Researchers Database

kasuya gou

    PhysiologyIntegrativePhysiology Research Associate
Last Updated :2021/10/19

Researcher Information


Research funding number

  • 80845115


J-Global ID

Research Interests

  • Electrophysiology   Structural biology   Electron micriscope   Ion channels   

Research Areas

  • Life sciences / Clinical pharmacy
  • Life sciences / Physiology
  • Life sciences / Biophysics
  • Life sciences / Structural biochemistry

Academic & Professional Experience

  • 2019/04 - Today  自治医医科大学医学部生理学講座 統合生理学部門助教


  •        - 2018/03  東京大学大学院  理学系研究科  生物科学専攻博士課程

Published Papers

  • Yoshiaki Kise, Go Kasuya, Hiroyuki H. Okamoto, Daichi Yamanouchi, Kan Kobayashi, Tsukasa Kusakizako, Tomohiro Nishizawa, Koichi Nakajo, Osamu Nureki
    Nature 0028-0836 2021/09 [Refereed]
    AbstractModulation of voltage-gated potassium (Kv) channels by auxiliary subunits is central to the physiological function of channels in the brain and heart1,2. Native Kv4 tetrameric channels form macromolecular ternary complexes with two auxiliary β-subunits—intracellular Kv channel-interacting proteins (KChIPs) and transmembrane dipeptidyl peptidase-related proteins (DPPs)—to evoke rapidly activating and inactivating A-type currents, which prevent the backpropagation of action potentials1–5. However, the modulatory mechanisms of Kv4 channel complexes remain largely unknown. Here we report cryo-electron microscopy structures of the Kv4.2–DPP6S–KChIP1 dodecamer complex, the Kv4.2–KChIP1 and Kv4.2–DPP6S octamer complexes, and Kv4.2 alone. The structure of the Kv4.2–KChIP1 complex reveals that the intracellular N terminus of Kv4.2 interacts with its C terminus that extends from the S6 gating helix of the neighbouring Kv4.2 subunit. KChIP1 captures both the N and the C terminus of Kv4.2. In consequence, KChIP1 would prevent N-type inactivation and stabilize the S6 conformation to modulate gating of the S6 helices within the tetramer. By contrast, unlike the reported auxiliary subunits of voltage-gated channel complexes, DPP6S interacts with the S1 and S2 helices of the Kv4.2 voltage-sensing domain, which suggests that DPP6S stabilizes the conformation of the S1–S2 helices. DPP6S may therefore accelerate the voltage-dependent movement of the S4 helices. KChIP1 and DPP6S do not directly interact with each other in the Kv4.2–KChIP1–DPP6S ternary complex. Thus, our data suggest that two distinct modes of modulation contribute in an additive manner to evoke A-type currents from the native Kv4 macromolecular complex.
  • Kazumasa Oda, Takashi Nomura, Takanori Nakane, Keitaro Yamashita, Keiichi Inoue, Shota Ito, Johannes Vierock, Kunio Hirata, Andrés D Maturana, Kota Katayama, Tatsuya Ikuta, Itsuki Ishigami, Tamaki Izume, Rie Umeda, Ryuun Eguma, Satomi Oishi, Go Kasuya, Takafumi Kato, Tsukasa Kusakizako, Wataru Shihoya, Hiroto Shimada, Tomoyuki Takatsuji, Mizuki Takemoto, Reiya Taniguchi, Atsuhiro Tomita, Ryoki Nakamura, Masahiro Fukuda, Hirotake Miyauchi, Yongchan Lee, Eriko Nango, Rie Tanaka, Tomoyuki Tanaka, Michihiro Sugahara, Tetsunari Kimura, Tatsuro Shimamura, Takaaki Fujiwara, Yasuaki Yamanaka, Shigeki Owada, Yasumasa Joti, Kensuke Tono, Ryuichiro Ishitani, Shigehiko Hayashi, Hideki Kandori, Peter Hegemann, So Iwata, Minoru Kubo, Tomohiro Nishizawa, Osamu Nureki
    eLife 10 2021/03 [Refereed][Not invited]
    Channelrhodopsins (ChRs) are microbial light-gated ion channels utilized in optogenetics to control neural activity with light . Light absorption causes retinal chromophore isomerization and subsequent protein conformational changes visualized as optically distinguished intermediates, coupled with channel opening and closing. However, the detailed molecular events underlying channel gating remain unknown. We performed time-resolved serial femtosecond crystallographic analyses of ChR by using an X-ray free electron laser, which revealed conformational changes following photoactivation. The isomerized retinal adopts a twisted conformation and shifts toward the putative internal proton donor residues, consequently inducing an outward shift of TM3, as well as a local deformation in TM7. These early conformational changes in the pore-forming helices should be the triggers that lead to opening of the ion conducting pore.
  • Cryo-EM structure of the volume-regulated anion channel LRRC8D isoform identifies features important for substrate permeation
    R. Nakamura, T. Numata, G. Kasuya, T. Yokoyama, T. Nishizawa, T. Kusakizako, T. Kato, T. Hagino, N. Dohmae, M. Inoue, K. Watanabe, H. Ichijo, M. Kikkawa, M. Shirouzu, T. J. Jentsch, R. Ishitani, Y. Okada, O. Nureki
    Commun Biol. 2020 [Refereed][Not invited]
  • Kazuki Kato, Hiroshi Nishimasu, Daisuke Oikawa, Seiichi Hirano, Hisato Hirano, Go Kasuya, Ryuichiro Ishitani, Fuminori Tokunaga, Osamu Nureki
    Nature communications 9 (1) 4424 - 4424 2018/10 [Refereed][Not invited]
    ENPP1 (Ecto-nucleotide pyrophosphatase phosphodiesterase 1), a type II transmembrane glycoprotein, hydrolyzes ATP to produce AMP and diphosphate, thereby inhibiting bone mineralization. A recent study showed that ENPP1 also preferentially hydrolyzes 2'3'-cGAMP (cyclic GMP-AMP) but not its linkage isomer 3'3'-cGAMP, and negatively regulates the cGAS-STING pathway in the innate immune system. Here, we present the high-resolution crystal structures of ENPP1 in complex with 3'3'-cGAMP and the reaction intermediate pA(3',5')pG. The structures revealed that the adenine and guanine bases of the dinucleotides are recognized by nucleotide- and guanine-pockets, respectively. Furthermore, the structures indicate that 2'3'-cGAMP, but not 3'3'-cGAMP, binds to the active site in a conformation suitable for catalysis, thereby explaining the specific degradation of 2'3'-cGAMP by ENPP1. Our findings provide insights into how ENPP1 hydrolyzes both ATP and cGAMP to participate in the two distinct biological processes.
  • Go Kasuya, Takanori Nakane, Takeshi Yokoyama, Yanyan Jia, Masato Inoue, Kengo Watanabe, Ryoki Nakamura, Tomohiro Nishizawa, Tsukasa Kusakizako, Akihisa Tsutsumi, Haruaki Yanagisawa, Naoshi Dohmae, Motoyuki Hattori, Hidenori Ichijo, Zhiqiang Yan, Masahide Kikkawa, Mikako Shirouzu, Ryuichiro Ishitani, Osamu Nureki
    Nature Structural & Molecular Biology Springer Nature America, Inc 2018/09 [Refereed][Not invited]
  • Go Kasuya, Toshiaki Yamaura, Xiao-Bo Ma, Ryoki Nakamura, Mizuki Takemoto, Hiromitsu Nagumo, Eiichi Tanaka, Naoshi Dohmae, Takanori Nakane, Ye Yu, Ryuichiro Ishitani, Osamu Matsuzaki, Motoyuki Hattori, Osamu Nureki
    NATURE COMMUNICATIONS 8 2041-1723 2017/10 [Refereed][Not invited]
    P2X receptors are non-selective cation channels gated by extracellular ATP, and the P2X7 receptor subtype plays a crucial role in the immune and nervous systems. Altered expression and dysfunctions of P2X7 receptors caused by genetic deletions, mutations, and polymorphic variations have been linked to various diseases, such as rheumatoid arthritis and hypertension. Despite the availability of crystal structures of P2X receptors, the mechanism of competitive antagonist action for P2X receptors remains controversial. Here, we determine the crystal structure of the chicken P2X7 receptor in complex with the competitive P2X antagonist, TNP-ATP. The structure reveals an expanded, incompletely activated conformation of the channel, and identified the unique recognition manner of TNP-ATP, which is distinct from that observed in the previously determined human P2X3 receptor structure. A structure-based computational analysis furnishes mechanistic insights into the TNP-ATP-dependent inhibition. Our work provides structural insights into the functional mechanism of the P2X competitive antagonist.
  • Go Kasuya, Yuichiro Fujiwara, Hisao Tsukamoto, Satoshi Morinaga, Satoshi Ryu, Kazushige Touhara, Ryuichiro Ishitani, Yuji Furutani, Motoyuki Hattori, Osamu Nureki
    Scientific Reports 7 2045-2322 2017/03 [Refereed][Not invited]
    P2X receptors are trimeric ATP-gated cation channels involved in diverse physiological processes, ranging from muscle contraction to nociception. Despite the recent structure determination of the ATP-bound P2X receptors, the molecular mechanism of the nucleotide base specificity has remained elusive. Here, we present the crystal structure of zebrafish P2X4 in complex with a weak affinity agonist, CTP, together with structure-based electrophysiological and spectroscopic analyses. The CTP-bound structure revealed a hydrogen bond, between the cytosine base and the side chain of the basic residue in the agonist binding site, which mediates the weak but significant affinity for CTP. The cytosine base is further recognized by two main chain atoms, as in the ATP-bound structure, but their bond lengths seem to be extended in the CTP-bound structure, also possibly contributing to the weaker affinity for CTP over ATP. This work provides the structural insights for the nucleotide base specificity of P2X receptors.
  • Go Kasuya, Masahiro Hiraizumi, Andres D. Maturana, Kaoru Kumazaki, Yuichiro Fujiwara, Keihong Liu, Yoshiko Nakada-Nakura, So Iwata, Keisuke Tsukada, Tomotaka Komori, Sotaro Uemura, Yuhei Goto, Takanori Nakane, Mizuki Takemoto, Hideaki E. Kato, Keitaro Yamashita, Miki Wada, Koichi Ito, Ryuichiro Ishitani, Motoyuki Hattori, Osamu Nureki
    CELL RESEARCH 26 (12) 1288 - 1301 1001-0602 2016/12 [Refereed][Not invited]
    Ca2+ release from the sarcoplasmic reticulum (SR) and endoplasmic reticulum (ER) is crucial for muscle contraction, cell growth, apoptosis, learning and memory. The trimeric intracellular cation (TRIC) channels were recently identified as cation channels balancing the SR and ER membrane potentials, and are implicated in Ca2+ signaling and homeostasis. Here we present the crystal structures of prokaryotic TRIC channels in the closed state and structure-based functional analyses of prokaryotic and eukaryotic TRIC channels. Each trimer subunit consists of seven transmembrane (TM) helices with two inverted repeated regions. The electrophysiological, biochemical and biophysical analyses revealed that TRIC channels possess an ion-conducting pore within each subunit, and that the trimer formation contributes to the stability of the protein. The symmetrically related TM2 and TM5 helices are kinked at the conserved glycine clusters, and these kinks are important for the channel activity. Furthermore, the kinks of the TM2 and TM5 helices generate lateral fenestrations at each subunit interface. Unexpectedly, these lateral fenestrations are occupied with lipid molecules. This study provides the structural and functional framework for the molecular mechanism of this ion channel superfamily.
  • Yuichi Minato, Shiho Suzuki, Tomoaki Hara, Yutaka Kofuku, Go Kasuya, Yuichiro Fujiwara, Shunsuke Igarashi, Ei-ichiro Suzuki, Osamu Nureki, Motoyuki Hattori, Takumi Ueda, Ichio Shimada
    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 113 (17) 4741 - 4746 0027-8424 2016/04 [Refereed][Not invited]
    Ligand-gated ion channels are partially activated by their ligands, resulting in currents lower than the currents evoked by the physiological full agonists. In the case of P2X purinergic receptors, a cation-selective pore in the transmembrane region expands upon ATP binding to the extracellular ATP-binding site, and the currents evoked by a, alpha-methylene ATP are lower than the currents evoked by ATP. However, the mechanism underlying the partial activation of the P2X receptors is unknown although the crystal structures of zebrafish P2X(4) receptor in the apo and ATP-bound states are available. Here, we observed the NMR signals from M339 and M351, which were introduced in the transmembrane region, and the endogenous alanine and methionine residues of the zebrafish P2X(4) purinergic receptor in the apo, ATP-bound, and alpha,beta-methylene ATP-bound states. Our NMR analyses revealed that, in the alpha,beta-methylene ATP-bound state, M339, M351, and the residues that connect the ATP-binding site and the transmembrane region, M325 and A330, exist in conformational equilibrium between closed and open conformations, with slower exchange rates than the chemical shift difference (< 100 s(-1)), suggesting that the small population of the open conformation causes the partial activation in this state. Our NMR analyses also revealed that the transmembrane region adopts the open conformation in the state bound to the inhibitor trinitrophenyl-ATP, and thus the antagonism is due to the closure of ion pathways, except for the pore in the transmembrane region: i.e., the lateral cation access in the extracellular region.
  • Go Kasuya, Yuichiro Fujiwara, Mizuki Takemoto, Naoshi Dohmae, Yoshiko Nakada-Nakura, Ryuichiro Ishitani, Motoyuki Hattori, Osamu Nureki
    CELL REPORTS 14 (4) 932 - 944 2211-1247 2016/02 [Refereed][Not invited]
    P2X receptors are trimeric ATP-gated cation channels involved in physiological processes ranging widely from neurotransmission to pain and taste signal transduction. The modulation of the channel gating, including that bydivalent cations, contributes to these diverse physiological functions of P2X receptors. Here, we report the crystal structure of an invertebrate P2X receptor from the Gulf Coast tick Amblyomma maculatum in the presence of ATP and Zn2+ ion, together with electrophysiological and computational analyses. The structure revealed two distinct metal binding sites, M1 and M2, in the extracellular region. The M1 site, located at the trimer interface, is responsible for Zn2+ potentiation by facilitating the structural change of the extracellular domain for pore opening. In contrast, the M2 site, coupled with the ATP binding site, might contribute to regulation by Mg2+. Overall, our work provides structural insights into the divalent cation modulations of P2X receptors.
  • Tomohiro Nishizawa, Satomi Kita, Andrés D. Maturana, Noritaka Furuya, Kunio Hirata, Go Kasuya, Satoshi Ogasawara, Naoshi Dohmae, Takahiro Iwamoto, Ryuichiro Ishitani, Osamu Nureki
    Science 341 (6142) 168 - 172 1095-9203 2013 [Refereed][Not invited]
    Ca2+/cation antiporters catalyze the exchange of Ca2+ with various cations across biological membranes to regulate cytosolic calcium levels. The recently reported structure of a prokaryotic Na+/Ca 2+ exchanger (NCX-Mj) revealed its overall architecture in an outward-facing state. Here, we report the crystal structure of a H +/Ca2+ exchanger from Archaeoglobus fulgidus (CAX-Af) in the two representatives of the inward-facing conformation at 2.3 Å resolution. The structures suggested Ca2+ or H+ binds to the cation-binding site mutually exclusively. Structural comparison of CAX-Af with NCX-Mj revealed that the first and sixth transmembrane helices alternately create hydrophilic cavities on the intra- and extracellular sides. The structures and functional analyses provide insight into the mechanism of how the inward- to outward-facing state transition is triggered by the Ca2+ and H+ binding.

Conference Activities & Talks


  • Structural insights into divalent cation modulations and ligand specificity of ATP-gated P2X receptor channels
    Fujiwara Y, Kasuya G, Hattori M, Nureki O  Journal of Physiological Sciences  66-  (Supplement1)  S66  2016  [Refereed][Not invited]

Research Grants & Projects

  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    Date (from‐to) : 2020/04 -2023/03 
    Author : 糟谷 豪
  • 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
    Date (from‐to) : 2019/08 -2021/03 
    Author : 糟谷 豪
  • p53依存的なオートファジー関わる膜輸送体DRAMの機能構造解析
    日本学術振興会:科学研究費助成事業 特別研究員奨励費
    Date (from‐to) : 2017/04 -2019/03 
    Author : 糟谷 豪
    オートファジーは、進化的に保存された細胞内自己分解経路である。外界からの各種刺激によりオートファジーが誘導されると、細胞質中でオートファゴソームと呼ばれる隔離膜が形成され、細胞内の不要産物を包み込む。その後、オートファゴソームとリソソームが融合しオートリソソームが形成され、不要産物が分解される。DRAMはガン抑制遺伝子のp53により活性化されるリソソーム膜タンパク質である。DRAMの活性化はリソソームの酸性化や透過性亢進を引き起こし、オートリソソーム形成とそれに伴うアポトーシスを誘導する。しかしながら、DRAMの分子機構については、他のタンパク質との配列相同性から金属イオンを輸送するトランスポーターであることが示唆されているに留まっており、その構造基盤は不明であった。 本研究では現在までに、ある哺乳類由来DRAM1が精製、結晶化に適していることを見出した。そして、結晶化能の向上を目指し、野生型よりも安定性の高い改変コンストラクトを作成することに成功した。他方で、他生物種由来のDRAM1についても、各種哺乳類からクローニングを行い、うち1種について精製、結晶化を行うことに成功した。今後は、結晶化および発現コンストラクトの詳細な条件検討を行い、最適化を目指す。 本年度はまた、これまでDRAMの構造解析に取り組んできた経験と技術基盤を生かし細胞外ATPを受容するリガンド依存性チャネルであるP2X受容体に関して、その活性阻害機構の構造基盤の解明を目指し、チキン由来P2X7受容体についてその競合阻害剤であるTNP-ATPが結合した状態での立体構造決定に成功した。そして、得られた構造情報に基づいた電気生理学および分子動力学的解析を行うことで、TNP-ATP依存的なP2X受容体の阻害機構を解明するとともに、この内容をまとめた論文をNature communications誌に発表した。

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