title: Altered cofactor regulation with disease-associated p97/VCP mutations.
abstract: 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 (kcat/Km) of p97 by 11-fold. Whereas both p37 and p47 decrease the Km of ATP in p97, p37 increases the kcat of p97. In contrast, regulation by p47 is biphasic, with decreased kcat at low levels but increased kcat 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.
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Harbor-UCLA Medical Center, Los Angeles Biomedical Research Institute, Torrance, CA 90502; College of Pharmaceutical Sciences, Capital Medical University, Beijing 100069, People's Republic of China;
authors.forename: Xiaoyi
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Harbor-UCLA Medical Center, Los Angeles Biomedical Research Institute, Torrance, CA 90502; College of Pharmaceutical Sciences, Capital Medical University, Beijing 100069, People's Republic of China;
authors.forename: Lin
authors.initials: L
authors.lastname: Gui
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, The University of Michigan, Ann Arbor, MI 48109-1048;
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Small Molecule Discovery Center, Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158;
authors.forename: Stacie L
authors.initials: SL
authors.lastname: Bulfer
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Harbor-UCLA Medical Center, Los Angeles Biomedical Research Institute, Torrance, CA 90502;
authors.forename: Valentina
authors.initials: V
authors.lastname: Sanghez
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Harbor-UCLA Medical Center, Los Angeles Biomedical Research Institute, Torrance, CA 90502;
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Wong
authors.affiliation: Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110;
authors.forename: YouJin
authors.initials: Y
authors.lastname: Lee
authors.affiliation: NanoTemper Technologies, Inc., South San Francisco, CA 94080;
authors.forename: Lynn
authors.initials: L
authors.lastname: Lehmann
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125.
authors.forename: James Siho
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125.
authors.forename: Pei-Yin
authors.initials: PY
authors.lastname: Shih
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Harbor-UCLA Medical Center, Los Angeles Biomedical Research Institute, Torrance, CA 90502;
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Lin
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Harbor-UCLA Medical Center, Los Angeles Biomedical Research Institute, Torrance, CA 90502;
authors.forename: Michelina
authors.initials: M
authors.lastname: Iacovino
authors.affiliation: Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110;
authors.forename: Conrad C
authors.initials: CC
authors.lastname: Weihl
authors.affiliation: Small Molecule Discovery Center, Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158;
authors.forename: Michelle R
authors.initials: MR
authors.lastname: Arkin
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, The University of Michigan, Ann Arbor, MI 48109-1048;
authors.forename: Yanzhuang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Harbor-UCLA Medical Center, Los Angeles Biomedical Research Institute, Torrance, CA 90502; tsuifenchou@ucla.edu.
authors.forename: Tsui-Fen
authors.initials: TF
authors.lastname: Chou
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D001343:Autophagy; D001847:Bone Diseases / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D002850:Chromatography, Gel; D006056:Golgi Apparatus; D006706:Homeostasis; D006801:Humans; D009135:Muscular Diseases / Q000378:metabolism; D009154:Mutation; D019636:Neurodegenerative Diseases / Q000378:metabolism; D010641:Phenotype; D017434:Protein Structure, Tertiary; D020349:Surface Plasmon Resonance; D000074405:Valosin Containing Protein
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; C553975:p37 protein, human; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C000614178:VCP protein, human; D000074405:Valosin Containing Protein
keywords: AAA ATPase; MSP1; p47; p97/VCP; steady-state kinetics