The influence of P-light chain phosphorylation by myosin light chain kinase on the calcium sensitivity of chemically skinned heart fibres.
Phosphorylation of the P-light chain of myosin might be involved in the regulation of cardiac contractility. Thus an enhanced phosphorylation level of the P-light chain catalyzed by Ca2+-calmodulin-dependent myosin light chain kinase (MLCK) increased significantly the Ca2+ sensitivity of chemically skinned ventricular fibre bundles of the pig. This effect was reversible. Whereas force development at submaximal Ca2+ concentration (pCa 5.5) increased by approximately 50% in the presence of MLCK, maximum tension achieved at maximum Ca2+-concentration (pCa 4.3) was not affected.
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D006321:Heart / Q000187:drug effects*; D009200:Myocardial Contraction / Q000187:drug effects; D009219:Myosin-Light-Chain Kinase; D009218:Myosins / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D013552:Swine
D011494:Protein Kinases; D009219:Myosin-Light-Chain Kinase; D009218:Myosins; D002118:Calcium