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Evidence that (a) serine specific protein kinase(s) different from protein kinase C is responsible for the insulin‐stimulated actin phosphorylation by placental membrane
Author(s) -
Carrascosa J.M.,
Wieland O.H.
Publication year - 1986
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(86)80574-9
Subject(s) - protein kinase a , phosphorylation , serine , biochemistry , map2k7 , kinase , mitogen activated protein kinase kinase , c raf , cgmp dependent protein kinase , protein kinase c , chemistry , biology , cyclin dependent kinase 2
Partially purified phospholipid‐ and Ca 2+ ‐dependent protein kinase C from human placenta catalyzes the Mg‐ATP‐dependent phosphorylation of serine residues of purified rabbit muscle actin. Two tryptic [ 32 P]‐phosphopeptides were found on HPLC separation. Confirming the previous report by Machicao and Wieland [(1985) Curr. Top. Cell. Regul. 27, 95‐105], actin is phosphorylated at serine residues by human placental membranes, and this is stimulated by insulin. In the absence of insulin trypsin treatment yielded eight [ 32 P]phosphopeptides, two of which coincided with the ones due to protein kinase C. Insulin led to the appearance of three new [ 32 P]phosphopeptides. These results suggest that insulin stimulates (a) serine protein kinase(s) which, like protein kinase C, is present in placental membranes.