Structure and Regulation of hsp90 Chaperones

hsp90 分子伴侣的结构和调控

• 批准号: 7057794
• 负责人: DANIEL T GEWIRTH
• 金额: $ 30.9万
• 依托单位: HAUPTMAN-WOODWARD MEDICAL RESEARCH INST
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7057794
• 关键词: X ray crystallography; conformation; endoplasmic reticulum; heat shock proteins; ligands; molecular chaperones; nuclear magnetic resonance spectroscopy; peptide chemical synthesis; protein binding; protein protein interaction; protein structure function; site directed mutagenesis; small molecule; stereochemistry

DESCRIPTION (provided by applicant): The hsp90 chaperones participate in the maturation of proteins involved in diverse cellular activities ranging from signaling to bacterial recognition. They are also key players in the response to cell stress events. Cytoplasmic Hsp90s guide the maturation of steroid hormone receptors and proto-oncogenic kinases, and hsp90 inhibitors disrupt this maturation and display potent anti-cancer activity. GRP94, the ER hsp90 paralog, chaperones proteins destined for transport to the cell surface, including the Toll-like receptors. Cells deficient in GRP94 are unresponsive to microbial stimuli. GRP94 has also been identified as a tumor rejection antigen and elicits suppression of tumor growth and metastasis. The activity of hsp90 chaperones is regulated by small molecule ligands such as ATP that bind to the N-terminal domain, as well as by their conformational state. Key questions that remain unanswered include how ligands exert their inhibitory or activation effects, how different hsp90 paralogs are selectively regulated, how changes in conformation lead to altered activity, and how client proteins interact with the chaperone. An understanding of the stereochemistry that underlies hsp90 biology and hsp90-targeted therapies requires the structural analysis of the relevant macromolecular species. Using X-ray crystallography, NMR spectroscopy, and biochemical- and cell-based assays, the experiments in this proposal will address how GRP94 is regulated by small molecule ligands and interacts with client proteins. We will solve and analyze the structure of the N-terminal domain of GRP94 alone and in complex with activators, broad-spectrum antagonists, and selective inhibitors. Novel selective inhibitors of GRP94 will be designed and synthesized based on these structures. We also propose to examine the interaction of GRP94 with peptides, building on recent work that identified a peptide-binding site in the N-domain. We also plan to investigate the structural basis for N-domain dimerization and oligomerization by constructing GRP94 and Hsp90 molecules lacking candidate interacting elements and determining their functional properties. Finally, the structures of multi-domain GRP94 constructs, including full-length variants, alone or in complex with client proteins will be determined in order to understand the interplay between the domains and the mechanism of substrate interaction. Structural findings will be correlated with measurements of ligand affinity and chaperone activity in both wild-type and mutationally altered molecules.

描述（由申请人提供）：hsp90伴侣参与多种细胞活动（从信号传导到细菌识别）中涉及的蛋白质成熟。它们也是对细胞应激事件的反应的关键参与者。细胞质hsp90引导类固醇激素受体和原致癌激酶的成熟，而hsp90抑制剂破坏这种成熟并显示出有效的抗癌活性。GRP94， ER hsp90类似物，伴侣蛋白被运输到细胞表面，包括toll样受体。缺乏GRP94的细胞对微生物刺激无反应。GRP94也被认为是一种肿瘤排斥抗原，可以抑制肿瘤的生长和转移。