Vps9p CUE domain ubiquitin binding is required for efficient endocytic protein traffic

Brian A. Davies, Justin D. Topp, Agnel J. Sfeir, David J. Katzmann, Darren S. Carney, Gregory G. Tall, Andrew S. Friedberg, Li Deng, Zhijian Chen, Bruce F. Horazdovsky

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


Rab5 GTPases are key regulators of protein trafficking through the early stages of the endocytic pathway. The yeast Rab5 ortholog Vps21p is activated by its guanine nucleotide exchange factor Vps9p. Here we show that Vps9p binds ubiquitin and that the CUE domain is necessary and sufficient for this interaction. Vps9p ubiquitin binding is required for efficient endocytosis of Ste3p but not for the delivery of the biosynthetic cargo carboxypeptidase Y to the vacuole. In addition, Vps9p is itself monoubiquitylated. Ubiquitylation is dependent on a functional CUE domain and Rsp5p, an E3 ligase that participates in cell surface receptor endocytosis. These findings define a new ubiquitin binding domain and implicate ubiquitin as a modulator of Vps9p function in the endocytic pathway.

Original languageEnglish (US)
Pages (from-to)19826-19833
Number of pages8
JournalJournal of Biological Chemistry
Issue number22
StatePublished - May 30 2003

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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