Differential processing and turnover of the oncogenically activated neu/erb B2 gene product and its normal cellular counterpart.

摘要: In nontransformed DHFR/G-8 cells (NIH 3T3 transfected with normal rat neu gene), the gene product was initially synthesized as a 170-kDa protein bearing endoglycosidase H-sensitive oligosaccharide chains and then processed to 175-kDa mature form H-resistant, F-sensitive chains. Most of this appeared on cell surface 2 h following synthesis showed half-life approximately 3 h. presence growth factor(s) partially purified from bovine kidney, shortened less than 30 min. B104-1-1 activated oncogenically by point mutation that changes valine residue glutamic acid in putative transmembrane region), also precursor However, diminished very fast only 185-kDa which exhibited The possessed an unidentified post-translational modification addition N-linked Both forms mutationally increased tyrosine-specific phosphorylation compared those their counterparts cells. shared several features have been reported previously for ligand-activated platelet-derived factor receptor v-sis- or c-sis-transformed These properties include: 1) accelerated turnover rates its counterparts, 2) insensitivity rapid lysosomotropic amines, 3) vivo both forms. findings suggest may transform mimicking ligand-induced activation.