c-Cbl directs EGF receptors into an endocytic pathway that involves the ubiquitin-interacting motif of Eps15.
c-Cbl associates with the activated EGF receptor before endocytosis. We here reveal that the capacity of c-Cbl to promote receptor internalization depends on its ubiquitin ligase activity, which functionally connects the EGF receptor to Eps15, a mediator of clathrin-coated pit formation. EGF-induced phosphorylation of Eps15, as well as recruitment of Eps15 to the plasma membrane and its co-localization with the EGF receptor in endosomes required the ubiquitin ligase activity of c-Cbl. This suggested that ubiquitin provides a direct or indirect link between the receptor and Eps15. Indeed, EGF-induced redistribution of Eps15 to the plasma membrane and endosomes depended on its ubiquitin-interacting motif. Upon over-expression, the ubiquitin-interacting motif abrogated the capacity of c-Cbl to promote EGF receptor endocytosis and only allowed receptor internalization via a route that lacked Eps15. Our findings disclose a novel function for the c-Cbl ubiquitin ligase and identify ubiquitin as a module that directs the EGF receptor into an endocytic pathway involving Eps15.
de Melker
Annemieke A
AA
Division of Immunology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam.
van der Horst
Gerda
G
Borst
Jannie
J
D048868:Adaptor Proteins, Signal Transducing; D020816:Amino Acid Motifs; D000818:Animals; D016466:CHO Cells; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism*; D015151:Immunoblotting; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008856:Microscopy, Fluorescence; D010750:Phosphoproteins / Q000737:chemistry / Q000502:physiology*; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000378:metabolism / Q000502:physiology*; D050721:Proto-Oncogene Proteins c-cbl; D013997:Time Factors; D014443:Tyrosine / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism / Q000502:physiology*
D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; C082729:Eps15 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D025801:Ubiquitin; D014443:Tyrosine; D050721:Proto-Oncogene Proteins c-cbl; D044767:Ubiquitin-Protein Ligases; D066246:ErbB Receptors; C493849:Cbl protein, mouse