title: Essential role of c-Cbl in amphiregulin-induced recycling and signaling of the endogenous epidermal growth factor receptor.
abstract: The intracellular processing of the epidermal growth factor receptor (EGFR) induced by epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) has been studied meticulously, with the former resulting in EGFR degradation and the latter in EGFR recycling to the plasma membrane. However, little is known about how other EGF family growth factors affect the trafficking of the EGFR. Additionally, although both EGF and TGF-alpha have been shown to effectively induce initial c-Cbl (ubiquitin ligase)-mediated ubiquitination of the EGFR, limited information is available regarding the role of c-Cblin the trafficking and signaling of recycling EGFR. Thus, in this study, we investigated the roles of c-Cblin endogenous EGFR trafficking and signaling after stimulation with amphiregulin (AR). We demonstrated that a physiological concentration of AR induced recycling of the endogenous EGFR to the plasma membrane, which correlated closely with transient association of the EGFR with c-Cbl and transient EGFR ubiquitination. Most importantly, we used c-Cbl small interfering RNA (siRNA) duplexes and ac-Cbl dominant negative mutant to show that c-Cbl is critical for the efficient transition of the EGFR from early endosomes to a recycling pathway and that c-Cbl regulates the duration of extracellular signal regulated kinase 1/2 mitogen-activated protein kinase (ERK1/2 MAPK) phosphorylation. These data support novel functions of c-Cbl in mediating recycling of EGF receptors to the plasma membrane, as well as in mediating the duration of activation (transient vs sustained) of ERK1/2 MAPK phosphorylation.
authors.affiliation: Nephrology Division, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
authors.forename: Aleksander
authors.initials: A
authors.lastname: Baldys
authors.forename: Monika
authors.initials: M
authors.lastname: Göoz
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Morinelli
authors.forename: Mi-Hye
authors.initials: MH
authors.lastname: Lee
authors.forename: John R
authors.initials: JR
authors.lastname: Raymond
authors.forename: Louis M
authors.initials: LM
authors.lastname: Luttrell
authors.forename: John R
authors.initials: JR
authors.lastname: Raymond
mesh_terms: D066258:Amphiregulin; D015153:Blotting, Western; D002460:Cell Line; D066255:EGF Family of Proteins; D004705:Endocytosis; D066246:ErbB Receptors / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006023:Glycoproteins / Q000494:pharmacology*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology*; D008024:Ligands; D018613:Microscopy, Confocal; D010766:Phosphorylation; D050721:Proto-Oncogene Proteins c-cbl / Q000502:physiology*; D034622:RNA Interference; D034741:RNA, Small Interfering; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D054875:Ubiquitination
chemical_list: C587848:AREG protein, human; D066258:Amphiregulin; D066255:EGF Family of Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D034741:RNA, Small Interfering; D050721:Proto-Oncogene Proteins c-cbl; D066246:ErbB Receptors