Phosphorylation of Thr695 and Thr850 on the myosin phosphatase target subunit: inhibitory effects and occurrence in A7r5 cells.
Major sites for Rho-kinase on the myosin phosphatase target subunit (MYPT1) are Thr695 and Thr850. Phosphorylation of Thr695 inhibits phosphatase activity but the role of phosphorylation at Thr850 is not clear and is evaluated here. Phosphorylation of both Thr695 and Thr850 by Rho-kinase inhibited activity of the type 1 phosphatase catalytic subunit. Rates of phosphorylation of the two sites were similar and efficacy of inhibition following phosphorylation was equivalent for each site. Phosphorylation of each site on MYPT1 was detected in A7r5 cells, but Thr850 was preferred by Rho-kinase and Thr695 was phosphorylated by an unidentified kinase(s).
Murányi
Andrea
A
Muscle Biology Group, Department of Nutritional Sciences, University of Arizona, 1177 E. 4th Street, Shantz 627, Tucson, AZ 85721-0038, USA.
Derkach
Dmitry
D
Erdodi
Ferenc
F
Kiss
Andrea
A
Ito
Masaaki
M
Hartshorne
David J
DJ
D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002645:Chickens; D007700:Kinetics; D009154:Mutation; D032389:Myocytes, Smooth Muscle; D043263:Myosin-Light-Chain Phosphatase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D021122:Protein Subunits / Q000378:metabolism; D051381:Rats; D013379:Substrate Specificity; D013912:Threonine / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000378:metabolism
D021122:Protein Subunits; D013912:Threonine; D043263:Myosin-Light-Chain Phosphatase; D020741:rho GTP-Binding Proteins