  2010.09  [Refereed]

     View Summary

    Inositol 1,4,5-trisphosphate receptor type 1 (IP(3)R1) is an intracellular Ca2+ release channel that plays crucial roles in the functions of Purkinje cells. The dynamics of IP(3)R1 on the endoplasmic reticulum membrane and the distribution of IP(3)R1 in neurons are thought to be important for the spatial regulation of Ca2+ release. In this study, we analyzed the lateral diffusion of IP(3)R1 in Purkinje cells in cerebellar slice cultures using fluorescence recovery after photobleaching. In the dendrites of Purkinje cells, IP(3)R1 showed lateral diffusion with an effective diffusion constant of approximately 0.30 mu m2/s, and the diffusion of IP(3)R1 was negatively regulated by actin filaments. We found that actin filaments were also involved in the regulation of IP(3)R1 diffusion in the spine of Purkinje cells. Glutamate or quisqualic acid stimulation, which activates glutamate receptors and leads to a Ca2+ transient in Purkinje cells, decreased the diffusion of IP(3)R1 and increased the density of actin in spines. These findings indicate that the neuronal activity-dependent augmentation of actin contributes to the stabilization of IP(3)R1 in spines.

    DOI PubMed CiNii

  • Activity-Dependent Tuning of Inhibitory Neurotransmission Based on GABA(A)R Diffusion Dynamics

    Hiroko Bannai, Sabine Levi, Claude Schweizer, Takafumi Inoue, Thomas Launey, Victor Racine, Jean-Baptiste Sibarita, Katsuhiko Mikoshiba, Antoine Triller

    NEURON   62 ( 5 ) 670 - 682  2009.06  [Refereed]

     View Summary

    An activity-dependent change in synaptic efficacy is a central tenet in learning, memory, and pathological states of neuronal excitability. The lateral diffusion dynamics of neurotransmitter receptors are one of the important parameters regulating synaptic efficacy. We report here that neuronal activity modifies diffusion properties of type-A GABA receptors (GABA(A)R) in cultured hippocampal neurons: enhanced excitatory synaptic activity decreases the cluster size of GABA(A)Rs and reduces GABAergic mIPSC. Single-particle tracking of the GABA(A)R gamma 2 subunit labeled with quantum dots reveals that the diffusion coefficient and the synaptic confinement domain size of GABA(A)R increases in parallel with neuronal activity, depending on Ca2+ influx and calcineurin activity. These results indicate that GABA(A)R diffusion dynamics are directly linked to rapid and plastic modifications of inhibitory synaptic transmission in response to changes in intracellular Ca2+, concentration. This transient activity-dependent reduction of inhibition would favor the onset of LTP during conditioning.

    DOI PubMed CiNii

  • 4.1N binding regions of inositol 1,4,5-trisphosphate receptor type 1

    K Fukatsu, H Bannai, T Inoue, K Mikoshiba

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   342 ( 2 ) 573 - 576  2006.04  [Refereed]

     View Summary

    Zhang et al. and Maximov et al. [S. Zhang, A. Mizutani, C. Hisatsune, T. Higo, H. Bannai, T. Nakayama, M. Hattori, and K. Mikoshiba, Protein 4.1 N is required for translocation of inositol 1,4,5-trisphosphate receptor type I to the basolateral membrane domain in polarized Madin-Darby canine kidney cells, J. Biol. Chem. 278 (2003) 4048-4056; A. Maximov, T. S. Tang. and I. Bezprozvanny, Association of the type I inositol (1,4,5)-trisphosphate receptor with 4.1 N protein in neurons, Mol. Cell. Neurosci. 22 (2003) 271-283.] reported that 4. 1 N is a binding partner of inositol 1,4,5-trisphosphate receptor type I (IP(3)R1), however the binding site of IP(3)R1 differed: the former determined the C-terminal 14 amino acids of the cytoplasmic tail (CTT14aa) as the binding site.. while the latter assigned another segment, cytoplasmic tail middle 1 (CTM1). To solve this discrepancy, we performed immunoprecipitation and found that both the segments had binding activity to 4.1N. Both segments also interfered the 4.1N-regulated IP3R1 diffusion in neuronal dendrites. However, IP(3)R1 lacking the CTT14aa (IP(3)R1-ACTT14aa) does not bind to 4. 1 N [S. Zhang, A. Mizutani, C. Hisatsune, T. Higo, H. Bannai, T. Nakayama, M. Hattori, and K. Mikoshiba, Protein 4. IN is required for translocation of inositol 1,4,5-trisphosphate receptor type I to the basolateral. membrane domain in polarized Madin-Darby canine kidney cells, J. Biol. Chem. 2 78 (2003) 4048-4056.] and its diffusion constant is larger than that of IP(3)R1 full-length in neuronal dendrites [K. Fukatsu, H. Bannai.. S. Zhang, H. Nakamura, T. Inoue, and K. Mikoshiba, Lateral diffusion of inositol 1,4,5-trisphosphate receptor type I is regulated by actin filaments and 4. 1 N in neuronal dendrites, J. Biol. Chem. 279 (2004) 48976-48982.]. We conclude that both the CTT14aa and CTM1 sequences can bind to 4.1N in peptide fragment forms. However, we propose that the responsible binding site for 4.1 N binding in full-length tetramer form of IP(3)R1 is CTT14aa. (c) 2006 Elsevier Inc. All rights reserved.

    DOI PubMed

  • Imaging the lateral diffusion of membrane molecules with quantum dots

    Hiroko Bannai, Sabine Levi, Claude Schweizer, Maxime Dahan, Antoine Triller

    NATURE PROTOCOLS   1 ( 6 ) 2628 - 2634  2006  [Refereed]

     View Summary

    This protocol describes a sensitive approach to tracking the motion of membrane molecules such as lipids and proteins with molecular resolution in live cells. This technique makes use of fluorescent semiconductor nanocrystals, quantum dots (QDs), as a probe to detect membrane molecules of interest. The photostability and brightness of QDs allow them to be tracked at a single particle level for longer periods than previous fluorophores, such as fluorescent proteins and organic dyes. QDs are bound to the extracellular part of the object to be followed, and their movements can be recorded with a fluorescence microscope equipped with a spectral lamp and a sensitive cooled charge-coupled device camera. The experimental procedure described for neurons below takes about 45 min. This technique is applicable to various cultured cells.

    DOI PubMed

  • Cluster formation of inositol 1,4,5-trisphosphate receptor requires its transition to open state

    Y Tateishi, M Hattori, T Nakayama, M Iwai, H Bannai, T Nakamura, T Michikawa, T Inoue, K Mikoshiba

    JOURNAL OF BIOLOGICAL CHEMISTRY   280 ( 8 ) 6816 - 6822  2005.02  [Refereed]

     View Summary

    The inositol 1,4,5-trisphosphate (IP3) receptor (IPsR) Ca2+ channel plays pivotal roles in many aspects of physiological and pathological events. It was previously reported that IP3R forms clusters on the endoplasmic reticulum when cytosolic Ca2+ concentration ([Ca2+](C)) is elevated. However, the molecular mechanism of IP,R clustering remains largely unknown, and thus its physiological significance is far from clear. In this study we found that the time course of clustering of green fluorescent protein-tagged IP3R type 1 (GFP-IP(3)R1), evoked by IP3-generating agonists, did not correlate with [Ca2+](C) but seemed compatible with cytoplasmic IP3 concentration. IP3 production alone induced GFP-Ip(3)R1 clustering in the absence of a significant increase in [Ca2+](C) but elevated [Ca2+](C) without IP3 production did not. Moreover IP(3)R1 mutants that do not undergo an IP3-induced conformational change failed to form clusters. Thus, IP3R clustering is induced by its IP3-induced conformational change to the open state. We also found that GFP-Ip(3)R1 clusters colocalized with ERp44, a luminal protein of endoplasmic reticulum that inhibits its channel activity. This is the first example of ligand-induced clustering of a ligand-gated channel protein.

    DOI PubMed

  • An RNA-interacting protein, SYNCRIP (heterogeneous nuclear ribonuclear protein Q1/NSAP1) is a component of mRNA granule transported with inositol 1,4,5-trisphosphate receptor type 1 mRNA in neuronal dendrites

    H Bannai, K Fukatsu, A Mizutani, T Natsume, S Iemura, T Ikegami, T Inouie, K Mikoshiba

    JOURNAL OF BIOLOGICAL CHEMISTRY   279 ( 51 ) 53427 - 53434  2004.12  [Refereed]

     View Summary

    mRNA transport and local translation in the neuronal dendrite is implicated in the induction of synaptic plasticity. Recently, we cloned an RNA-interacting protein, SYNCRIP ( heterogeneous nuclear ribonuclear protein Q1/NSAP1), that is suggested to be important for the stabilization of mRNA. We report here that SYNCRIP is a component of mRNA granules in rat hippocampal neurons. SYNCRIP was mainly found at cell bodies, but punctate expression patterns in the proximal dendrite were also seen. Time-lapse analysis in living neurons revealed that the granules labeled with fluorescent protein-tagged SYNCRIP were transported bi-directionally within the dendrite at similar to0.05 mum/s. Treatment of neurons with nocodazole significantly inhibited the movement of green fluorescent protein-SYNCRIP-positive granules, indicating that the transport of SYNCRIP-containing granules is dependent on microtubules. The distribution of SYN-CRIP-containing granules overlapped with that of dendritic RNAs and elongation factor 1alpha. SYNCRIP was also found to be co-transported with green fluorescent protein-tagged human staufen1 and the 3'-untranslated region of inositol 1,4,5-trisphosphate receptor type 1 mRNA. These results suggest that SYNCRIP is transported within the dendrite as a component of mRNA granules and raise the possibility that mRNA turnover in mRNA granules and the regulation of local protein synthesis in neuronal dendrites may involve SYNCRIP.

    DOI PubMed CiNii

  • Lateral diffusion of inositol 1,4,5-trisphosphate receptor type 1 is regulated by actin filaments and 4.1N in neuronal Dendrites

    K Fukatsu, H Bannai, SB Zhang, H Nakamura, T Inoue, K Mikoshiba

    JOURNAL OF BIOLOGICAL CHEMISTRY   279 ( 47 ) 48976 - 48982  2004.11  [Refereed]

     View Summary

    Inositol 1,4,5-trisphosphate receptor type1 (IP(3)R1) plays an important role in neuronal functions; however, the lateral diffusion of IP(3)R1 on the endoplasmic reticulum membrane and its regulation in the living neurons remain unknown. We expressed green fluorescent protein-tagged IP(3)R1 in cultured rat hippocampal neurons and observed the lateral diffusion by the fluorescence recovery after photobleaching technique. IP(3)R1 showed lateral diffusion with an effective diffusion constant of similar to 0.3 mum(2)/s. Depletion of actin filaments increased the diffusion constant of IP(3)R1, suggesting that the diffusion of IP(3)R1 is regulated negatively through actin filaments. We also found that protein 4.1N, which binds to IP(3)R1 and contains an actin-spectrin-binding region, was responsible for this actin regulation of the IP(3)R1 diffusion constant. Overexpression of dominant-negative 4.1N and blockade of 4.1N binding to IP3R1 increased the IP(3)R1 diffusion constant. The diffusion of IP3R type 3 (IP(3)R3), one of the isoforms of IP(3)Rs lacking the binding ability to 4.1N, was not dependent on actin filaments but became dependent on actin filaments after the addition of a 4.1N-binding sequence. These data suggest that 4.1N serves as a linker protein between IP(3)R1 and actin filaments. This actin filament-dependent regulation of IP(3)R1 diffusion may be important for the spatiotemporal regulation of intracellular Ca2+ signaling.

    DOI PubMed CiNii

  • The regulatory domain of the inositol 1,4,5-trisphosphate receptor is necessary to keep the channel domain closed: possible physiological significance of specific cleavage by caspase 3

    T Nakayama, M Hattori, K Uchida, T Nakamura, Y Tateishi, H Bannai, M Iwai, T Michikawa, T Inoue, K Mikoshiba

    BIOCHEMICAL JOURNAL   377 ( 2 ) 299 - 307  2004.01  [Refereed]

     View Summary

    The type 1 mositol 1,4,5-trisphosphate receptor (IP(3)R1) is an intracellular Ca2+ channel protein that plays crucial roles in generating complex Ca2+ signalling patterns. Ip(3)R1 consists of three domains: a ligand-binding domain, a regulatory domain and a channel domain. In order to investigate the function of these domains in its gating machinery and the physiological significance of specific cleavage by caspase 3 that is observed in cells undergoing apoptosis, we utilized various IP(3)R1 constructs tagged with green fluorescent protein (GFP). Expression of GFP-tagged full-length IP(3)R1 or IP(3)R1 lacking the ligand-binding domain in HeLa. and COS-7 cells had little effect on cells' responsiveness to an IP3-generating agonist ATP and Ca2+ leak induced by thapsigargin. On the other hand, in cells expressing the caspase-3-cleaved form (GFP-IP(3)R1-casp) or the channel domain alone (GFP-IP(3)R1-ES), both ATP and thapsigargin failed to induce increase of cytosolic Ca2+ concentration. Interestingly, store-operated (-like) Ca2+ entry was normally observed in these cells, irrespective of thapsigargin pre-treatment. These findings indicate that the Ca2+ stores of cells expressing GFP-IP(3)R1-casp or GFP-IP(3)R1-ES are nearly empty in the resting state and that these proteins continuously leak Ca2+. We therefore propose that the channel domain of IP(3)R1 tends to remain open and that the large regulatory domain of IP(3)R1 is necessary to keep the channel domain closed. Thus cleavage of IP(3)R1 by caspase 3 may contribute to the increased cytosolic Ca2+ concentration often observed in cells undergoing apoptosis. Finally, GFP-IP(3)R1-casp or GFP-IP(3)R1-ES can be used as a novel tool to deplete intracellular Ca2+ stores.

    DOI PubMed CiNii

  • Kinesin dependent, rapid, bi-directional transport of ER sub-compartment in dendrites of hippocampal neurons

    H Bannai, T Inoue, T Nakayama, M Hattori, K Mikoshiba

    JOURNAL OF CELL SCIENCE   117 ( 2 ) 163 - 175  2004.01  [Refereed]

     View Summary

    Although spatially restricted Ca2+ release from the endoplasmic reticulum (ER) through intracellular Ca2+ channels plays important roles in various neuronal activities, the accurate distribution and dynamics of ER in the dendrite of living neurons still remain unknown. To elucidate these, we expressed fluorescent protein-tagged ER proteins in cultured mouse hippocampal neurons, and monitored their movements using time-lapse microscopy. We report here that a sub-compartment of ER forms in relatively large vesicles that are capable, similarly to the reticular ER, of taking up and releasing Ca2+. The vesicular sub-compartment of ER moved rapidly along the dendrites in both anterograde and retrograde directions at a velocity of 0.2-0.3 mum/second. Depletion of microtubules, overexpression of dominant-negative kinesin and kinesin depletion by antisense DNA reduced the number and velocity of the moving vesicles, suggesting that kinesin may drive the transport of the vesicular sub-compartment of ER along microtubules in the dendrite. Rapid transport of the Ca2+-releasable sub-compartment of ER might contribute to rapid supply of fresh ER proteins to the distal part of the dendrite, or to the spatial regulation of intracellular Ca2+ signaling.

    DOI PubMed CiNii

  • Protein 4.1N is required for translocation of inositol 1,4,5-trisphosphate receptor type 1 to the basolateral membrane domain in polarized Madin-Darby canine kidney cells

    SB Zhang, A Mizutani, C Hisatsune, T Higo, H Bannai, T Nakayama, M Hattori, K Mikoshiba

    JOURNAL OF BIOLOGICAL CHEMISTRY   278 ( 6 ) 4048 - 4056  2003.02  [Refereed]

     View Summary

    Protein 4.1N was identified as a binding molecule for the C-terminal cytoplasmic tail of inositol 1,4,5-trisphosphate receptor type 1 (IP(3)R1) using a yeast two-hybrid system. 4.1N and IP(3)R1 associate in both subconfluent and confluent Madin-Darby canine kidney (MDCK) cells, a well studied tight polarized epithelial cell line. In subconfluent MDCK cells, 4.1N is distributed in the cytoplasm and the nucleus; IP(3)R1 is localized in the cytoplasm. In confluent MDCK cells, both 4.1N and IP(3)R1 are predominantly translocated to the basolateral membrane domain, whereas 4.1R, the prototypical homologue of 4.1N, is localized at the tight junctions (Mattagajasingh, S. N., Huang, S. C., Hartenstein, J. S., and Benz, E. J., Jr. (2000) J. Biol. Chem. 275, 3057330585), and other endoplasmic reticulum marker proteins are still present in the cytoplasm. Moreover, the 4.1N-binding region of IP(3)R1 is necessary and sufficient for the localization of IP(3)R1 at the basolateral membrane domain. A fragment of the IP(3)R1-binding region of 4.1N blocks the localization of co-expressed IP3R1 at the basolateral membrane domain. These data indicate that 4.1N is required for IP3R1 translocation to the basolateral membrane domain in polarized MDCK cells.

    DOI PubMed CiNii

  • Calcium regulation of microtubule sliding in reactivated sea urchin sperm flagella

    H Bannai, M Yoshimura, K Takahashi, C Shingyoji

    JOURNAL OF CELL SCIENCE   113 ( 5 ) 831 - 839  2000.03  [Refereed]

     View Summary

    The changes in the bending pattern of flagella induced by an increased intracellular Ca2+ concentration are caused by changes in the pattern and velocity of microtubule sliding. However, the mechanism by which Ca2+ regulates microtubule sliding in flagella has been unclear To elucidate it, we studied the effects of Ca2+ on microtubule sliding in reactivated sea urchin sperm flagella that were beating under imposed head vibration, We found that the maximum microtubule sliding velocity obtainable by imposed vibration, which was about 170-180 rad/second in the presence of 250 mu M MgATP and &lt;10(-9) M Ca2+, was decreased by 10(-6)-10(-5) M Ca2+ by about 15-20%. Similar decrease of the sliding velocity was observed at 54 and 27 mu M MgATP. The Ca2+-induced decrease of the sliding velocity was due mainly to a decrease in the reverse bend angle. When the plane of beat was artificially rotated by rotating the plane of vibration of the pipette that held the sperm head, the asymmetric bending pattern also rotated at 10(-5) M Ca2+ as well as at &lt;10(-9) M Ca2+. The rotation of the bending pattern was observed at MgATP higher than 54 mu M (similar to 100 mu M ATP). These results indicate that the Ca2+-induced decrease of the sliding velocity is mediated by a rotatable component or components (probably the central pair) at high MgATP, but is not due to specific dynein arms on particular doublets, We further investigated the effects of a mild trypsin treatment and of trifluoperazine on the Ca2+-induced decrease in sliding velocity. Axonemes treated for 3 minutes with a low concentration (0.1 mu g/ml) of trypsin beat with a more symmetrical waveform than before the treatment. Also, their microtubule sliding velocity and reverse bend angle were not affected by high Ca2+ concentrations. Trifluoperazine (25-50 mu M) had no effect on the decrease of the sliding velocity in beating flagella at 10(-5) M Ca2+. However, the flagella that had been 'quiescent' at 10(-4) M Ca2+ resumed asymmetrical beating following an application of 10-50 mu M trifluoperazine. In such beating flagella, both the sliding velocity and the reverse bend angle mere close to their respective values at 10(-5) M Ca2+. Trypsin treatment induced a similar recovery of beating in quiescent flagella at 10(-4) M Ca2+, albeit with a more symmetrical waveform. These results provide first evidence that, at least at ATP concentrations higher than similar to 100 mu M, 10(-6)-10(-5) M Ca2+ decreases the maximum sliding velocity of microtubules in beating flagella through a trypsin-sensitive regulatory mechanism which possibly involves the central pair apparatus. They also suggest that calmodulin may be associated with the mechanism underlying flagellar quiescence induced by 10(-4) M Ca2+.

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Misc

  • 3SDA-01 Watch the "membrane protein behavior" to know the "intracellular signaling pathway"(Cutting-Edge Optical Imaging Approaches and Raman Micro-Spectroscopy Pioneering Bio-Physics,Symposium,The 52th Annual Meeting of the Biophysical Society of Japan(B

    Bannai Hiroko, Niwa Fumihiro, Triller Antoine, Mikoshiba Katsuhiko

    Biophysics   54 ( 1 )  2014.08

    CiNii

  • 3SBA-01 Origin-dependent opposite effect of Ca^<2+> on the regulation of inhibitory GABA_A receptor diffusion dynamics : a single molecule study(3SBA Cutting-edge optical imaging approach to neuroscience -From single molecule to in vivo-,Symposium,The 51t

    Bannai Hiroko, Niwa Fumihiro, Triller Antoine, Mikoshiba Katsuhiko

    Biophysics   53 ( 1 )  2013.09

    CiNii

  • Diffusion Barrier Compartmentalizes Signals in Astrocytes

    ARIZONO Misa, BANNAI Hiroko, NIWA Fumihiro, MIKOSHIBA Katsuhiko

    Seibutsu Butsuri   53 ( 2 ) 105 - 106  2013.03

    DOI CiNii

  • Biophysics Opens up the Future of Brain Science

    BANNAI Hiroko

    Seibutsu Butsuri   52 ( 2 ) 112 - 113  2012.03

    CiNii

  • 1SH-05 Membrane molecular dynamics supporting brain functions revealed by single molecule imaging in live cells(1SH Visualizing proteins in action -frontiers in biomolecular imaging-,The 49th Annual Meeting of the Biophysical Society of Japan)

    Bannai Hiroko, Arizono Misa, Niwa Fumihiro, Mikoshiba Katsuhiko

    Biophysics   51 ( 1 )  2011.08

    CiNii

  • 神経伝達物質受容体の側方拡散が抑制性シナプス伝達を決める

    坂内 博子

    神経化学   49 ( 1 ) 25 - 33  2010.03

    CiNii

  • Analysis of the dynamics of membrane molecules by single-molecule imaging technique with quantum dots

    坂内 博子, 御子柴 克彦

    生体の科学   61 ( 2 ) 194 - 200  2010.03

    DOI CiNii

  • Lateral diffusion of inositol 1,4,5-trisphosphate receptor type 1 in Purkinje cells is regulated by calcium and actin filaments.

    Fukatsu K, Bannai H, InoueT, Mikoshiba K

    J. Neurochem.   114 ( 6 ) 1720 - 1733  2010

    DOI PubMed CiNii

  • 3SP7-02 Approach to synaptic plasticity by single molecule imaging(3SP7 Cutting-edge approach to studying neural circuits,The 47th Annual Meeting of the Biophysical Society of Japan)

    Bannai Hiroko

    Biophysics   49 ( 1 )  2009.09

    CiNii

  • Activity-Dependent Tuning of Inhibitory Neurotransmission Based on GABAAR Diffusion Dynamics

    Bannai H, Levi S, Schweizer C, Inoue T, Launey T, Racine V, Sibarita JB, Mikoshiba K, Triller A

    Neuron   62 ( 5 ) 670 - 682  2009

    DOI PubMed CiNii

  • Activity-Dependent Tuning of Inhibitory Neurotransmission Based on GABAAR Diffusion Dynamics

    Bannai H, Levi S, Schweizer C, Inoue T, Launey T, Racine V, Sibarita JB, Mikoshiba K, Triller A

    Neuron   62 ( 5 ) 670 - 682  2009

    DOI PubMed CiNii

  • Homeostatic regulation of synaptic GlyR numbers driven by lateral diffusion

    Sabine Levi, Claude Schweizer, Hiroko Bannai, Olivier Pascual, Cecile Charrier, Antoine Triller

    NEURON   59 ( 2 ) 261 - 273  2008.07

     View Summary

    In the spinal cord, most inhibitory synapses have a mixed glycine-GABA phenotype. Using a pharmacological approach, we report an NMDAR activity-dependent regulation of the mobility of GlyRs but not GABA(A)Rs at inhibitory synapses in cultured rat spinal cord neurons. The NMDAR-induced decrease in GlyR lateral diffusion was correlated with an increase in receptor cluster number and glycinergic mlPSC amplitude. Changes in GlyR diffusion properties occurred rapidly and before the changes in the number of synaptic receptors. Regulation of synaptic GlyR content occurred without change in the amount of gephyrin. Moreover, NMDAR-dependent regulation of GlyR lateral diffusion required calcium influx and calcium release from stores. Therefore, excitation may increase GlyR levels at synapses by a calcium-mediated increase in postsynaptic GlyR trapping involving regulation of receptor-scaffold interactions. This provides a mechanism for a rapid homeostatic regulation of the inhibitory glycinergic component at mixed glycine-GABA synapses in response to increased NMDA excitatory transmission.

    DOI PubMed CiNii

  • 4.1N binding regions of inositol 1,4,5-trisphosphate receptor type 1.

    Fukatsu K, Bannai H, Inoue T, Mikoshiba K

    Biochem Biophys Res Commun.   342 ( 2 ) 573 - 576  2006

    DOI PubMed CiNii

  • Imaging the lateral diffusion of membrane molecules with quantum dots.

    Bannai H, Lévi S, Schweizer C, Dahan M, Triller A

    Nat Protoc.   1 ( 6 ) 2628-34.  2006

    DOI

  • 4.1N binding regions of inositol 1,4,5-trisphosphate receptor type 1.

    Fukatsu K, Bannai H, Inoue T, Mikoshiba K

    Biochem Biophys Res Commun.   342 ( 2 ) 573 - 576  2006

    DOI PubMed CiNii

  • Imaging the lateral diffusion of membrane molecules with quantum dots.

    Bannai H, Lévi S, Schweizer C, Dahan M, Triller A

    Nat Protoc.   1 ( 6 ) 2628 - 34  2006

    DOI

  • Cluster formation of inositol 1,4,5-trisphosphate receptor requires its transition to open state.

    Tateishi Y, Hattori M, Nakayama T, Iwai M, Bannai H, Nakamura T, Michikawa T, Inoue T, Mikoshiba K

    J Biol Chem.   280 ( 8 ) 6816 - 6822  2005

    DOI PubMed CiNii

  • Cluster formation of inositol 1,4,5-trisphosphate receptor requires its transition to open state.

    Tateishi Y, Hattori M, Nakayama T, Iwai M, Bannai H, Nakamura T, Michikawa T, Inoue T, Mikoshiba K

    J Biol Chem.   280 ( 8 ) 6816 - 6822  2005

    DOI PubMed CiNii

  • 2P280 Lateral diffusion of IP_3 receptor typel is regulated by actin filaments and 4.1N

    Fukatsu K, Bannai H, Zhang S, Nakamura H, Inoue T, Mikoshiba K

    Biophysics   44 ( 1 )  2004.11

    CiNii

  • 3P225 An RN A-interacting protein, SYNCRIP (hnRNP Q1/NSAP1), is a component of mRNA granules transported on microtubules in neuronal dendrites

    Bannai H, Fukatsu K, Mizutani A, Natsume T, Iemura S, Ikegami T, Inoue T, Mikoshiba K

    Biophysics   44 ( 1 )  2004.11

    CiNii

  • The regulatory domain of the inositol 1,4,5-trisphosphate receptor is necessary to keep the channel domain closed: possible physiological significance of specific cleavage by caspase 3.

    Nakayama T, Hattori M, Uchida K, Nakamura T, Tateishi Y, Bannai H, Iwai M, Michikawa T, Inoue T, Mikoshiba K

    Biochem J.   377 ( 2 ) 299 - 307  2004

    DOI PubMed CiNii

  • Kinesin dependent, rapid, bi-directional transport of ER sub-compartment in dendrites of hippocampal neurons.

    Bannai H, Inoue T, Nakayama T, Hattori M, Mikoshiba K

    J Cell Sci   117 ( 2 ) 163 - 175  2004

    DOI PubMed CiNii

  • Lateral diffusion of inositol 1,4,5-trisphosphate receptor type 1 is regulated by actin filaments and 4.1N in neuronal dendrites.

    Fukatsu K, Bannai H, Zhang S, Nakamura H, Inoue T, Mikoshiba K

    J Biol Chem.   279 ( 47 ) 48976 - 48982  2004

    DOI PubMed CiNii

  • An RNA-interacting protein, SYNCRIP (heterogeneous nuclear ribonuclear protein Q1/NSAP1) is a component of mRNA granule transported with inositol 1,4,5-trisphosphate receptor type 1 mRNA in neuronal dendrites.

    Bannai H, Fukatsu K, Mizutani A, Natsume T, Iemura S, Ikegami T, Inoue T, Mikoshiba K

    J Biol Chem.   279 ( 51 ) 53427 - 53434  2004

    DOI PubMed CiNii

  • The regulatory domain of the inositol 1,4,5-trisphosphate receptor is necessary to keep the channel domain closed: possible physiological significance of specific cleavage by caspase 3.

    Nakayama T, Hattori M, Uchida K, Nakamura T, Tateishi Y, Bannai H, Iwai M, Michikawa T, Inoue T, Mikoshiba K

    Biochem J.   377 ( 2 ) 299 - 307  2004

    DOI PubMed CiNii

  • Kinesin dependent, rapid, bi-directional transport of ER sub-compartment in dendrites of hippocampal neurons.

    Bannai H, Inoue T, Nakayama T, Hattori M, Mikoshiba K

    J Cell Sci   117 ( 2 ) 163 - 175  2004

    DOI PubMed CiNii

  • Lateral diffusion of inositol 1,4,5-trisphosphate receptor type 1 is regulated by actin filaments and 4.1N in neuronal dendrites.

    Fukatsu K, Bannai H, Zhang S, Nakamura H, Inoue T, Mikoshiba K

    J Biol Chem.   279 ( 47 ) 48976 - 48982  2004

    DOI PubMed CiNii

  • An RNA-interacting protein, SYNCRIP (heterogeneous nuclear ribonuclear protein Q1/NSAP1) is a component of mRNA granule transported with inositol 1,4,5-trisphosphate receptor type 1 mRNA in neuronal dendrites.

    Bannai H, Fukatsu K, Mizutani A, Natsume T, Iemura S, Ikegami T, Inoue T, Mikoshiba K

    J Biol Chem.   279 ( 51 ) 53427 - 53434  2004

    DOI PubMed CiNii

  • The mechanism of intracellular transport and the physiological role of the vesicular sub-compartment of ER in the neuronal dendrite

    Bannai H, Inoue T, Nakayama T, Hattori M, Mikoshiba K

    Biophysics   43 ( 1 )  2003.08

    CiNii

  • The regulatory mechanism of IP_3receptor dynamics by cytoskeleton

    Fukatsu K, Bannai H, Zhang S, Inoue T, Mikoshiba K

    Biophysics   43 ( 1 )  2003.08

    CiNii

  • Protein 4.1N is required for translocation of inositol 1,4,5-trisphosphate receptor type 1 to the basolateral membrane domain in polarized Madin-Darby canine kidney cells.

    Zhang S, Mizutani A, Hisatsune C, Higo T, Bannai H, Nakayama T, Hattori M, Mikoshiba K

    J Biol Chem.   278 ( 6 ) 4048 - 4056  2003

    DOI PubMed CiNii

  • Protein 4.1N is required for translocation of inositol 1,4,5-trisphosphate receptor type 1 to the basolateral membrane domain in polarized Madin-Darby canine kidney cells.

    Zhang S, Mizutani A, Hisatsune C, Higo T, Bannai H, Nakayama T, Hattori M, Mikoshiba K

    J Biol Chem.   278 ( 6 ) 4048 - 4056  2003

    DOI PubMed CiNii

  • イノシトール1,4,5-三リン酸受容体のクラスター形成の分子機構

    立石陽子, 服部光治, 坂内博子, 岩井美和子, 内田敬子, 中村健, 道川貴章, 井上貴文, 御子柴克彦

    日本分子生物学会年会プログラム・講演要旨集   26th  2003

    J-GLOBAL

  • 2E1615 Microtubule dependent fast, bi-directional movement of vesicular endoplasmic reticulum in neuronal dendrites.

    Bannai H, Inoue T, Nakayama T, Hattori M, Mikoshiba K

    Biophysics   42 ( 2 )  2002.10

    CiNii

  • Calcium regulation of microtubule sliding in reactivated sea urchin sperm flagella.

    Bannai H, Yoshimura M, Takahashi K, Shingyoji C

    J Cell Sci.   113 ( 5 ) 831 - 9  2000

  • Calcium regulation of microtubule sliding in reactivated sea urchin sperm flagella.

    Bannai H, Yoshimura M, Takahashi K, Shingyoji C

    J Cell Sci.   113 ( 5 ) 831 - 9  2000

▼display all

Awards

  • JSPS prize

    2017.12   JSPS   Single Molecule Imaging Approach to Mechanisms Underlying Brain Functions

    Winner: Hiroko BANNAI

  • Japan Neuroscience Society Young Investigator Award

    2013.06   Japan Neuroscience Society  

    Winner: Hiroko BANNAI

  • RIKEN SPF Poster Prize

    2010.01   RIKEN  

    Winner: Hiroko BANNAI

  • 日本生物物理学会 若手奨励賞

    2008.12  

Research Projects

  • 神経変性疾患におけるシンギュラリティ現象の解析と分子機構の解明

    文部科学省  科学研究費助成事業 新学術領域研究

    Project Year :

    2018.06
    -
    2023.03
     

    坂内 博子

  • Regulation of synaptic and non-synaptic functions by extracellular scaffolding proteins

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Specially Promoted Research

    Project Year :

    2020.07
    -
    2025.03
     

  • Regulation of synaptic and non-synaptic functions by extracellular scaffolding proteins

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

    Project Year :

    2020.04
    -
    2025.03
     

  • 外界刺激へ応答するCblnファミリーを介した脳回路制御機構

    日本学術振興会  科学研究費助成事業 基盤研究(B)

    Project Year :

    2020.04
    -
    2023.03
     

    石田 綾, 石川 理子, 坂内 博子

  • 膜受容体の流動性とシグナル伝達の関係性から見た揮発性麻酔薬作用機序の解明

    日本学術振興会  科学研究費助成事業 基盤研究(C)

    Project Year :

    2019.04
    -
    2022.03
     

    小野 純一郎, 樺山 一哉, 坂内 博子, 鈴木 辰吾

  • 脳細胞カルシウムシグナルの空間的分離とデコーディング

    日本学術振興会  科学研究費助成事業 基盤研究(C)

    Project Year :

    2016.04
    -
    2020.03
     

    坂内 博子

     View Summary

    細胞内カルシウムイオン(Ca2+)の増減「Ca2+シグナル」は、細胞の外界からの情報を適切な生理応答へと変換する役割を担う、普遍的な細胞内シグナルである。しかし、同じCa2+という伝達物質を用いて複数のメッセージを生命暗号としてコードし、多様な生理機能の誘導を可能にする機構については未解明の点が多い。先行研究において我々は、「Local Ca2+センサー」を作成し、従来法では判別できなかったカルシウムシグナルの由来(細胞内からの放出か、細胞外からの流入か)を特定し、Ca2+シグナルの多様性を記述するための新解析法を確立している。今年度は、同一細胞で2カ所同時でのCa2+シグナル測定を可能にするために、波長の異なるセンサーを利用して細胞膜とER膜の同時カルシウムイメージングの技術を確立した。細胞膜に標的したRCaMP2 (Lck-RCaMP2)とER膜に標的したGCaMP6f (OER-GCaMP6f)を同一細胞で、同時に観察できる測定系を確立した。広い視野をもつCMOSカメラとイメージスプリッティング光学系の組み合わせにより、時空間的に高い解像度で、Ca2+シグナルの発生パターンを記録することができた。この測定系を用いてHeLa細胞のHistamine刺激に対する応答を観察したところ、細胞膜に標的したセンサーは長期間持続したCa2+シグナルを示すのに対し、ER膜標的センサーは速やかなCa2+シグナルの低下を示した。この結果は、同じ刺激をうけても、Ca2+シグナルは細胞の局所ドメインごとに異なるを示すということを意味している。

  • Single-molecule imaging approach to the mechanism of the cytotoxitity of aggregated proteins

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

    Project Year :

    2017.04
    -
    2019.03
     

  • Project to create international glial researcher network: mainly focusing on Japan-Germany research exchange

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

    Project Year :

    2015.11
    -
    2018.03
     

    IKENAKA Kazuhiro, ITO Kei, UEKI Takatoshi, OHKI Kenichi, KATO Takahiro, KANEMARU Kazunori, SHIMIZU Takeshi, TAKEBAYASHI Hirohide, TANAKA Kenji, HASHIOTO Kohichi, YAMAZAKI Yoshihiko, INOUE Kazuhide, OKABE Shigeo, OZAKI Norio, KANBA Shigenobu, KIRA Junichi, KOHSAKA Shinichi, FUKUYAMA Hidenao, BANNAI Hiroko, NAKASHIMA Kinichi, IMAI Hiroo, MATSUI Ko, TACHIKAWA Masanori, KAKEGAWA Wataru

     View Summary

    We Glia Assembly communicated with Glial Heterogeneity (sponsored by DFG, program name SPP1757, project leader Dr. Frank Kirchhoff) and organized the international research consortium, called “YoungGlia”. The purpose of this framework is to stimulate mutual exchange visits of young researchers of glial research. The collaborative research between Japan and Germany will be carried out by the young researchers.The collaboration must be approved by the principle investigators on both sides but the original proposal and execution of the research itself must be done by the young researchers. According to the above basic concept, we selected 11 research pairs at 1st (FY2015) and 2nd (FY2016) YoungGlia and supported their international collaborations for 1-2 years. We organized 3rd YoungGlia (FY2017) and all funded pairs presented their achievements. In addition, at the 3rd YoungGlia, we invited Canadian and American groups and expanded our partnership beyond Japan-Germany communication.

  • グリア細胞カルシウムシグナルの進化的意義の解明

    日本学術振興会  科学研究費助成事業 新学術領域研究(研究領域提案型)

    Project Year :

    2014.04
    -
    2016.03
     

    坂内 博子

     View Summary

    グリア細胞の存在は多くの生物種で知られているが,ほ乳類以外の動物において神経系で,脳機能の制御に積極的に関わるか否かは明らかにされていない.本研究では,が透明で遺伝子組換え動物の作成が容易であり,逃避行動に関わる神経回路に関する知見が豊富なゼブラフィッシュの利点を生かし,グリア細胞におけるカルシウムシグナルが個体の行動制御を司る可能性を明らかにした。細胞膜に標的したGCaMP6f(LCK-GCaMP6f)をGFAPプロモータ制御下で発現するゼブラフィッシュを用いて受精後3-7日稚魚脳のin vivoイメージングを行い,視蓋,後脳,脊髄のグリア細胞で自発的なカルシウムシグナルが存在することを確認した.また、逃避行動を誘起する聴覚刺激(500 Hz)を与えたところ,後脳のグリア細胞では自発的カルシウムシグナルとは異なる,より長く広範囲に広がるカルシウムシグナルが観察された.この結果は、魚類でも神経活動に伴ってグリア細胞の活動が誘起されることを示唆している.また、Young gliaの枠組みで、デュッセルフ大学のGriemsmaan博士と共同で、げっ歯類アストロサイトAMPA受容体の1分子イメージング実験を行った。さらに、ER標的型のGCaMP6fを開発し、げっ歯類海馬アストロサイトにおいて自発的カルシウムシグナルイメージングを行ったところ、実はERからのカルシウム放出よりもカルシウム流入の方が多いことがわかった(Niwa et al. 2016). このカルシウム流入は正体はStore operated Ca2+ channel (SOCC)を介しておこっており、海馬アストロサイトではERが枯渇しない状態でもSOCCが恒常的に活性化され、ERのカルシウム量を一定に保つことに貢献していることが示された(Sakuragi et al. 2017)。

  • ゼブラフィッシュをモデルとしたグリア細胞の生理的役割と進化的意義の研究

    日本学術振興会  科学研究費助成事業 研究活動スタート支援

    Project Year :

    2013.08
    -
    2015.03
     

    坂内 博子

     View Summary

    ほ乳類の脳においてグリア細胞の一種アストロサイトは,神経細胞の生存や発達機能発現のためのサポートに加えて,カルシウムシグナル依存的にシナプス伝達効率や局所脳血流の制御を司る.グリア細胞の存在は多くの生物種で知られているが,ほ乳類以外の動物において,グリア細胞が成熟した神経系において脳機能の制御に積極的に関わるか否かはほとんど明らかにされていない.本研究は,ゼブラフィッシュをモデル生物として,ほ乳類のアストロサイト同様魚類のグリア細胞が,成熟した神経系においてカルシウムシグナル依存的に神経伝達や動物の行動を制御できるかを検討し,グリア細胞の役割の進化的意義を探ることを目的とする.本年度は計画通り,ゼブラフィッシュグリア細胞におけるカルシウムシグナル検出法の確立を行った.名古屋大学の小田洋一教授,谷本昌志助教の指導のもと,逆行性ラベルやサカナのライブイメージング等,基本となる手技を獲得した.遺伝子コード型カルシウム指示薬(GPCI)をグリア細胞特異的に発現するゼブラフィッシュ系統を作成するために,東島眞一准教授(生理学研究所)および川上浩一教授(遺伝学研究所)との共同研究を開始した.サカナの遺伝子組み換えに必要なベクターを入手し,本研究に特化したGPCIの改変を行った.また,本研究のもう一つの柱は,光学顕微鏡の分解能を越えた「超解像STED顕微鏡」を利用したシナプスーグリア細胞相互作用形態の観察である.そのために,STED顕微鏡の専門家であるボルドー大学のValentin Nagerl教授を招聘し,ゼブラフィッシュの脳イメージングに適用するためのアドバイスを得た.

  • Studies on the physiological or pathological neuronal regulation based on the receptor dynamics and calcium signals

    Ministry of Education, Culture, Sports, Science and Technology  Grants-in-Aid for Scientific Research(若手研究(B))

    Project Year :

    2008
    -
    2011
     

    Hiroko BANNAI

     View Summary

    The mobility of the neurotransmitter receptors on the plasma membrane is one of the factors determining the efficacy of synaptic transmission. In this study, we found that the increase in GABA_A receptor lateral diffusion, which is induced by Ca^<2+> influx from the extracellular space and subsequent the activation of calcineurin, is the starting point of inhibitory synaptic plasticity. Our result also suggested the possibility that Ca^<2+> release from the intracellular Ca^<2+> store contributes to the inhibition of GABA_A receptor lateral diffusion through protein phosphorylation.

  • 量子ドット1分子イメージングによるシナプス可塑性の分子機構の解明

    基礎科学特別研究員研究費

    Project Year :

    2007
    -
    2010
     

  • IP_3/Ca^<2+>シグナリングの空間的制御機構の研究

    文部科学省  科学研究費補助金(若手研究(B))

    Project Year :

    2004
    -
    2006
     

    坂内 博子

     View Summary

    IP_3受容体は細胞内小胞体からのカルシウム放出を担うチャネルの一つであり,その機能は時間的空間的に厳密に制御されている.IP_3受容体の局在がカルシウム放出の空間的制御に寄与していると予想されているが,カルシウムシグナルとIP_3受容体の局在を関連づけた研究はこれまで行われていない.MDCK細胞のIP_3受容体タイプ1は,sub-confluent状態では細胞全体のER膜上に存在しconfluent状態ではER膜から離れて細胞膜近傍に局在することが知られているので,IP_3受容体の位置変化にともなって"量子的IP_3依存的カルシウム放出"(Ca^<2+> puff)の位置もsub-confluentとconfluentで変化するか否かを,全反射顕微鏡を利用したカルシウムイメージング法で調べた.実験初期の段階で,MDCK細胞はconfluencyに関わらず自発的なカルシウム流入を常に行っていることを見いだした.このカルシウム流入は細胞外カルシウム濃度依存的であり,Ca^<2+> puffと同様量子的に観察された.Ca^<2+> puffをこの量子的カルシウム流入と区別するために,本研究では細胞外カルシウム非存在下でCa^<2+> puffの測定を行った.カルシウム指示薬にFluo-4,細胞膜のラベルにoctadecyl rhodamine B chlorideを用いることにより,Ca^<2+> puffの細胞の位置情報が得られる実験系を確立した.現在実験で得られたデータをもとに細胞膜とCa^<2+> puffがおこる場所との関係を解析し,sub-confluentとconfluentで差があるかどうかを統計的に検討している.また,MDCK細胞における自発的な量子的カルシウム流入は新しい知見であり,腎臓におけるカルシウムの再吸収に関わる可能性が考えられる.このためカルシウム流入を担うチャネルを同定するために,薬理学的実験を行っている.

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Presentations

  • Calcium-dependent tuning of inhibitory neurotransmission based on GABAAR diffusion dynamics.

    Gordon Research Conference in Calcium Signalling (Lucca, Italy) 

    Presentation date: 2009

  • La dynamique des recepteurs détermine la transmission synaptique (受容体ダイナミクスがシナプス伝達を決める)

    la 26eme Rencontre Scientifique Francophone de Tokyo 

    Presentation date: 2009

  • Approach to synaptic plasticity by single molecule imaging

    第47回日本生物物理学会年会 (シンポウジウム Cutting-edge approach to studying neural circuits) 

    Presentation date: 2009

  • 神経活動依存的なGABAA受容体の側方拡散制御

    第31回日本神経科学大会(東京) 

    Presentation date: 2008

  • 量子ドット1分子イメージングによる抑制性シナプス制御機構の解明

    第46回日本生物物理学会年会(第4回若手奨励賞招待講演) 

    Presentation date: 2008

  • IP3受容体の細胞内トラフィッキング

    Neuro2007(Neuro2007/(株)ニコンインステック 共催セミナー) 

    Presentation date: 2007

  • Synaptic activity dependent-regulation of the lateral diffusion of GABAA receptors

    Federation of European Neuroscience Societies 5 Biennial Forum (Vienna, Austria) 

    Presentation date: 2006

  • RNA結合タンパク質SYNCRIPはmRNA granuleの構成要素である

    第77回日本生化学会大会(横浜) 

    Presentation date: 2004

  • 神経細胞樹状突起における微小管依存的なRNA結合タンパク質SYNCRIPの輸送 -mRNA顆粒の構成要素として-

    第42回日本生物物理学会年会(京都) 

    Presentation date: 2004

  • 神経細胞樹状突起におけるvesicle状小胞体の輸送メカニズムと機能の解析

    第41回日本生物物理学会年会(新潟) 

    Presentation date: 2003

  • Kinesin dependent, rapid, bi-directional transport of ER sub-compartment in dendrites of hippocampal neurons.

    Calcium Oscillations: Molecular Mechanisms and Medical Implications of an Extraordinarily Versatile Cell Signal -Joint Symposium of Karolinska Institute and Japan Science and Technology Agency- (Stockholm, Sweden) 

    Presentation date: 2003

  • 神経細胞樹状突起における高速,両方向性,微小管依存的な小胞体輸送

    第40回日本生物物理学会年会(名古屋) 

    Presentation date: 2002

  • Microtubule dependent fast, bidirectional movement of ER vesicles in dendrites of mouse hippocampal neuron.

    46th annual meeting of the Biophysical Society (San Francisco, USA) 

    Presentation date: 2002

  • Effect of mild trypsin treatment on calcium-induced decrease of microtubule sliding velocity in reactivated sea urchin sperm flagella

    第70回日本動物学会年会(山形) 

    Presentation date: 1999

  • Calcium-induced decrease in microtubule sliding velocity in reactivated sea urchin sperm flagella beating with imposed frequencies

    38th Annual Meeting of ASCB (San Francisco, USA) 

    Presentation date: 1998

  • Effect of increased viscosity on the velocity of microtubule sliding in reactivated sea urchin sperm flagella under imposed head vibration

    第68回日本動物学会年会(奈良) 

    Presentation date: 1997

  • Effect of calcium on the velocity of microtubule sliding in reactivated sea urchin sperm flagella under imposed head vibration.

    International Symposium on Molecular Motors (Tsukuba, Japan) 

    Presentation date: 1996

  • Effect of calcium on the velocity of microtubule sliding in reactivated sea urchin sperm flagella under imposed head vibration

    第67回日本動物学会年会(札幌) 

    Presentation date: 1996

  • Effect of calcium and viscosity on the velocity of microtubule sliding in reactivated sea urchin sperm flagella under imposed head vibration.

    第34回日本生物物理学会年会(筑波) 

    Presentation date: 1996

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Specific Research

  • 1分子動態解析によるアルツハイマー病発症メカニズムの解明

    2021  

     View Summary

    本研究では1分子イメージングでアルツハイマー病特異的に膜分子動態異常を明らかにすることを目指している。今年度は、アルツハイマー病におこる細胞レベルの病態であるタウ凝集を人為的に作り出す技術を開発した。また、マルチカラー1分子イメージングのための新規ラベル技術、解析技術の開発を行った。さらに、慶應義塾大学医学部との共同研究で、アルツハイマー病に関連するタウ変異を持つiPS細胞の研究を開始した。本研究の成果の一部を3件の国際学会、2件の国内学会の招待講演で発表した。

 

Syllabus

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Teaching Experience

  • 「生物学実験」理学部1年生

    名古屋大学  

  • G30 experiment (1st year)

    Nagoya Univ  

  • G30 Lab Training (3rd year)

    Nagoya Univ.  

  • 「基礎生物学演習」生命理学科2年生

    名古屋大学  

  • 「生理学I」生命理学科3年生

    名古屋大学  

 

Committee Memberships

  • 2020.10
    -
    Now

    Science Council of Japan  Members

  • 2020.05
    -
    Now

    The Biophysical Society of Japan  Website Committee

  • 2020.01
    -
    Now

    The Japan Neuroscience Society  Future Planning Committee, Outreach Committee

  • 2017.06
    -
    2019.05

    日本生物物理学会  理事

  • 2015.01
    -
    2018.12

    日本生物物理学会  分野別専門委員(グリア細胞)

  • 2012.01
    -
    2012.12

    日本生物物理学会  分野別専門委員

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