Transformation-specific interaction of the bovine papillomavirus E5 oncoprotein with the platelet-derived growth factor receptor transmembrane domain and the epidermal growth factor receptor cytoplasmic domain.

摘要: Abstract The bovine papillomavirus E5 transforming protein appears to activate both the epidermal growth factor receptor (EGF-R) and platelet-derived (PDGF-R) by a ligand-independent mechanism. To further investigate ability of receptors different classes determine whether this stimulation occurs through extracellular domain required for ligand activation, we constructed chimeric genes encoding PDGF-R EGF-R interchanging extracellular, membrane, cytoplasmic coding domains. Chimeras were transfected into NIH 3T3 CHO(LR73) cells. All chimeras expressed stable which, upon addition appropriate ligand, could be activated as assayed tyrosine autophosphorylation biological transformation. Cotransfection with wild-type resulted in activation receptors, provided that contained either transmembrane or EGF-R. Chimeric these domains exhibited highest level E5-induced biochemical stimulation. These results imply activates EGR-R two distinct mechanisms, neither which specifically involves receptor. Consistent data, coimmunoprecipitation studies demonstrated formed complex any chimera an domain, those containing demonstrating greatest efficiency formation. suggest although are directly formation E5-containing complex.