title: Human colony stimulating factor-1 receptor activates the C-raf-1 proto-oncogene kinase.
abstract: The proto-oncogene c-raf-1 encodes a 74 kD serine/threonine kinase. Recently, it has been shown that Raf kinase activity is stimulated by platelet derived growth factor (PDGF) treatment of receptor bearing cells, and that p74 is a direct substrate for PDGF receptor. CSF-1 treatment of BeWo cells, a human choriocarcinoma cell line, and mouse NIH 3T3 cells expressing a transfected human CSF-1 receptor cDNA, was associated with a 3-4 fold increase in phosphorylation of a 74 kD protein immunoprecipitated with affinity purified Raf-1 antibody. The kinase activity of p74 was increased 2-3 fold against two exogenous substrates following CSF-1 treatment of the transfected cells. These observations suggest that Raf-1 protein is a downstream second messenger molecule in CSF-1 mediated signal transduction.
authors.affiliation: Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio 78284-7762.
authors.forename: G G
authors.initials: GG
authors.lastname: Choudhury
authors.forename: V L
authors.initials: VL
authors.lastname: Sylvia
authors.forename: A
authors.initials: A
authors.lastname: Pfeifer
authors.forename: L M
authors.initials: LM
authors.lastname: Wang
authors.forename: E A
authors.initials: EA
authors.lastname: Smith
authors.forename: A Y
authors.initials: AY
authors.lastname: Sakaguchi
mesh_terms: D000818:Animals; D002460:Cell Line; D005786:Gene Expression Regulation; D006801:Humans; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D051379:Mice; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D019908:Proto-Oncogene Proteins c-raf; D011519:Proto-Oncogenes; D016184:Receptors, Colony-Stimulating Factor / Q000235:genetics / Q000502:physiology*; D014162:Transfection
chemical_list: C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D016184:Receptors, Colony-Stimulating Factor; D016173:Macrophage Colony-Stimulating Factor; D011505:Protein-Tyrosine Kinases; D019908:Proto-Oncogene Proteins c-raf