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Okadaic acid uncouples myosin light chain phosphorylation and tension in smooth muscle
Author(s) -
Tansey M.G.,
Hori M.,
Karaki H.,
Kamm K.E.,
Stull J.T.
Publication year - 1990
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 - 10.1016/0014-5793(90)81272-p
Subject(s) - okadaic acid , myosin light chain kinase , myosin , phosphorylation , chemistry , immunoglobulin light chain , microbiology and biotechnology , biophysics , biochemistry , phosphatase , medicine , biology , antibody , immunology
Tracheal smooth muscle precontracted with carbachol relaxes upon the addition of 3 μM okadaic add. Although cytosolic Ca 2+ concentrations decrease, myosin light chain remains highly phosphorylated (50%). In smooth muscle treated with carbachol alone or carbachol plus okadaic acid 32 P is incorporated into a single peptide on myosin light chain which corresponds to the site phosphorylated by myosin light chain kinase. Treatment with okadaic acid alone does not result in myosin light chain phosphorylation or tension development. These results suggest that a cellular mechanism other than myosin light chain phosphorylation can regulate contractile tension.