Nucleotide-dependent interaction of Saccharomyces cerevisiae Hsp90 with the cochaperone proteins Sti1, Cpr6, and Sba1
Nucleotide-dependent interaction of Saccharomyces cerevisiae Hsp90 with the cochaperone proteins Sti1, Cpr6, and Sba1
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DOI：
10.1128/mcb.01034-06
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发表时间：
2007-01-01
影响因子：
5.3
通讯作者：
Flom, Gary
中科院分区：
文献类型：
--
作者：
Johnson, Jill L.;Halas, Agnieszka;Flom, Gary
ATP依赖性分子伴侣Hsp 90和伴侣辅伴侣蛋白是多种细胞客户蛋白（包括类固醇激素受体和多种致癌激酶）的折叠和活性所必需的。热休克蛋白90经历核苷酸依赖的构象变化，但很少有人知道这些变化是如何耦合到客户端蛋白激活。为了阐明核苷酸如何影响热休克蛋白90与辅伴侣蛋白的相互作用，我们监测了野生型和突变型热休克蛋白90与酿酒酵母细胞提取物中的Stil，Sba 1和Cpr 6的组装。野生型热休克蛋白90结合斯蒂尔在一个核苷酸独立的方式，而Sba 1和Cpr 6特异性和独立的相互作用与热休克蛋白90的存在下，ATP，AMP-PNP的非水解类似物。Hsp 90残基的改变，有助于ATP的结合或水解阻止或改变Sba 1和Cpr 6的相互作用;额外的改变影响Cpr 6相互作用的特异性。Hsp 90的一些突变形式在存在核苷酸的情况下也显示出Stil相互作用的减少。这些研究表明，Hsp 90之间的核苷酸自由，开放的构象和ATP结合，封闭的构象的循环是由N-末端ATP酶结构域内外的残基的影响，这些构象的变化有显着的影响与辅伴侣蛋白的相互作用。
The ATP-dependent molecular chaperone Hsp90 and partner cochaperone proteins are required for the folding and activity of diverse cellular client proteins, including steroid hormone receptors and multiple oncogenic kinases. Hsp90 undergoes nucleotide-dependent conformational changes, but little is known about how these changes are coupled to client protein activation. In order to clarify how nucleotides affect Hsp90 interactions with cochaperone proteins, we monitored assembly of wild-type and mutant Hsp90 with Stil, Sba1, and Cpr6 in Saccharomyces cerevisiae cell extracts. Wild-type Hsp90 bound Stil in a nucleotide-independent manner, while Sba1 and Cpr6 specifically and independently interacted with Hsp90 in the presence of the nonhydrolyzable analog of ATP, AMP-PNP. Alterations in Hsp90 residues that contribute to ATP binding or hydrolysis prevented or altered Sba1 and Cpr6 interaction; additional alterations affected the specificity of Cpr6 interaction. Some mutant forms of Hsp90 also displayed reduced Stil interaction in the presence of a nucleotide. These studies indicate that cycling of Hsp90 between the nucleotide-free, open conformation and the ATP-bound, closed conformation is influenced by residues both within and outside the N-terminal ATPase domain and that these conformational changes have dramatic effects on interaction with cochaperone proteins.