Ubiquitin- A nd ATP-dependent unfoldase activity of P97/VCP•NPLOC4•UFD1L is enhanced by a mutation that causes multisystem proteinopathy

Emily E. Blythe, Kristine C. Olson, Vincent Chau, Raymond J. Deshaies

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P97 is a "segregase" that plays a key role in numerous ubiquitin (Ub)-dependent pathways such as ER-associated degradation. It has been hypothesized that p97 extracts proteins from membranes or macromolecular complexes to enable their proteasomal degradation; however, the complex nature of p97 substrates has made it difficult to directly observe the fundamental basis for this activity. To address this issue, we developed a soluble p97 substrate-Ub-GFP modified with K48-linked ubiquitin chains-for in vitro p97 activity assays. We demonstrate that WT p97 can unfold proteins and that this activity is dependent on the p97 adaptor NPLOC4-UFD1L, ATP hydrolysis, and substrate ubiquitination, with branched chains providing maximal stimulation. Furthermore, we show that a p97 mutant that causes inclusion body myopathy, Paget's disease of bone, and frontotemporal dementia in humans unfolds substrate faster, suggesting that excess activity may underlie pathogenesis. This work overcomes a significant barrier in the study of p97 and will allow the future dissection of p97 mechanism at a level of detail previously unattainable.

Original languageEnglish (US)
Pages (from-to)E4380-E4388
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number22
StatePublished - May 30 2017

All Science Journal Classification (ASJC) codes

  • General

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