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Phosphorylation of vascular smooth muscle caldesmon by endogenous kinase
Author(s) -
Pinter Katalin,
Marston Steven B.
Publication year - 1992
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(92)80665-4
Subject(s) - caldesmon , phosphorylation , actin , myosin , biochemistry , endogeny , vascular smooth muscle , microbiology and biotechnology , kinase , chemistry , myosin light chain kinase , calmodulin , biology , smooth muscle , enzyme , endocrinology
Caldesmon was phosphorylated up to 1.2 molP i /mol using a partially purified endogenous kinase fraction. The phosphorylation site was within the C‐terminal 99 amino acids. We were also able to phosphorylate caldesmon incorporated into native and synthetic smooth muscle thin filaments. Phosphorylation did not alter caldesmon binding to actin or inhibition or actomyosin ATPase. It also did not change Ca 2+ sensitivity in native thin filaments. Phosphorylated caldesmon bound to myosin less than unphosphorylated caldesmon, especially when the myosin was also not phosphorylated. This work did not support the hypothesis that caldesmon function is modulated by phosphorylation.