Epidermal Growth Factor Stimulates Phosphorylation of RAF-1 Independently of Receptor Autophosphorylation and Internalization
Document Type
Article
Publication Date
9-6-1991
Description
Phosphorylation of the RAF-1 protooncogene product and activation of its associated serine/threonine kinase are common features of the response of cells to peptide growth factors. We have used wild-type and mutant epidermal growth factor (EGF) receptors to investigate mechanisms of RAF-1 phosphorylation. In vivo EGF treatment rapidly stimulated phosphorylation of RAF-1 exclusively on serine residues. Stimulation of RAF-1 phosphorylation occurred at 37 °C but not at 4 °C and persisted after dissociation of EGF from its receptor. EGF-induced RAF-1 serine phosphorylation required the intrinsic tyrosine kinase activity of the EGF receptor but was independent of EGF receptor self-phosphorylation and of ligand-induced receptor internalization. Down-regulation of protein kinase C did not affect the EGF-induced increase in RAF-1 phosphorylation. These data suggest that the activated tyrosine kinase activity of the EGF receptor enhances serine phosphorylation of RAF-1 via an intermediary molecule(s).
Citation Information
Baccarini, M.; Gill, G. N.; and Stanley, E. R.. 1991. Epidermal Growth Factor Stimulates Phosphorylation of RAF-1 Independently of Receptor Autophosphorylation and Internalization. Journal of Biological Chemistry. Vol.266(17). 10941-10945. https://pubmed.ncbi.nlm.nih.gov/1645717/ PMID: 1645717 ISSN: 0021-9258