Ubp3 requires a cofactor, Bre5, to specifically de-ubiquitinate the COPII protein, Sec23.
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.
Cohen
Mickaël
M
Nucleocytoplasmic transport group, Institut Jacques Monod., Unité Mixte de Recherche 7592, CNRS, Universités Paris VI and VII, 2 Place Jussieu. Tour 43. 75251, Paris, Cedex 05, France.
Stutz
Françoise
F
Belgareh
Naïma
N
Haguenauer-Tsapis
Rosine
R
Dargemont
Catherine
C
D022181:COP-Coated Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases / Q000378:metabolism / Q000648:ultrastructure; D010450:Endopeptidases / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000648:ultrastructure; D020690:GTPase-Activating Proteins; D005700:Galactosyltransferases / Q000172:deficiency* / Q000235:genetics; D006056:Golgi Apparatus / Q000378:metabolism / Q000648:ultrastructure; D008854:Microscopy, Electron; D009097:Multienzyme Complexes / Q000378:metabolism / Q000648:ultrastructure; D046988:Proteasome Endopeptidase Complex; D021381:Protein Transport / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism*; D043222:Ubiquitin Thiolesterase
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D020690:GTPase-Activating Proteins; D009097:Multienzyme Complexes; C079037:SEC23 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C431363:USP10 protein, human; D025801:Ubiquitin; C433229:BRE-5 protein, C elegans; D005700:Galactosyltransferases; D010450:Endopeptidases; D043222:Ubiquitin Thiolesterase; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; C101111:UBP3 protein, S cerevisiae