Nanoscale mechanisms of Hsp90 and its co-chaperones

描述(申请人提供)：许多癌症是由正常蛋白质的突变版本的异常活性引起的，这些突变版本的正常蛋白质严重依赖‘分子伴侣’Hsp90进行折叠。HSP90不是单独作用的，而是与多蛋白组合中的HSP90、HSP70、HOP和CHIP结合在一起。这些关联是由被称为TPR的基序调节的。这项提议的目标是开发一种基于原子力显微镜(AFM)成像的分析方法，使人们能够详细研究这些纳米级复合体的组装。利用生物素化的HOP和Streptavidin表面，将研究Hsp90-Hop-Hsp70组合体，并在原位和实时监测它们的形成。此外，使用相同的基于AFM的分析，将阐明CHIP的作用及其与Hsp90-HOP-HSP70组装相互作用的性质。最后，本试验将用于了解更紧密的结合TPR和小分子的影响，它们能够抑制Hsp90-HOP-Hsp70的形成。这些新颖的研究将使对这些纳米级工艺和组装的理解达到一个新的水平。它们与癌症有直接的关系，因为抑制Hsp90的活性是一条被证明是抗癌治疗的途径。

DESCRIPTION (provided by applicant): Many cancers are caused by the aberrant activity of mutant versions of normal proteins, which are critically dependent on the 'molecular chaperone' Hsp90 for folding. Hsp90 does not act alone, but associates with the proteins Hsp90, Hsp70, HOP and CHIP in multi-protein assemblies. These associations are mediated by motifs called TPRs. The goal of this proposal is to develop an atomic force microscope (AFM) imaging-based assay that will allow a detailed study of the assembly of these nano-scale complexes. Using biotinylated HOP and streptavidin surfaces, Hsp90-HOP-Hsp70 assemblies will be studied and their formation monitored in situ and in real time. In addition, using the same AFM-based assay, the role of CHIP and the nature of its interaction with the Hsp90-HOP-Hsp70 assembly will be elucidated. Finally, this assay will be used to understand the effects of tighter binding TPRs and small molecules, which are capable of inhibiting Hsp90- HOP-Hsp70 formation. These novel studies will allow a new level of understanding of these nano-scale processes and assemblies. They have direct relevance to cancer, because inhibition of Hsp90 activity is a proven route to anti-cancer therapeutics.