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Published April 7, 2015 | Published + Supplemental Material
Journal Article Open

Altered cofactor regulation with disease-associated p97/VCP mutations


Dominant mutations in p97/VCP (valosin-containing protein) cause a rare multisystem degenerative disease with varied phenotypes that include inclusion body myopathy, Paget's disease of bone, frontotemporal dementia, and amyotrophic lateral sclerosis. p97 disease mutants have altered N-domain conformations, elevated ATPase activity, and altered cofactor association. We have now discovered a previously unidentified disease-relevant functional property of p97 by identifying how the cofactors p37 and p47 regulate p97 ATPase activity. We define p37 as, to our knowledge, the first known p97-activating cofactor, which enhances the catalytic efficiency (k_(cat)/K_m) of p97 by 11-fold. Whereas both p37 and p47 decrease the K_m of ATP in p97, p37 increases the k_(cat) of p97. In contrast, regulation by p47 is biphasic, with decreased k_(cat) at low levels but increased k_(cat) at higher levels. By deleting a region of p47 that lacks homology to p37 (amino acids 69–92), we changed p47 from an inhibitory cofactor to an activating cofactor, similar to p37. Our data suggest that cofactors regulate p97 ATPase activity by binding to the N domain. Induced conformation changes affect ADP/ATP binding at the D1 domain, which in turn controls ATPase cycling. Most importantly, we found that the D2 domain of disease mutants failed to be activated by p37 or p47. Our results show that cofactors play a critical role in controlling p97 ATPase activity, and suggest that lack of cofactor-regulated communication may contribute to p97-associated disease pathogenesis.

Additional Information

© 2015 National Academy of Sciences. Freely available online through the PNAS open access option. Edited by William J. Lennarz, Stony Brook University, Stony Brook, NY, and approved February 10, 2015 (received for review September 30, 2014) Published online before print March 16, 2015, doi: 10.1073/pnas.1418820112. T.-F.C. was in part supported by the National Center for Advancing Translational Sciences through UCLA Clinical Translational Science Institute (CTSI) Grant UL1TR000124 and the LA BioMed Seed Grant Program (20826-01). S.L.B. and M.R.A. were funded in part with federal funds from the National Cancer Institute, National Institutes of Health, under Contract HHSN261200800001E, through the NExT Chemical Biology Consortium. (The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the US Government.) Y.W. is supported in part by the National Institutes of Health (Grants GM087364 and GM105920), American Cancer Society (Grant RGS-09-278-01-CSM), MCubed, and the Fastforward Protein Folding Disease Initiative of The University of Michigan. C.C.W. is supported in part by the National Institutes of Health (Grants AG031867 and AG042095). T.-F.C. is a member of the UCLA Jonsson Comprehensive Cancer Center. Author contributions: Xiaoyi Zhang, L.G., Xiaoyan Zhang, S.L.B., Y.L., C.C.W., Y.W., and T.-F.C. designed research; Xiaoyi Zhang, L.G., Xiaoyan Zhang, S.L.B., D.E.W., Y.L., and L.L. performed research; V.S., C.C.W., Y.W., and T.-F.C. contributed new reagents/analytic tools; Xiaoyi Zhang, L.G., Xiaoyan Zhang, S.L.B., V.S., D.E.W., Y.L., L.L., J.S.L., P.-Y.S., H.J.L., M.I., C.C.W., M.R.A., Y.W., and T.-F.C. analyzed data; and S.L.B., D.E.W., J.S.L., P.-Y.S., H.J.L., M.I., C.C.W., M.R.A., Y.W., and T.-F.C. wrote the paper. The authors declare no conflict of interest. This article is a PNAS Direct Submission. This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1418820112/-/DCSupplemental.

Attached Files

Published - PNAS-2015-Zhang-E1705-14.pdf

Supplemental Material - pnas.1418820112.sapp.pdf


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August 22, 2023
August 22, 2023