Phosphorylation of CPI‐17, an inhibitory phosphoprotein of smooth muscle myosin phosphatase, by Rho‐kinase

FEBS Letters

Feng, Jianhua²  Hartshorne, David J.¹  Ito, Masaaki²  Seko, Tetsuya²  Koyama, Mutsumi²  Shiraki, Katsuya²  Nakano, Takeshi²  Takase, Koujiro² 

[1] Muscle Biology Group, Shantz Building, University of Arizona, Tucson, AZ 85721, USA;First Department of Internal Medicine, Mie University School of Medicine, Tsu, Mie 514-8507, Japan

关键词: Rho-kinase;    Myosin phosphatase;    CPI-17;    Smooth muscle;    Ca2+ sensitization;    Rho-kinase;    Rho-associated kinase;    MP;    myosin phosphatase;    PP1;    type 1 protein phosphatase;    PP1cδ;    the δ isoform of the catalytic subunit of PP1;    MLCK;    myosin light chain kinase;    MLC20;    20 kDa myosin light chain;    PKC;    protein kinase C;    GST;    glutathione S-transferase;    GTPγS;    guanosine 5′-3-O-(thio)triphosphate;    SDS;    sodium dodecyl sulfate;    PAGE;    polyacrylamide gel electrophoresis;   

DOI  :  10.1016/S0014-5793(00)01654-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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 Thr³⁸ (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 Ca²⁺ sensitization of smooth muscle contraction as a downstream effector of Rho-kinase.

【 授权许可】

Unknown