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The dynamic role of cardiac myosin binding protein-C during ischemia

Robert S Decker1, Sakie Nakamura, Marlene L Decker

  • 1Feinberg Cardiovascular Research Institute, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.

Journal of Molecular and Cellular Cardiology
|January 28, 2012
PubMed

Insights

Cardiac myosin binding protein C (cMyBP-C) dephosphorylation during ischemia/reperfusion leads to thick filament degradation and contractile dysfunction. This highlights cMyBP-C

Area of Science:

  • Cardiovascular Biology
  • Muscle Physiology
  • Cardiac Myofibril Structure

Background:

  • Cardiac myosin binding protein C (cMyBP-C) is crucial for myocardial contractility and myofibril stability.
  • Mutations in cMyBP-C are linked to cardiomyopathy and heart failure.
  • cMyBP-C has distinct functional domains, with phosphorylation sites modulating contractility and C-terminal interactions stabilizing thick filaments.

Purpose of the Study:

  • To investigate the role of cMyBP-C in structural and functional changes following myocardial ischemia/reperfusion.
  • To elucidate the sequential changes in cMyBP-C, cardiac contractility, and thick filament structure during ischemia/reperfusion.

Main Methods:

  • Utilized chronically instrumented dogs with biopsied myocardial specimens.
  • Employed 1D and 2D electrophoresis, electron microscopy, and immunocytochemistry with domain-specific antibodies.
  • Analyzed sequential changes in cMyBP-C structure and phosphorylation status (specifically serine 282).

Main Results:

  • Ischemia induced dephosphorylation of cMyBP-C.
  • Reperfusion led to the release of dephosphorylated cMyBP-C from myofibrils and activated its proteolysis.
  • This resulted in increased thick filament degradation and persistent contractile dysfunction, closely linked to serine 282 dephosphorylation.

Conclusions:

  • Dephosphorylation of cMyBP-C during ischemia/reperfusion compromises its stabilizing function.
  • Loss of cMyBP-C's structural integrity leads to premature thick filament degradation and impaired cardiac contractility.
  • These findings underscore the critical role of cMyBP-C phosphorylation in maintaining cardiac function under stress.

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