Ubp3 requires a cofactor, Bre5, to specifically de-ubiquitinate the COPII protein, Sec23

Nat Cell Biol. 2003 Jul;5(7):661-7. doi: 10.1038/ncb1003.

Abstract

Ubiquitination is important for a broad array of cellular functions. Although reversal of this process, de-ubiquitination, most probably represents an important regulatory step contributing to cellular homeostasis, the specificity and properties of de-ubiquitination enzymes remain poorly understood. Here, we show that the Saccharomyces cerevisiae ubiquitin protease Ubp3 requires an additional protein, Bre5, to form an active de-ubiquitination complex that cleaves ubiquitin from specific substrates. In particular, this complex rescues Sec23p, a COPII subunit essential for the transport between the endoplasmic reticulum and the Golgi apparatus, from degradation by the proteasome. This probably contributes to maintaining and adapting a Sec23 expression level that is compatible with an efficient secretion pathway, and consequently with cell growth and viability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • COP-Coated Vesicles / metabolism*
  • COP-Coated Vesicles / ultrastructure
  • Caenorhabditis elegans Proteins*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Cells, Cultured
  • Cysteine Endopeptidases / metabolism
  • Cysteine Endopeptidases / ultrastructure
  • Endopeptidases / deficiency*
  • Endopeptidases / genetics
  • Endopeptidases / metabolism
  • Endoplasmic Reticulum / metabolism
  • Endoplasmic Reticulum / ultrastructure
  • GTPase-Activating Proteins
  • Galactosyltransferases / deficiency*
  • Galactosyltransferases / genetics
  • Golgi Apparatus / metabolism
  • Golgi Apparatus / ultrastructure
  • Microscopy, Electron
  • Multienzyme Complexes / metabolism
  • Multienzyme Complexes / ultrastructure
  • Proteasome Endopeptidase Complex
  • Protein Transport / physiology
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae / ultrastructure
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Ubiquitin / metabolism*
  • Ubiquitin Thiolesterase

Substances

  • Caenorhabditis elegans Proteins
  • Carrier Proteins
  • GTPase-Activating Proteins
  • Multienzyme Complexes
  • SEC23 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • USP10 protein, human
  • Ubiquitin
  • BRE-5 protein, C elegans
  • Galactosyltransferases
  • Endopeptidases
  • Ubiquitin Thiolesterase
  • Cysteine Endopeptidases
  • Proteasome Endopeptidase Complex
  • UBP3 protein, S cerevisiae