Multisystem Proteinopathy Mutations in VCP/p97 Increase NPLOC4.UFD1L Binding and Substrate Processing
Multisystem Proteinopathy Mutations in VCP/p97 Increase NPLOC4.UFD1L Binding and Substrate Processing
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DOI：
10.1016/j.str.2019.09.011
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发表时间：
2019-12-03
期刊：
影响因子：
5.7
通讯作者：
Martin, Andreas
中科院分区：
文献类型：
--
作者：
Blythe, Emily E.;Gates, Stephanie N.;Martin, Andreas
Valosin 含蛋白 (VCP)/p97 是一种必需的 ATP 依赖性蛋白解折叠酶。 p97 的显性突变会导致多系统蛋白病 (MSP)，这是一种影响大脑、肌肉和骨骼的疾病。尽管已鉴定出 MSP 中受到干扰的许多途径，但这些 p97 突变体的分子水平缺陷尚未完全了解。在这里，我们使用生物化学和冷冻电子显微镜来探讨 MSP 突变对 p97 与其底物适配器 NPLOC4.UFD1L (UN) 复合物的解折叠酶活性的影响。我们发现所有七个分析的 MSP 突变体都能更快地展开底物。突变的同源六聚体和异源六聚体表现出更紧密的 UN 结合和更快的底物处理。我们的结构研究表明，UN 亲和力的增加源于 p97 核苷酸状态的解偶联及其 N 末端结构域的定位。总之，我们的数据支持 MSP 中 p97-UN 依赖性过程的功能获得模型，并强调 N 端结构域移动对于 p97 的接头招募和底物处理的重要性。
Valosin-containing protein (VCP)/p97 is an essential ATP-dependent protein unfoldase. Dominant mutations in p97 cause multisystem proteinopathy (MSP), a disease affecting the brain, muscle, and bone. Despite the identification of numerous pathways that are perturbed in MSP, the molecular-level defects of these p97 mutants are not completely understood. Here, we use biochemistry and cryoelectron microscopy to explore the effects of MSP mutations on the unfoldase activity of p97 in complex with its substrate adaptor NPLOC4.UFD1L (UN). We show that all seven analyzed MSP mutants unfold substrates faster. Mutant homo- and heterohexamers exhibit tighter UN binding and faster substrate processing. Our structural studies suggest that the increased UN affinity originates from a decoupling of p97's nucleotide state and the positioning of its N-terminal domains. Together, our data support a gain-of-function model for p97-UN-dependent processes in MSP and underscore the importance of N-terminal domain movements for adaptor recruitment and substrate processing by p97.