Protein kinase C-dependent activation of a myelin basic protein kinase by gastrin-releasing peptide in Swiss 3T3 fibroblasts.
Addition of gastrin releasing peptide to serum-starved Swiss 3T3 mouse fibroblasts results in a transient appearance of a myelin basic protein-kinase activity in cytosolic extracts. Increased kinase activity is also observed upon stimulation of cells with bradykinin, epidermal growth factor or 4 beta-phorbol dibutyrate. Chromatographic analysis of the cytosolic extracts show that both gastrin-releasing peptide and 4 beta-phorbol dibutyrate induce the appearance of a kinase activity similar to that induced by epidermal growth factor. The response to gastrin-releasing peptide is abolished by down-regulation of protein kinase C and attenuated by acute inhibition of protein kinase C using staurosporine. The effect of epidermal growth factor was also suppressed under these conditions, albeit to a lesser extent. The results indicate (1) that activation of myelin basic protein kinase(s) may be common to different growth factors, and (2) that protein kinase C may participate in this response, at least in the case of gastrin-releasing peptide.
Department of Physiological Chemistry, Karolinska Institutet, Stockholm, Sweden.
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Hansson
D016475:3T3 Cells; D000818:Animals; D015536:Down-Regulation; D004789:Enzyme Activation; D019886:Gastrin-Releasing Peptide; D005755:Gastrins / Q000502:physiology*; D038362:Glycogen Synthase Kinase 3; D006133:Growth Substances / Q000502:physiology; D007700:Kinetics; D051379:Mice; D010455:Peptides / Q000502:physiology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*
D005755:Gastrins; D006133:Growth Substances; D010455:Peptides; D019886:Gastrin-Releasing Peptide; D011494:Protein Kinases; D011493:Protein Kinase C; D038362:Glycogen Synthase Kinase 3