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Phosphorylation of CPI‐17, an inhibitory phosphoprotein of smooth muscle myosin phosphatase, by Rho‐kinase
Author(s) -
Koyama Mutsumi,
Ito Masaaki,
Feng Jianhua,
Seko Tetsuya,
Shiraki Katsuya,
Takase Koujiro,
Hartshorne David J.,
Nakano Takeshi
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01654-9
Subject(s) - phosphorylation , rho associated protein kinase , myosin light chain kinase , phosphatase , kinase , chemistry , myosin , mitogen activated protein kinase kinase , microbiology and biotechnology , protein kinase a , biochemistry , biology
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.