An insertional mutant of epidermal growth factor receptor allows dissection of diverse receptor functions.

摘要: Cultured NIH-3T3 cells devoid of endogenous EGF-receptors were transfected with cDNA constructs encoding normal human EGF-receptor and a construct an insertional mutant the containing four additional amino acids in kinase domain after residue 708. Unlike wild-type receptor expressed these which exhibits EGF-stimulatable protein tyrosine activity, lacks activity both vitro vivo. Despite this deficiency is properly processed, it binds EGF high low affinity binding sites. Moreover, undergoes efficient EGF-mediated endocytosis. However, fails to stimulate DNA synthesis unable phosphorylation S6 ribosomal expressing mutant. Hence, proposed that essential for initiation induced by EGF. processing, expression surface receptors internalization, require neither nor autophosphorylation. Interestingly, phorbol ester (TPA) abolish state also This result consistent notion kinase-C loss caused TPA.