Bernardi KM, et al. (2013) A deubiquitinase negatively regulates retro-translocation of nonubiquitinated substrates. Mol Biol Cell 24(22):3545-56
Abstract: Endoplasmic reticulum (ER) membrane-bound E3 ubiquitin ligases promote ER-associated degradation (ERAD) by ubiquitinating a retro-translocated substrate that reaches the cytosol from the ER, targeting it to the proteasome for destruction. Recent findings implicate ERAD-associated deubiquitinases (DUBs) as positive and negative regulators during ERAD, reflecting the different consequences of deubiquitinating a substrate prior to proteasomal degradation. These observations raise the question of whether a DUB can control the fate of a nonubiquitinated ERAD substrate. In this study, we probed the role of the ERAD-associated DUB, YOD1, during retro-translocation of the nonubiquitinated cholera toxin A1 (CTA1) peptide, a critical intoxication step. Through combining knockdown, overexpression, and binding studies, we demonstrated that YOD1 negatively controls CTA1 retro-translocation, likely by deubiquitinating and inactivating ubiquitinated ERAD components that normally promote toxin retro-translocation. YOD1 also antagonizes the proteasomal degradation of nonglycosylated pro-a factor, a postulated nonubiquitinated yeast ERAD substrate, in mammalian cells. Our findings reveal that a cytosolic DUB exerts a negative function during retro-translocation of nonubiquitinated substrates, potentially by acting on elements of the ERAD machinery.
|Status: Published||Type: Journal Article||PubMed ID: 24068323|
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