Effects of protein kinase a on the phosphorylation status and transverse stiffness of cardiac myofibrils

J Pharmacol Sci. 2013;123(3):279-83. doi: 10.1254/jphs.13110sc. Epub 2013 Oct 22.

Abstract

Stimulation of β-adrenergic receptors in cardiac myocytes activates cyclic AMP-dependent protein kinase A (PKA). PKA-mediated phosphorylation of myofibrils decreases their longitudinal stiffness, but its effect on transverse stiffness is not fully understood. We thus examined the effects of PKA treatment on the transverse stiffness of cardiac myofibrils by atomic force microscopy and determined the phosphorylation levels of myofibril components by SDS-PAGE. Transverse stiffness was significantly decreased by PKA treatment concomitantly with increased phosphorylation of troponin I, myosin-binding protein C, and titin (also called connectin). Subsequent treatment with protein phosphatase 1 abrogated these PKA-mediated effects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carrier Proteins / metabolism
  • Cells, Cultured
  • Connectin / metabolism
  • Cyclic AMP-Dependent Protein Kinases / antagonists & inhibitors
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Cyclic AMP-Dependent Protein Kinases / pharmacology*
  • Cyclic AMP-Dependent Protein Kinases / physiology
  • Elasticity / drug effects*
  • Electrophoresis, Polyacrylamide Gel
  • Humans
  • Microscopy, Atomic Force
  • Myocytes, Cardiac / metabolism*
  • Myocytes, Cardiac / physiology*
  • Myocytes, Cardiac / ultrastructure
  • Myofibrils / metabolism
  • Myofibrils / physiology*
  • Myofibrils / ultrastructure
  • Phosphorylation
  • Protein Phosphatase 1 / pharmacology
  • Receptors, Adrenergic, beta
  • Troponin I / metabolism

Substances

  • Carrier Proteins
  • Connectin
  • Receptors, Adrenergic, beta
  • Troponin I
  • myosin-binding protein C
  • Cyclic AMP-Dependent Protein Kinases
  • Protein Phosphatase 1