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PKC α regulates thrombin‐induced PDGF‐B chain gene expression in mesangial cells
Author(s) -
Biswas Purba,
Abboud Hanna E.,
Kiyomoto Hideyasu,
Wenzel Ulrich O.,
Grandaliano Giuseppe,
Choudhury Goutam Ghosh
Publication year - 1995
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(95)01025-a
Subject(s) - protein kinase c , thrombin , pkc alpha , diacylglycerol kinase , microbiology and biotechnology , mesangial cell , phospholipase c , phorbol , chemistry , biology , signal transduction , biochemistry , in vitro , platelet , immunology
Thrombin is a potent mitogen for mesangial cells and stimulates PDGF B‐chain gene expression in these cells. It also activates phospholipase C (PLC) resulting in an increase in cytosolic Ca 2+ and diacylglycerol (DAG) that are the physiological activators of protein kinase C (PKC). Immunoprecipitation of specific PKC isotypes from thrombin‐stimulated mesangial cells with subsequent measurement of their enzymatic activity shows activation of Ca 2+ ‐dependent PKC α and Ca 2+ ‐independent PKC Σ in a time dependent manner. Optimum activation of both of these isozymes was obtained at 60 minutes. PKC α activity increased 83% over basal while activity of PKC Σ increased 104%. Prolonged exposure of mesangial cells to phorbol myristate acetic acid (PMA) inhibited the enzymatic activity of PKC α but not PKC Σ. This inhibition of PKC α had no effect on thrombin‐induced DNA synthesis but abolished PDGF B‐chain gene expression induced by thrombin. These data provide the first evidence that PKC α activation is necessary for thrombin‐induced PDGF B‐chain gene expression but not for thrombin‐induced DNA synthesis.