Abstract
Rsp5, the Nedd4 family member in yeast, is an E3 ubiquitin ligase involved in numerous cellular processes, many of which require Rsp5 to interact with PY-motif containing adaptor proteins. Here, we show that two paralogous transmembrane Rsp5 adaptors, Rcr1 and Rcr2, are sorted to distinct cellular locations: Rcr1 is a plasma membrane (PM) protein, whereas Rcr2 is sorted to the vacuole. Rcr2 is delivered to the vacuole using ubiquitin as a sorting signal. Rcr1 is delivered to the PM by the exomer complex using a newly uncovered PM sorting motif. Further, we show that Rcr1, but not Rcr2, is up-regulated via the calcineurin/Crz1 signaling pathway. Upon exogenous calcium treatment, Rcr1 ubiquitinates and down-regulates the chitin synthase Chs3. We propose that the PM-anchored Rsp5/Rcr1 ubiquitin ligase-adaptor complex can provide an acute response to degrade unwanted proteins under stress conditions, thereby maintaining cell integrity.
© 2020 Zhu et al.
MeSH terms
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Calcineurin / genetics
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Calcineurin / metabolism*
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Chitin Synthase / genetics
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Chitin Synthase / metabolism
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Endocytosis*
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Endosomal Sorting Complexes Required for Transport / genetics
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Endosomal Sorting Complexes Required for Transport / metabolism*
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Gene Expression Regulation, Fungal
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Membrane Proteins / genetics
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Membrane Proteins / metabolism*
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Protein Sorting Signals
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Proteolysis
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism*
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Signal Transduction
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Ubiquitin-Protein Ligase Complexes / genetics
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Ubiquitin-Protein Ligase Complexes / metabolism*
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Ubiquitination
Substances
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CNB1 protein, S cerevisiae
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CRZ1 protein, S cerevisiae
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DNA-Binding Proteins
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Endosomal Sorting Complexes Required for Transport
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Membrane Proteins
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Protein Sorting Signals
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Rcr1 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins
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Transcription Factors
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Ubiquitin-Protein Ligase Complexes
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CHS3 protein, S cerevisiae
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Chitin Synthase
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Calcineurin
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RSP5 protein, S cerevisiae