Pal Mohinder, Morgan Marc, Phelps Sarah E L, Roe S Mark, Parry-Morris Sarah, Downs Jessica A, Polier Sigrun, Pearl Laurence H, Prodromou Chrisostomos
MRC Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
MRC Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
Structure. 2014 Jun 10;22(6):805-18. doi: 10.1016/j.str.2014.04.001. Epub 2014 May 1.
Client protein recruitment to the Hsp90 system depends on cochaperones that bind the client and Hsp90 simultaneously and facilitate their interaction. Hsp90 involvement in the assembly of snoRNPs, RNA polymerases, PI3-kinase-like kinases, and chromatin remodeling complexes depends on the TTT (Tel2-Tti1-Tti2), and R2TP complexes-consisting of the AAA-ATPases Rvb1 and Rvb2, Tah1 (Spagh/RPAP3 in metazoa), and Pih1 (Pih1D1 in humans)-that together provide the connection to Hsp90. The biochemistry underlying R2TP function is still poorly understood. Pih1 in particular, at the heart of the complex, has not been described at a structural level, nor have the multiple protein-protein interactions it mediates been characterized. Here we present a structural and biochemical analysis of Hsp90-Tah1-Pih1, Hsp90-Spagh, and Pih1D1-Tel2 complexes that reveal a domain in Pih1D1 specific for binding CK2 phosphorylation sites, and together define the structural basis by which the R2TP complex connects the Hsp90 chaperone system to the TTT complex.
客户蛋白招募到热休克蛋白90（Hsp90）系统依赖于共伴侣蛋白，这些共伴侣蛋白同时结合客户蛋白和Hsp90，并促进它们之间的相互作用。Hsp90参与小核仁核糖核蛋白（snoRNPs）、RNA聚合酶、磷脂酰肌醇-3激酶样激酶和染色质重塑复合物的组装，依赖于TTT（Tel2-Tti1-Tti2）以及R2TP复合物，R2TP复合物由AAA-ATP酶Rvb1和Rvb2、Tah1（后生动物中的Spagh/RPAP3）和Pih1（人类中的Pih1D1）组成，它们共同提供了与Hsp90的连接。R2TP功能的潜在生物化学机制仍知之甚少。特别是位于复合物核心的Pih1，尚未在结构层面上被描述，其介导的多种蛋白质-蛋白质相互作用也未得到表征。在这里，我们展示了对Hsp90-Tah1-Pih1、Hsp90-Spagh和Pih1D1-Tel2复合物的结构和生物化学分析，这些分析揭示了Pih1D1中一个特定于结合CK2磷酸化位点的结构域，并共同确定了R2TP复合物将Hsp90伴侣系统与TTT复合物连接起来的结构基础。
