Nanoscale mechanisms of Hsp90 and its co-chaperones

描述（由申请人提供）：许多癌症是由正常蛋白质的突变形式的异常活性引起的，其严重依赖于“分子伴侣”HSP 90进行折叠。Hsp 90不是单独作用的，而是与Hsp 90、Hsp 70、HOP和CHIP等蛋白在多蛋白组装体中联合作用。这些关联由称为TPR的基序介导。该提案的目标是开发一种基于原子力显微镜（AFM）成像的测定方法，该方法将允许对这些纳米级复合物的组装进行详细研究。使用生物素化的HOP和链霉亲和素表面，将研究Hsp 90-HOP-Hsp 70组装体，并原位和真实的时间监测它们的形成。此外，使用相同的基于AFM的测定，CHIP的作用及其与Hsp 90-HOP-Hsp 70组装体相互作用的性质将被阐明。最后，该测定将用于了解更紧密结合的TPR和小分子的作用，其能够抑制Hsp 90-HOP-Hsp 70形成。这些新的研究将使人们对这些纳米尺度的过程和组装有一个新的认识。它们与癌症直接相关，因为抑制Hsp 90活性是抗癌治疗的一种已被证明的途径。

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.