Client Proteins and Small Molecule Inhibitors Display Distinct Binding Preferences for Constitutive and Stress-Induced HSP90 Isoforms and Their Conformationally Restricted Mutants.
Client Proteins and Small Molecule Inhibitors Display Distinct Binding Preferences for Constitutive and Stress-Induced HSP90 Isoforms and Their Conformationally Restricted Mutants.
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DOI：
10.1371/journal.pone.0141786
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Neckers L
中科院分区：
文献类型：
--
作者：
Prince TL;Kijima T;Tatokoro M;Lee S;Tsutsumi S;Yim K;Rivas C;Alarcon S;Schwartz H;Khamit-Kush K;Scroggins BT;Beebe K;Trepel JB;Neckers L
分子伴侣 HSP90 的两种胞质/核亚型、应激诱导型 HSP90α 和组成型表达的 HSP90β，折叠、组装并维持众多客户蛋白的三维结构。由于许多 HSP90 客户在癌症中很重要，因此已经在临床中评估了几种 HSP90 抑制剂。然而，对于个体 HSP90 客户或抑制剂可能独特的异构体或构象偏好知之甚少。在本报告中，我们比较了 HSP90α 和 HSP90β 与转录因子 HSF1 和 HIF1α、激酶 ERBB2 和 MET、E3 泛素连接酶 KEAP1 和 RHOBTB2 以及 HSP90 抑制剂格尔德霉素和 ganetespib 的相对相互作用强度。我们观察到两种 HSP90 同工型的相对客户和药物偏好存在意想不到的差异，与 HSP90β 相比，HSP90α 与每种客户蛋白的结合具有更大的表观亲和力，而与 HSP90α 相比，HSP90β 与每种抑制剂的相对相互作用强度更大。稳定的 HSP90 相互作用与客户活动的减少相关。使用一组定义的 HSP90 构象突变体，我们发现一些客户端与单个 ATP 稳定的 HSP90 构象强烈相互作用，仅在动态 HSP90 伴侣循环期间短暂填充，而其他客户端与多个 HSP90 构象同等地相互作用。这些数据表明 HSP90 客户之间存在不同的功能需求，对于某些客户来说，这些功能需求可能与 ATP 无关。最后，所检查的两种抑制剂虽然共享相同的结合位点，但获得不同 HSP90 构象状态的能力不同。
The two cytosolic/nuclear isoforms of the molecular chaperone HSP90, stress-inducible HSP90α and constitutively expressed HSP90β, fold, assemble and maintain the three-dimensional structure of numerous client proteins. Because many HSP90 clients are important in cancer, several HSP90 inhibitors have been evaluated in the clinic. However, little is known concerning possible unique isoform or conformational preferences of either individual HSP90 clients or inhibitors. In this report, we compare the relative interaction strength of both HSP90α and HSP90β with the transcription factors HSF1 and HIF1α, the kinases ERBB2 and MET, the E3-ubiquitin ligases KEAP1 and RHOBTB2, and the HSP90 inhibitors geldanamycin and ganetespib. We observed unexpected differences in relative client and drug preferences for the two HSP90 isoforms, with HSP90α binding each client protein with greater apparent affinity compared to HSP90β, while HSP90β bound each inhibitor with greater relative interaction strength compared to HSP90α. Stable HSP90 interaction was associated with reduced client activity. Using a defined set of HSP90 conformational mutants, we found that some clients interact strongly with a single, ATP-stabilized HSP90 conformation, only transiently populated during the dynamic HSP90 chaperone cycle, while other clients interact equally with multiple HSP90 conformations. These data suggest different functional requirements among HSP90 clientele that, for some clients, are likely to be ATP-independent. Lastly, the two inhibitors examined, although sharing the same binding site, were differentially able to access distinct HSP90 conformational states.