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Intracellular signal transduction for serum activation of the hyaluronan synthase in eukaryotic cell lines
Author(s) -
Klewes Ludger,
Prehm Peter
Publication year - 1994
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041600317
Subject(s) - cycloheximide , forskolin , phosphorylation , protein kinase c , phorbol , kinase , microbiology and biotechnology , intracellular , atp synthase , protein kinase a , phosphatase , biochemistry , hyaluronan synthase , signal transduction , cholera toxin , chemistry , biology , enzyme , receptor , protein biosynthesis , endocrinology
Abstract Hyaluronan synthase was activated in B6 cells or 3T3 fibroblasts by foetal calf serum with maximal activity after 6 h. Activation was inhibited by cycloheximide or by the protein kinase inhibitors H‐7 or H‐8, indicating that transcription as well as phosphorylation was required for activation. The activation by serum was markedly prolonged, when serum was added together with cholera toxin or theophylline. Without serum stimulation the hyaluronan synthase could also be activated by phorbol‐12‐myristate‐13‐acetate, by dibutyryl‐c‐AMP, or by forskolin. Increasing the intracellular Ca‐ion concentration with a Ca‐ionophore also led to an activation. The activation of the drugs was not synergistic. In isolated plasma membranes the synthase activity could be decreased by phosphatase treatment and enhanced by ATP in B6 cells and by ATP in the presence of phorbol‐12‐myristate‐13‐acetate in 3T3 fibroblasts. Stimulation correlated with increased transcription and phosphorylation of the 52 kD hyaluronan synthase at serine residues. The results led to the conclusion that hyaluronan synthase is induced by transcription and activated by phosphorylation by protein kinase C, c‐AMP‐dependent protein kinases, or Ca‐ion‐dependent protein kinases. © 1994 Wiley‐Liss, Inc.