Abstract

Ligand-induced down-regulation controls the signaling potency of the epidermal growth factor receptor (EGFR/ErbB1). Overexpression studies have identified Cbl-mediated ubiquitinylation of EGFR as a mechanism of ligand-induced EGFR down-regulation. However, the role of endogenous Cbl in EGFR down-regulation and the precise step in the endocytic pathway regulated by Cbl remain unclear. Using Cbl-/- mouse embryonic fibroblast cell lines, we demonstrate that endogenous Cbl is essential for ligand-induced ubiquitinylation and efficient degradation of EGFR. Further analyses using Chinese hamster ovary cells with a temperature-sensitive defect in ubiquitinylation confirm a crucial role of the ubiquitin machinery in Cbl-mediated EGFR degradation. However, internalization into early endosomes did not require Cbl function or an intact ubiquitin pathway. Confocal immunolocalization studies indicated that Cbl-dependent ubiquitinylation plays a critical role at the early endosome to late endosome/lysosome sorting step of EGFR down-regulation. These findings establish Cbl as the major endogenous ubiquitin ligase responsible for EGFR degradation, and show that the critical role of Cbl-mediated ubiquitinylation is at the level of endosomal sorting, rather than at the level of internalization.

Original languageEnglish (US)
Pages (from-to)28950-28960
Number of pages11
JournalJournal of Biological Chemistry
Volume278
Issue number31
DOIs
StatePublished - Aug 1 2003

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Duan, L., Miura, Y., Dimri, M., Majumder, B., Dodge, I. L., Reddi, A. L., Ghosh, A., Fernandes, N., Zhou, P., Mullane-Robinson, K., Rao, N., Donoghue, S., Rogers, R. A., Bowtell, D., Naramura, M., Gu, H., Band, V., & Band, H. (2003). Cbl-mediated ubiquitinylation is required for lysosomal sorting of epidermal growth factor receptor but is dispensable for endocytosis. Journal of Biological Chemistry, 278(31), 28950-28960. https://doi.org/10.1074/jbc.M304474200