6jwi
From Proteopedia
Yeast Npl4 in complex with Lys48-linked diubiquitin
Structural highlights
Function[NPL4_YEAST] Involved in the import of nuclear-targeted proteins into the nucleus and the export of poly(A) RNA out of the nucleus (PubMed:8930904, PubMed:11733065). Has a role in the endoplasmic reticulum-associated degradation (ERAD) pathway (PubMed:11739805, PubMed:11740563, PubMed:11847109). Required for the proteasome-dependent processing/activation of MGA2 and SPT23 transcription factors leading to the subsequent expression of OLE1 (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). Involved in spindle disassembly probably by promoting the degradation of spindle assemby factors ASE1 and CDC5 at the end of mitosis (PubMed:14636562).[1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedNpl4 is likely to be the most upstream factor recognizing Lys48-linked polyubiquitylated substrates in the proteasomal degradation pathway in yeast. Along with Ufd1, Npl4 forms a heterodimer (UN), and functions as a cofactor for the Cdc48 ATPase. Here, we report the crystal structures of yeast Npl4 in complex with Lys48-linked diubiquitin and with the Npl4-binding motif of Ufd1. The distal and proximal ubiquitin moieties of Lys48-linked diubiquitin primarily interact with the C-terminal helix and N-terminal loop of the Npl4 C-terminal domain (CTD), respectively. Mutational analysis suggests that the CTD contributes to linkage selectivity and initial binding of ubiquitin chains. Ufd1 occupies a hydrophobic groove of the Mpr1/Pad1 N-terminal (MPN) domain of Npl4, which corresponds to the catalytic groove of the MPN domain of JAB1/MPN/Mov34 metalloenzyme (JAMM)-family deubiquitylating enzyme. This study provides important structural insights into the polyubiquitin chain recognition by the Cdc48-UN complex and its assembly. Structural insights into ubiquitin recognition and Ufd1 interaction of Npl4.,Sato Y, Tsuchiya H, Yamagata A, Okatsu K, Tanaka K, Saeki Y, Fukai S Nat Commun. 2019 Dec 13;10(1):5708. doi: 10.1038/s41467-019-13697-y. PMID:31836717[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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