Myosin-binding protein C phosphorylation, myofibril structure, and contractile function during low-flow ischemia

Robert S. Decker*, Marlene L. Decker, Irina Kulikovskaya, Sakie Nakamura, Daniel C. Lee, Kathleen Harris, Francis J. Klocke, Saul Winegrad

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

72 Scopus citations

Abstract

Background - Contractile dysfunction develops in the chronically instrumented canine myocardium after bouts of low-flow ischemia and persists after reperfusion. The objective of this study is to identify whether changes in the phosphorylation state of myosin-binding protein C (MyBP-C) are a potential cause of dysfunction. Methods and Results - During low-flow ischemia, MyBP-C is dephosphorylated, and the number of actomyosin cross-bridges in the central core of the sarcomere decreases as thick filaments dissemble from the periphery of the myofibril. During reperfusion, MyBP-C remains dephosphorylated, and its degradation is accelerated. Conclusions - Dephosphorylation of MyBP-C may initiate changes in myofibril thick filament structure that decrease the interaction of myosin heads with actin thin filaments. Limiting the formation of actomyosin cross-bridges may contribute to the contractile dysfunction that is apparent after low-flow ischemia. Breakdown of MyBP-C during reperfusion may prolong myocardial stunning.

Original languageEnglish (US)
Pages (from-to)906-912
Number of pages7
JournalCirculation
Volume111
Issue number7
DOIs
StatePublished - Feb 22 2005

Keywords

  • Contractility
  • Ischemia
  • Myocytes
  • Myosins
  • Phosphorylation

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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