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Dephosphorylation of distinct sites on the 20 kDa myosin light chain by smooth muscle myosin phosphatase
Author(s) -
Feng Jianhua,
Ito Masaaki,
Nishikawa Masakatsu,
Okinaka Tsutomu,
Isaka Naoki,
Hartshorne David J,
Nakano Takeshi
Publication year - 1999
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(99)00337-3
Subject(s) - dephosphorylation , myosin , myosin light chain kinase , phosphatase , myosin light chain phosphatase , protein subunit , phosphorylation , biochemistry , chemistry , immunoglobulin light chain , biology , microbiology and biotechnology , gene , antibody , immunology
The dephosphorylation of the myosin light chain kinase and protein kinase C sites on the 20 kDa myosin light chain by myosin phosphatase was investigated. The myosin phosphatase holoenzyme and catalytic subunit, dephosphorylated Ser‐19, Thr‐18 and Thr‐9, but not Ser‐1/Ser‐2. The role of non‐catalytic subunits in myosin phosphatase was to activate the phosphatase activity. For Ser‐19 and Thr‐18, this was due to a decrease in K m and an increase in k cat and for Thr‐9 to a decrease in K m . Thus, the distinction between the various sites is a property of the catalytic subunit.