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Cryo-EM structure of p97:UBXD1 VIM-only state
Structural highlights
FunctionUBXN6_HUMAN May negatively regulate the ATPase activity of VCP, an ATP-driven segregase that associates with different cofactors to control a wide variety of cellular processes (PubMed:26475856). As a cofactor of VCP, it may play a role in the transport of CAV1 to lysosomes for degradation (PubMed:21822278, PubMed:23335559). It may also play a role in endoplasmic reticulum-associated degradation (ERAD) of misfolded proteins (PubMed:19275885). Together with VCP and other cofactors, it may play a role in macroautophagy, regulating for instance the clearance of damaged lysosomes (PubMed:27753622).[1] [2] [3] [4] [5] Publication Abstract from PubMedp97/VCP is an essential cytosolic AAA+ ATPase hexamer that extracts and unfolds substrate polypeptides during protein homeostasis and degradation. Distinct sets of p97 adapters guide cellular functions but their roles in direct control of the hexamer are unclear. The UBXD1 adapter localizes with p97 in critical mitochondria and lysosome clearance pathways and contains multiple p97-interacting domains. We identify UBXD1 as a potent p97 ATPase inhibitor and report structures of intact p97:UBXD1 complexes that reveal extensive UBXD1 contacts across p97 and an asymmetric remodeling of the hexamer. Conserved VIM, UBX, and PUB domains tether adjacent protomers while a connecting strand forms an N-terminal domain lariat with a helix wedged at the interprotomer interface. An additional VIM-connecting helix binds along the second AAA+ domain. Together these contacts split the hexamer into a ring-open conformation. Structures, mutagenesis, and comparisons to other adapters further reveal how adapters containing conserved p97-remodeling motifs regulate p97 ATPase activity and structure. The p97/VCP adapter UBXD1 drives AAA+ remodeling and ring opening through multi-domain tethered interactions.,Braxton JR, Altobelli CR, Tucker MR, Tse E, Thwin AC, Arkin MR, Southworth DR bioRxiv. 2023 May 15:2023.05.15.540864. doi: 10.1101/2023.05.15.540864. Preprint. PMID:37292947[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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