Kamata, Tetsuji



School of Medicine, Department of Anatomy (Shinanomachi)


Research Associate/Assistant Professor/Instructor

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Academic Degrees 【 Display / hide

  • M.D., Keio University, Dissertation, 1991.02

Licenses and Qualifications 【 Display / hide

  • 医師免許, 1984.06


Research Areas 【 Display / hide

  • Life Science / Cell biology

  • Life Science / Hematology and medical oncology

Research Keywords 【 Display / hide

  • integrin

  • cell adhesion

  • platelet

Research Themes 【 Display / hide

  • Structural mechanisms of integrin activation, 



Books 【 Display / hide

  • Paolo Gresele, Valentin Fuster, Jose A. Lopez, Clive P. Page, Jos Vermylen, eds. PLATELETS IN HEMATOLOGIC AND CARDIOVASCULAR DISORDERS: A CLINICAL HANDBOOK

    Yasuo Ikeda, Yumiko Matsubara, Kamata Tetsuji, Cambridge University Press, 2008

    Scope: Platelet immunology: structure, functions, and polymorphisms of membrane glycoproteins

  • 血栓症ナビゲータ

    鎌田 徹治, メディカルレビュー社, 2005

    Scope: 細胞外基質

  • 池田康夫編集「血小板生物学」

    鎌田 徹治, メディカルレビュー社, 2004

    Scope: 血小板インテグリン−β1インテグリン

  • 最新内科学体系21

    池田康夫,鎌田 徹治, 中山書店, 1992

    Scope: 先天性血小板機能異常症

Papers 【 Display / hide

  • Electron microscopy shows that binding of monoclonal antibody PT25-2 primes integrin αIIbβ3 for ligand binding

    Nesi D., Bush M., Coller B.S., Li J., Kamata T., Handa M., Walz T.

    Blood Advances (Blood Advances)  5 ( 7 ) 1781 - 1790 2021.03

    ISSN  24739529

     View Summary

    The murine monoclonal antibody (mAb) PT25-2 induces aIIbβ3 to bind ligand and initiate platelet aggregation. The underlying mechanism is unclear, because previous mutagenesis studies suggested that PT25-2 binds to the aIIb b propeller, a site distant from the Arg-Gly-Asp-binding pocket. To elucidate the mechanism, we studied the aIIbb3-PT25-2 Fab complex by negative-stain and cryo-electron microscopy (EM). We found that PT25-2 binding results in aIIbb3 partially exposing multiple ligand-induced binding site epitopes and adopting extended conformations without swing-out of the b3 hybrid domain. The cryo-EM structure showed PT25-2 binding to the aIIb residues identified by mutagenesis but also to 2 additional regions. Overlay of the cryo-EM structure with the bent aIIbb3 crystal structure showed that binding of PT25-2 creates clashes with the aIIb calf-1/calf-2 domains, suggesting that PT25-2 selectively binds to partially or fully extended receptor conformations and prevents a return to its bent conformation. Kinetic studies of the binding of PT25-2 compared with mAbs 10E5 and 7E3 support this hypothesis. We conclude that PT25-2 induces aIIbb3 ligand binding by binding to extended conformations and by preventing the interactions between the aIIb and b3 leg domains and subsequently the bI and b3 leg domains required for the bent-closed conformation.

  • Epitope mapping for monoclonal antibody reveals the activation mechanism for αVβ3 integrin

    Kamata T, Handa M, Takakuwa S, Sato Y, Kawai Y, Ikeda Y, Aiso S

    PLoS One 8 ( 6 ) e66096 2013

    Research paper (scientific journal), Joint Work, Accepted

  • Structural requirements for activation in alphaIIb beta3 integrin

    Kamata T, Handa M, Ito S, Sato Y, Ohtani T, Kawai Y, Ikeda Y, Aiso S

    J Biol Chem 285 ( 49 ) 38428 - 38437 2010

    Research paper (scientific journal), Joint Work, Accepted

  • Key interactions in integrin ectodomain responsible for global conformational change detected by elastic network normal-mode analysis

    Matsumoto A, Kamata T, Takagi J, Iwasaki K, Yura K

    Biophys J 95 ( 6 ) 2895 - 2908 2008

    Research paper (scientific journal), Joint Work, Accepted

  • 血小板β1インテグリン


    医学のあゆみ  2005

    Research paper (scientific journal), Single Work, Accepted

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Presentations 【 Display / hide

  • Divalent cations define the structural requirement for activation in αIIbβ3 integrin

    Kamata T, Handa M, Kawai Y, Ikeda Y, Aiso S

    The 54th ASH Annual Meeting and Exposition (Atlanta, GA, USA) , 


  • Separation of the two extracellular tails is required to propagate activation signals initiated in the cytoplasmic tails of αIIbβ3 integrin

    Kamata T, Handa M, Kawai Y, Ikeda Y, Aiso S

    The 23rd Congress of the International Society on Thrombosis and Haemostasis (Kyoto, Japan) , 


  • Regulatory Role of the Extracellular α-tail/β-tail Interaction in αIIbβ3 Integrin Activation

    Kamata T, Handa M, Kawai Y, Ikeda Y, Aiso S

    The 52nd American Society of Hematology Annual Meeting and Exposition (Orlando, Florida, USA) , 


  • 血小板 αIIbβ3 インテグリンの活性化メカニズム


    第17回日本血液代替物学会年次大会シンポジウム (熊本市国際交流会館,熊本市) , 


  • 細胞外α-tail/β-tail の結合はαIIbβ3インテグリンの活性化を制御する

    鎌田徹治,半田 誠,川合陽子,池田康夫,相磯貞和

    第72回日本血液学会学術集会一般口演 (パシフィコ横浜,横浜市西区みなとみらい) , 


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Courses Taught 【 Display / hide











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