title: Hexamerization of p97-VCP is promoted by ATP binding to the D1 domain and required for ATPase and biological activities.
abstract: The 97-kDa valosin-containing protein (p97-VCP or VCP), a hexameric AAA ATPase, plays an important role in diverse cell activities, including ubiquitin-proteasome mediated protein degradation. In this report, we studied dissociation-reassembly kinetics to analyze the structure-function relationship in VCP. Urea-dissociated VCP can reassemble by itself, but addition of ATP, ADP, or ATP-gamma S accelerates the reassembly. Mutation in the ATP-binding site of D1, but not D2, domain abolishes the ATP acceleration effect and further delays the reassembly. Using hybrid hexamers of the wild type and ATP-binding site mutant, we show that hexameric structure and proper communication among the subunits are required for the ATPase activity and ubiquitin-proteasome mediated degradation. Thus, ATP-binding site in D1 plays a major role in VCP hexamerization, of which proper inter-subunit interaction is essential for the activities.
authors.affiliation: Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, MD 21702, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.forename: Changcheng
authors.initials: C
authors.lastname: Song
authors.forename: Chou-Chi H
authors.initials: CC
authors.lastname: Li
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D003546:Cysteine Endopeptidases / Q000378:metabolism; D007700:Kinetics; D009097:Multienzyme Complexes / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D046988:Proteasome Endopeptidase Complex; D011489:Protein Denaturation; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D013329:Structure-Activity Relationship; D025801:Ubiquitin / Q000378:metabolism; D014508:Urea / Q000494:pharmacology; D000074405:Valosin Containing Protein
chemical_list: D018797:Cell Cycle Proteins; D009097:Multienzyme Complexes; D021122:Protein Subunits; D025801:Ubiquitin; D000255:Adenosine Triphosphate; D014508:Urea; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases; D000074405:Valosin Containing Protein