Molecular and Cellular Biochemistry

, Volume 263, Issue 1, pp 73–80

Reduced cross-bridge dependent stiffness of skinned myocardium from mice lacking cardiac myosin binding protein-C

  • Bradley M. Palmer
  • Bradley K. McConnell
  • Guo Hua Li
  • Christine E. Seidman
  • J.G. Seidman
  • Thomas C. Irving
  • Norman R. Alpert
  • David W. Maughan
Article

DOI: 10.1023/B:MCBI.0000041849.60591.45

Cite this article as:
Palmer, B.M., McConnell, B.K., Li, G.H. et al. Mol Cell Biochem (2004) 263: 73. doi:10.1023/B:MCBI.0000041849.60591.45

Abstract

The role of cardiac myosin binding protein-C (MyBP-C) on myocardial stiffness was examined in skinned papillary muscles of wild-type (WT+/+) and homozygous truncated cardiac MyBP-C (MyBP-Ct/t) male mice. No MyBP-C was detected by gel electrophoresis or by Western blots in the MyBP-Ct/t myocardium. Rigor-bridge dependent myofilament stiffness, i.e., rigor minus relaxed stiffness, in the MyBP-Ct/t myocardium (281 ± 44 kN/m2) was 44% that in WT+/+ (633 ± 141 kN/m2). The center-to-center spacing between thick filaments as determined by X-ray diffraction in MyBP-Ct/t (45.0 ± 1.2 nm) was not significantly different from that in WT+/+ (43.2 ± 0.9 nm). The fraction of cross-sectional area comprised of myofibrils, as determined by electron microscopy, was reduced in the MyBP-Ct/t (39.9%) by 10% compared to WT+/+ (44.5%). These data suggest that the 56% reduction in rigor-bridge dependent stiffness of the skinned MyBP-Ct/t myocardium could not be due solely to a 10% reduction in the number of thick filaments per cross-sectional area and must also be due to approximately 50% reduction in the stiffness of the rigor-bridge attached thick filaments lacking MyBP-C. (Mol Cell Biochem 263: 73–80, 2004)

C-proteinisometric tensioncompliancehomozygoustruncated protein

Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • Bradley M. Palmer
    • 1
  • Bradley K. McConnell
    • 2
  • Guo Hua Li
    • 2
  • Christine E. Seidman
    • 1
  • J.G. Seidman
    • 1
  • Thomas C. Irving
    • 3
  • Norman R. Alpert
    • 1
  • David W. Maughan
    • 1
  1. 1.Department of Molecular Physiology and BiophysicsUniversity of VermontBurlingtonUSA
  2. 2.Department of GeneticsHoward Hughes Medical Institute and Harvard Medical SchoolBostonUSA
  3. 3.Center for Synchrotron Radiation Research and Instrumentation and Department of Biological, Chemical, and Physical SciencesIllinois Institute of TechnologyChicagoUSA