Abstract
Phosphorylation of CPI-17 by Rho-associated kinase (Rho-kinase) and its effect on myosin phosphatase (MP) activity were investigated. CPI-17 was phosphorylated by Rho-kinase to 0.92 mol of P/mol of CPI-17 in vitro. The inhibitory phosphorylation site was Thr(38) (as reported previously) and was identified using a point mutant of CPI-17 and a phosphorylation state-specific antibody. Phosphorylation by Rho-kinase dramatically increased the inhibitory effect of CPI-17 on MP activity. Thus, CPI-17 as a substrate of Rho-kinase could be involved in the Ca(2+) sensitization of smooth muscle contraction as a downstream effector of Rho-kinase.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Intracellular Signaling Peptides and Proteins
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Muscle Proteins / genetics
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Muscle Proteins / metabolism*
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Muscle, Smooth / metabolism*
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Myosin-Light-Chain Phosphatase
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Phosphoprotein Phosphatases / antagonists & inhibitors*
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Phosphoproteins / genetics
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Phosphoproteins / metabolism*
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Phosphorylation
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Point Mutation
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Protein Serine-Threonine Kinases / metabolism*
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rho-Associated Kinases
Substances
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Intracellular Signaling Peptides and Proteins
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Muscle Proteins
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Phosphoproteins
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Protein Serine-Threonine Kinases
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rho-Associated Kinases
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Phosphoprotein Phosphatases
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Myosin-Light-Chain Phosphatase