Regulation of myosin light chain kinase by reversible phosphorylation and calcium-calmodulin.
1) Myosin light chain kinases from smooth muscle and platelets can be phosphorylated by the catalytic subunit of cAMP-dependent protein kinase. 2) Phosphorylation of both kinases, in the absence of calmodulin, markedly decreases kinase activity. 3) The decrease in smooth muscle myosin kinase activity is due to a decreased affinity of the phosphorylated kinase for calmodulin. 4) Dephosphorylation of the smooth muscle kinase by a phosphatase isolated from smooth muscle restores the affinity of the kinase for calmodulin.
D000818:Animals; D001792:Blood Platelets / Q000201:enzymology; D002118:Calcium / Q000494:pharmacology*; D002135:Calcium-Binding Proteins / Q000494:pharmacology*; D002147:Calmodulin / Q000494:pharmacology*; D005895:Gizzard, Avian / Q000201:enzymology; D006801:Humans; D007700:Kinetics; D009219:Myosin-Light-Chain Kinase; D043263:Myosin-Light-Chain Phosphatase; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D014422:Turkeys
D002135:Calcium-Binding Proteins; D002147:Calmodulin; D011494:Protein Kinases; D009219:Myosin-Light-Chain Kinase; D010749:Phosphoprotein Phosphatases; D043263:Myosin-Light-Chain Phosphatase; D002118:Calcium