Influence of an actin-modulating protein from smooth muscle on actin-myosin interaction

FEBS Lett. 1984 Nov 19;177(2):209-16. doi: 10.1016/0014-5793(84)81285-5.

Abstract

The actin-modulating protein from pig stomach smooth muscle (PSAM) which reduces the average filament length has two opposite effects on the interaction of actin with skeletal muscle myosin: (1) stimulation of both the Mg2+-ATPase activity and superprecipitation at low KCl concentrations, and (2) inhibition of these two interrelated processes at an ionic strength close to physiological. Both stimulation and inhibition were Ca2+-dependent, reflecting the requirement for Ca2+ for the interaction of the modulator with actin. With acto-subfragment-1, only inhibition of the actin-activated ATPase was observed. Possible implications of these effects for studies on the regulation of smooth muscle contraction are discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism*
  • Actomyosin / metabolism*
  • Animals
  • Cytoskeletal Proteins*
  • Cytoskeleton / ultrastructure
  • Kinetics
  • Microscopy, Electron
  • Muscle, Smooth / physiology*
  • Muscles / metabolism
  • Myosins / metabolism*
  • Proteins / pharmacology*
  • Rabbits
  • Stomach / physiology
  • Swine

Substances

  • Actins
  • Cytoskeletal Proteins
  • Proteins
  • actin-modulating proteins
  • Actomyosin
  • Myosins