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Dynamics of myofilament sliding studied with a newly developed assay system

Research Project

Project/Area Number 06640876
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 動物生理・代謝
Research InstitutionThe University of Tokyo

Principal Investigator

ISHII Naokata  The University of Tokyo, College of Arts and Sciences, Associate Professor, 教養学部, 助教授 (20151326)

Project Period (FY) 1994 – 1995
Project Status Completed (Fiscal Year 1995)
Budget Amount *help
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1995: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
KeywordsMuscle contraction / Thick filament / myosin / Invitro motility assay system / Force-velocity relation / centrifuge microscope / アクトミオシン / invitro再構成系 / Invitro再構成系 / 軟体動物平滑筋
Research Abstract

To investigate in vitro myofilament sliding in conditions close to those in muscle fibers, a new assay system was developed, in which a polystirene microbead (diameter, 4mum ; specific gravity, 1.3), with a single to a few thick filaments of a molluscan smooth muscle (the anteriour bysus retractor muscle of Mytilus edulis) attached, was made to slide along actin filament arrays (actin cables) in the internodal cell of an alga, mounted on the rotor of a centrifuge microscope. The bead moving along actin cables in the presence of MgATP (5mM) was subjected to centrifugal forces either opposite to the bead movement (positive loads) or in the same direction as the bead movement (negative loads). With positive loads increasing from zero to the maximum isometric force P_0 (15-40pN,20-25C), the velocity of bead movement decreased gradually to zero, exhibiting the hyperbolic force-velocity relation except for load above 0.8 P_0. With further increase of positive loads above P0, the bead was forced to move in the direction of centrifugal force, being eventually detached from actin cables at a load of around 1.4 P_0. These features are very similar to thr force-velocity relation in intact single muscle fibers. With negative loads increasing from zero to a certain value, on the other hand, the velocity of bead movement increased above the maximum unloaded velocity (Vmax, 1.5-3.5mum/s) up to around twice the Vmax, until the bead was eventually detached from actin cables. These results indicate that the present assay system is extremely promising for future combined biochemical and physiological studies on the mechanism of muscle contraction.

Report

(3 results)
  • 1995 Annual Research Report   Final Research Report Summary
  • 1994 Annual Research Report
  • Research Products

    (7 results)

All Other

All Publications (7 results)

  • [Publications] Ishi, N, Tsuchiya, T, and Sugi, H.: "An in vitro motility assay system vetaining steady-state force-velocity characteristics of muscle fibers under positive and negative loads." Proc. Natl. Acad. Sci. USA. (印刷中).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 石井直方: "基礎生物学講座第4巻-動物の行動" 朝倉書店, 178 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Ishii, N., Tsuchiya, T.and Sugi, H.: "An in vitro motility assay system retaining steady-state force-velocity characteristics of muscle fibers under positive and negative loads." Proc.Natl.Acad.Sci.USA. (In press).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Ishii, N.: "Basic Biology, vol.4 : Animal Behavior (In Japanese)" Asakura Shoten pub.1-178 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Ishii,N.,Tsuchiya,T.Sugi,H: "An in vitro motility assay system retaining steady-state force-velocity characteristics of muscle fibers under positive and negative loads" Proc.Natl.Acad.Sci,USA. (印刷中). (1996)

    • Related Report
      1995 Annual Research Report
  • [Publications] 石井直方: "朝倉書店" 基礎生物学講座第4巻-動物の行動. 178 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] N,Ishii,T.Tsuchiya,H.Sugi: "Force-velocity relation in slidinig movemeuts between native thick filaments and actin cables under continuously iucreased load." J.Muscle Res.Cell Motility. (印刷中).

    • Related Report
      1994 Annual Research Report

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Published: 1994-04-01   Modified: 2016-04-21  

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