title: Identification of EGF receptor C-terminal sequences 1005-1017 and di-leucine motif 1010LL1011 as essential in EGF receptor endocytosis.
abstract: Most studies regarding the role of epidermal growth factor (EGF) receptor (EGFR) C-terminal domain in EGFR internalization are done in the context of EGFR kinase activation. We recently showed that EGF-induced EGFR internalization is directly controlled by receptor dimerization, rather than kinase activation. Here we studied the role of EGFR C-terminus in EGF-induced EGFR internalization with or without EGFR kinase activation. We showed that graduate truncation of EGFR from C-terminus to 1044 did not affect EGF-induced EGFR endocytosis with or without kinase activation. However, truncation to 991 or further completely inhibited EGFR endocytosis. Graduate truncation within 991-1044 progressively lower EGF-induced EGFR endocytosis with most significant effects observed for residues 1005-1017. The endocytosis patterns of mutant EGFRs are independent of EGFR kinase activation. The residues 1005-1017 were also required for EGFR internalization triggered by non-ligand-induced receptor dimerization. This indicates that residues 1005-1017 function as an internalization motif, rather than a dimerization motif, to mediate EGFR internalization. Furthermore, we showed that the di-leucine motif 1010LL1011 within this region is essential in mediating EGF-induced rapid EGFR internalization independent of kinase activation. We conclude that EGFR C-terminal sequences 1005-1017 and the 1010LL1011 motif are essential for EGF-induced EGFR endoytosis independent of EGFR kinase activation and autophosphorylation.
authors.affiliation: Department of Cell Biology and Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.forename: Fuxiang
authors.initials: F
authors.lastname: Zhu
authors.forename: Zhixiang
authors.initials: Z
authors.lastname: Wang
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D019281:Dimerization; D004705:Endocytosis / Q000502:physiology*; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology / Q000502:physiology; D066246:ErbB Receptors / Q000378:metabolism*; D006801:Humans; D007930:Leucine / Q000378:metabolism*; D051379:Mice; D009154:Mutation; D010766:Phosphorylation; D017434:Protein Structure, Tertiary
chemical_list: D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D007930:Leucine