Wang Qing, Song Changcheng, Li Chou-Chi H
Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, MD 21702, USA.
Biochem Biophys Res Commun. 2003 Jan 10;300(2):253-60. doi: 10.1016/s0006-291x(02)02840-1.
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.
97千道尔顿含缬酪肽蛋白（p97-VCP或VCP），一种六聚体AAA型ATP酶，在多种细胞活动中发挥重要作用，包括泛素-蛋白酶体介导的蛋白质降解。在本报告中，我们研究了解离-重组动力学以分析VCP中的结构-功能关系。尿素解离的VCP可自行重组，但添加ATP、ADP或ATP-γ-S可加速重组。D1结构域而非D2结构域的ATP结合位点突变消除了ATP加速作用并进一步延迟了重组。使用野生型和ATP结合位点突变体构建的杂合六聚体，我们发现六聚体结构以及亚基之间的适当通讯对于ATP酶活性和泛素-蛋白酶体介导的降解是必需的。因此，D1中的ATP结合位点在VCP六聚化中起主要作用，其中适当的亚基间相互作用对于这些活性至关重要。
