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From Proteopedia
Saccharomyces cerevisiae Ufd1/Npl4/Cdc48 complex bound to two ubiquitin moieties and one unfolded ubiquitin in presence of SUMO-ubiquitin(K48polyUb)-mEOS and ATP, state 2 (uC)
Structural highlights
FunctionCDC48_YEAST ATP-dependent chaperone which probably uses the energy provided by ATP hydrolysis to generate mechanical force to unfold substrate proteins, disassemble protein complexes, and disaggregate protein aggregates (PubMed:21454554). By recruiting and promoting the degradation of ubiquitinated proteins, plays a role in the ubiquitin fusion degradation (UFD) pathway (PubMed:16428438). Has a role in the endoplasmic reticulum-associated degradation (ERAD) pathway which mediates the cytoplasmic elimination of misfolded proteins exported from the ER (PubMed:11813000, PubMed:11740563, PubMed:11847109, PubMed:21148305). Required for the proteasome-dependent processing/activation of MGA2 and SPT23 transcription factors leading to the subsequent expression of OLE1 (PubMed:11847109, PubMed:11733065). Has an additional role in the turnover of OLE1 where it targets ubiquitinated OLE1 and other proteins to the ERAD (PubMed:11847109). Regulates ubiquitin-mediated mitochondria protein degradation (PubMed:21070972, PubMed:27044889). Involved in spindle disassembly probably by promoting the degradation of spindle assembly factors ASE1 and CDC5 at the end of mitosis (PubMed:14636562). Component of the ribosome quality control complex (RQC), a ribosome-associated complex that mediates ubiquitination and extraction of incompletely synthesized nascent chains for proteasomal degradation (PubMed:23178123, PubMed:24261871). CDC48 may provide the mechanical force that dislodges the polyubiquitinated nascent peptides from the exit channel (PubMed:23178123, PubMed:24261871). Required for ribophagy, a process which relocalizes ribosomal particles into the vacuole for degradation in response to starvation (PubMed:20508643).[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] Publication Abstract from PubMedThe Ufd1/Npl4/Cdc48 complex is a universal protein segregase that plays key roles in eukaryotic cellular processes. Its functions orchestrating the clearance or removal of polyubiquitylated targets are established; however, prior studies suggest that the complex also targets substrates modified by the ubiquitin-like protein SUMO. Here, we show that interactions between Ufd1 and SUMO enhance unfolding of substrates modified by SUMO-polyubiquitin hybrid chains by the budding yeast Ufd1/Npl4/Cdc48 complex compared to substrates modified by polyubiquitin chains, a difference that is accentuated when the complex has a choice between these substrates. Incubating Ufd1/Npl4/Cdc48 with a substrate modified by a SUMO-polyubiquitin hybrid chain produced a series of single-particle cryo-EM structures that reveal features of interactions between Ufd1/Npl4/Cdc48 and ubiquitin prior to and during unfolding of ubiquitin. These results are consistent with cellular functions for SUMO and ubiquitin modifications and support a physical model wherein Ufd1/Npl4/Cdc48, SUMO, and ubiquitin conjugation pathways converge to promote clearance of proteins modified with SUMO and polyubiquitin. SUMO enhances unfolding of SUMO-polyubiquitin-modified substrates by the Ufd1/Npl4/Cdc48 complex.,Lee HG, Lemmon AA, Lima CD Proc Natl Acad Sci U S A. 2023 Jan 3;120(1):e2213703120. doi: , 10.1073/pnas.2213703120. Epub 2022 Dec 27. PMID:36574706[14] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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