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Activation of protein kinase C by the 14‐3‐3 proteins homologous with Exol protein that stimulates calcium‐dependent exocytosis
Author(s) -
Isobe Toshiaki,
Hiyane Yuriko,
Ichimura Tohru,
Okuyama Tsuneo,
Takahashi Nobuhiro,
Nakajo Shigeo,
Nakaya Kazuyasu
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)81257-m
Subject(s) - protein kinase a , mitogen activated protein kinase kinase , protein kinase c , map2k7 , exocytosis , ask1 , microbiology and biotechnology , biology , c raf , cgmp dependent protein kinase , biochemistry , cyclin dependent kinase 2 , cyclin dependent kinase 9 , map kinase kinase kinase , kinase , chemistry , secretion
The 14‐3‐3 proteins are a family of acidic proteins found mainly in the brain and are suggested to have a role in monoamine synthesis based on their ability to activate tyrosine and tryptophan hydroxylases in the presence of type II Ca 2+ /calmodulin‐dependent protein kinase. Recently, however, it has been demonstrated that a member of the 14‐3‐3 family, termed Exol, stimulates Ca 2+ ‐dependent exocytosis in permeabilized adrenal chromaffin cells, suggesting that this protein family may influence the protein kinase C‐mediated control of Ca 2+ ‐dependent exocytosis. Here we show that the 14‐3‐3 proteins activate protein kinase C at about 2‐fold more than the known level of the activated protein kinase, i.e. the activity of protein kinase C in the presence of Ca 2+ and phospholipids. This raises the possibility that the cellular activity of protein kinase C is regulated by diverse members of the 14‐3‐3 family and that the reported ability of Exol to reactivate Ca 2+ ‐dependent exocytosis is based on its stimulatory effect on protein kinase C activity. The 14‐3‐3 family, therefore, appears to be a multifunctional regulator of cell signalling processes mediated by two types of Ca 2+ ‐dependent protein kinase, protein kinase C and type II calmodulin‐dependent protein kinase.