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Phosphorylation of a 16‐kDa protein by diacylglycerol‐activated protein kinase C in vitro and by vasopressin in intact hepatocytes
Author(s) -
Cooper Ronald H.,
Kobayashi Koichi,
Williamson John R.
Publication year - 1984
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(84)80057-5
Subject(s) - diacylglycerol kinase , phosphorylation , protein kinase c , protein phosphorylation , protein kinase a , cytosol , vasopressin , hepatocyte , biology , biochemistry , kinase , in vitro , microbiology and biotechnology , endocrinology , enzyme
A 16‐kDa protein present in a purified rat liver plasma membrane fraction and also in cytosol can be phosphorylated by endogenous diacylglycerol‐activated protein kinase C. In intact hepatocytes prelabeled with 32 P, vasopressin causes a rapid increase in the phosphorylation of a 16‐kDa protein having a similar p I value to that observed in in vitro studies. These findings suggest that vasopressin‐induced phosphorylation of the 16‐kDa in the intact hepatocyte may reflect increased activity of protein kinase C, secondary to membrane polyphosphoinositide breakdown. Phosphorylation of the 16‐kDa protein may thus be part of the coordinated mechanism associated with hormonal regulation of cellular Ca 2+ fluxes.