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
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Research Support, Non-U.S. Gov't
MeSH terms
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COP-Coated Vesicles / metabolism*
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COP-Coated Vesicles / ultrastructure
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Caenorhabditis elegans Proteins*
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Carrier Proteins / genetics
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Carrier Proteins / metabolism
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Cells, Cultured
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Cysteine Endopeptidases / metabolism
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Cysteine Endopeptidases / ultrastructure
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Endopeptidases / deficiency*
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Endopeptidases / genetics
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Endopeptidases / metabolism
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Endoplasmic Reticulum / metabolism
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Endoplasmic Reticulum / ultrastructure
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GTPase-Activating Proteins
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Galactosyltransferases / deficiency*
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Galactosyltransferases / genetics
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Golgi Apparatus / metabolism
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Golgi Apparatus / ultrastructure
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Microscopy, Electron
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Multienzyme Complexes / metabolism
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Multienzyme Complexes / ultrastructure
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Proteasome Endopeptidase Complex
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Protein Transport / physiology
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae / ultrastructure
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism*
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Ubiquitin / metabolism*
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Ubiquitin Thiolesterase
Substances
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Caenorhabditis elegans Proteins
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Carrier Proteins
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GTPase-Activating Proteins
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Multienzyme Complexes
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SEC23 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins
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USP10 protein, human
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Ubiquitin
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BRE-5 protein, C elegans
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Galactosyltransferases
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Endopeptidases
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Ubiquitin Thiolesterase
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Cysteine Endopeptidases
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Proteasome Endopeptidase Complex
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UBP3 protein, S cerevisiae