Evidence for the Essential Role of Myosin Subfragment-2 in the ATP-Dependent Actin-Myosin Sliding in Muscle Contraction

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Author(s)

Abstract

The role of myosin subfragment-2 (myosin S-2) in muscle contraction was studied by using an in vitro motility assay system in which the ATP-dependent sliding between myosin-coated polystyrene beads and actin filament arrays (actin cables) of giant algal cells were recorded under constant external loads provided with a centrifuge microscope. With antibody to myosin S-2 below 0.3 mg/ml, the maximum “isometric” force generated by myosin molecules on the bead decreased markedly, but the unloaded bead-sliding velocity along actin cables did not change appreciably, indicating a decrease in the number of myosin molecules interacting with actin scables. The antibody at 0.3-1.5 mg/ml decreased not only the maximum isometric force, but also the unloaded bead-sliding velocity in a dose-dependent manner. With the antibody at 1.5-3 mg/ml, the beads eventually stopped moving to remain attached to actin cables. These beads could be readily detached from actin cables with very small centrifugal forces, indicating very weak actin-myosin linkages. The antibody had no effect on rigor actin myosin linkages fromed before the antibody application. These results are consistent with the view that myosin S-2 plays an essential role in muscle contraction.

Journal

  • The Japanese Journal of Physiology

    The Japanese Journal of Physiology 48(5), 383-387, 1998-10

    THE PHYSIOLOGICAL SOCIETY OF JAPAN

References:  14

Codes

  • NII Article ID (NAID)
    10008305472
  • NII NACSIS-CAT ID (NCID)
    AA00691224
  • Text Lang
    ENG
  • Article Type
    ART
  • ISSN
    0021521X
  • NDL Article ID
    4615131
  • NDL Source Classification
    ZS8(科学技術--医学--解剖学・生理学・生化学)
  • NDL Call No.
    Z53-D40
  • Data Source
    CJP  NDL  J-STAGE 
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