Regulation of Ca2+-activated tension in limulus striated muscle

W. G.L. Kerrick, L. L. Bolles

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Skinned tail and leg muscle fibers of the limulus were used to study the mechanism of Ca2+ regulation of contraction. Although a Ca2+-sensitive 31,000 dalton protein phosphorylation could be observed in the presence of [γ-32P] ATP no such phosphorylation occurred in the presence of [γ-32P] ITP. Ca2+-activated tension occurred equally as well in ATP and ITP. For this reason we eliminated the possibility that a Ca2+-sensitive myosin light chain kinase/phosphatase system is the mechanism responsible for the Ca2+-activated tension. Other agents known to affect a myosin light chain kinase/phosphatase system showed negative results (ATPγS, trifluoperazine, catalytic subunit of the cyclic adenosine 3′,5′-monophosphate dependent protein kinase and calmodulin). Troponin I reversibly inhibits Ca2+-activated tension. These results are consistent with thin filament regulation being responsible for Ca2+-activated tension in skinned fibers.

Original languageEnglish (US)
Pages (from-to)121-124
Number of pages4
JournalPflügers Archiv European Journal of Physiology
Issue number2
StatePublished - Dec 1 1981
Externally publishedYes


  • Ca
  • ITP
  • Limulus
  • Myosin light chain
  • Phosphorylation
  • Skinned fibers

ASJC Scopus subject areas

  • Physiology


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