tailieunhanh - Báo cáo Y học: Chimeric receptor analyses of the interactions of the ectodomains of ErbB-1 with epidermal growth factor and of those of ErbB-4 with neuregulin

A series of chimeric receptors was generated between the epidermal growth factor (EGF) receptor, ErbB-1, and its homologue, ErbB-4, to investigate the roles of the extracellular domains (I–IV) in the ligand specificities. As compared with ErbB-1 and the chimeras with both domains I and III of ErbB-1, the chimeras with only one of these domains exhibited reduced binding of 125I-labeled EGF. Particularly, the contribution of domain III was appreciably larger than that of domain I of ErbB-1 in 125I-labeled EGF binding. Nevertheless, the chimeras with domain III of ErbB-1 and domain I of ErbB-4 were prevented from binding to 125. | Eur. J. Biochem. 269 2323-2329 2002 FEBS 2002 doi Chimeric receptor analyses of the interactions of the ectodomains of ErbB-1 with epidermal growth factor and of those of ErbB-4 with neuregulin Jae-Hoon Kim1 Kazuki Saito1 2 and Shigeyuki Yokoyama1 2 3 1Yokoyama CytoLogic Project ERATO Japan Science and Technology Corporation c o Tsukuba Research Consortium Tokodai Tsukuba Japan 2RIKEN Genomic Sciences Center Suehiro-cho Tsurumi Yokohama Japan 3Department of Biophysics and Biochemistry Graduate School of Science University of Tokyo Hongo Bunkyo-ku Tokyo Japan A series of chimeric receptors was generated between the epidermal growth factor EGF receptor ErbB-1 and its homologue ErbB-4 to investigate the roles of the extracellular domains I-IV in the ligand specificities. As compared with ErbB-1 and the chimeras with both domains I and III of ErbB-1 the chimeras with only one of these domains exhibited reduced binding of 125I-labeled EGF. Particularly the contribution of domain III was appreciably larger than that of domain I of ErbB-1 in 125I-labeled EGF binding. Nevertheless the chimeras with domain III of ErbB-1 and domain I of ErbB-4 were prevnnred omm hini limi to 125I-labeled EGF competitively by the ErbB-4 ligand neu-regulin NRG . On the other hand NRG did not compete with 125I-labeled EGF for binding to the chimeras with the ErbB-1 domain I and the ErbB-4 domain In. Therftore NRG binding to ErbB-4 e ịot m much more on nOm im I than on domain III. With respect to autophosphorylation and subsequent ERK activation EGF activated the chimeras with either domain I or III of ErbB-1. In contrast NRG activated the chimeras with the ErbB-4 domaín I and the ErbB-1 domain III but not those with the ErbB-1 domain I and the ErbB-4 domaín 111. There lore. the relative contributions between domains I and III of ErbB-4 in the NRG signaling are different from those of ErbB-1 in the EGF signaling. Keywords chimeric receptors epidermal growth .