Figure 10.

EGF receptor cytoplasmic residues 675–697 are required for E3-13.7–mediated down-regulation. (A) Cartoon showing the EGF receptor transmembrane (TM) domain and the locations of a region bearing homology to E3-13.7, the kinase catalytic core, and the calcium response and internalization (CaIn) domain in the cytoplasmic tail. Locations of cytoplasmic truncations encoded by cDNAs with premature stop codons are also indicated. (B) Homologous sequences located at the E3-13.7 C terminus and the EGF receptor juxtamembrane domain are shown in the single-letter code and highlighted in dark gray. Locations of additional consensus tyrosine-based sorting signals in E3-13.7 (72-YLRH and 76-HPQY) are highlighted in light gray. (C) NR6 cell lines expressing each of the EGF receptor proteins indicated in the figure were infected with adenoviruses with (+) or without (−) an intact E3-13.7 ORF. Cells were metabolically labeled for 1 h, incubated in chase medium for 6 h, and harvested for immunoprecipitation with a human EGF receptor antibody specific for an external epitope. Immunoprecipitates were resolved by SDS-PAGE for fluorography.