title: Phosphorylation of CPI-17, an inhibitory phosphoprotein of smooth muscle myosin phosphatase, by Rho-kinase.
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.
authors.affiliation: First Department of Internal Medicine, Mie University School of Medicine, Tsu, Mie 514-8507, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Koyama
authors.forename: M
authors.initials: M
authors.lastname: Ito
authors.forename: J
authors.initials: J
authors.lastname: Feng
authors.forename: T
authors.initials: T
authors.lastname: Seko
authors.forename: K
authors.initials: K
authors.lastname: Shiraki
authors.forename: K
authors.initials: K
authors.lastname: Takase
authors.forename: D J
authors.initials: DJ
authors.lastname: Hartshorne
authors.forename: T
authors.initials: T
authors.lastname: Nakano
mesh_terms: D000818:Animals; D047908:Intracellular Signaling Peptides and Proteins; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D009130:Muscle, Smooth / Q000378:metabolism*; D043263:Myosin-Light-Chain Phosphatase; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D017354:Point Mutation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D054460:rho-Associated Kinases
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D009124:Muscle Proteins; D010750:Phosphoproteins; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D010749:Phosphoprotein Phosphatases; D043263:Myosin-Light-Chain Phosphatase