Atg19p ubiquitination and the cytoplasm to vacuole trafficking pathway in yeast

Bonnie K. Baxter, Hagai Abeliovich, Xin Zhang, Aline G. Stirling, Alma L. Burlingame, David S. Goldfarb*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


The cytoplasm to vacuole (Cvt) trafficking pathway in 5. cerevisiae is a constitutive biosynthetic pathway required for the transport of two vacuolar enzymes, aminopeptidase I (Ape1p) and α-mannosidase (Ams1p), to the vacuole. Ape1p and Ams1p bind to their receptor, Atg19p, in the cytosol to form a Cvt complex, which then associates with a membrane structure that envelops the complex before fusing with the vacuolar membrane. Ubiquitin-like modifications are required for both Cvt and macroautophagy, but no role for ubiquitin itself has been described. Here, we show that the deubiquitinating enzyme Ubp3p interacts with Atg19p. Moreover, Atg19p is ubiquitinated in vivo, and Atg19p-ubiquitin conjugates accumulate in cells lacking either Ubp3p or its cofactor, Bre5p. Deletion of UBP3 also leads to decreased targeting of Ape1p to the vacuole. Atg19p is ubiquitinated on two lysine residues, Lys213 and Lys216, which, when mutated, reduce the interaction of Atg19p with Ape1p. These results suggest that both ubiquitination and deubiquitination of Atg19p are required for its full function.

Original languageAmerican English
Pages (from-to)39067-39076
Number of pages10
JournalJournal of Biological Chemistry
Issue number47
StatePublished - 25 Nov 2005


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