HSP 90 Assoc. with Steroid Receptors & Other Proteins

描述（由申请人提供）：hsp90是细胞中的关键分子伴侣蛋白。它参与产生和维持许多重要调节蛋白的活性状态，包括许多转录因子和蛋白激酶。类固醇受体的活性依赖于热休克蛋白90的陪伴，我们已经使用孕激素受体（PR）作为模型客户端蛋白的热休克蛋白90的作用机制的研究。提出的研究的目的是定义的属性和机制的热休克蛋白90客户端蛋白结合，并获得信息的后果，这一重要的相互作用。提出了三个具体目标。在目标1中，将开发用于直接描述热休克蛋白90与PR结合的方法。这种相互作用是复杂的，通常需要额外的辅助分子伴侣。然而，通过温和的加热，可以诱导热休克蛋白90结合PR，而无需其他蛋白质的帮助，从而可以在简化的系统中研究客户端结合的几个方面。在目标2中，将研究hsp90与小肽的结合，作为理解hsp90的客户端结合活性的第二种方法。使用噬菌体展示方法从随机文库中选择肽，并表征其在hsp90上的结合位点。在目标3中，这些关于hsp90的新信息将用于研究在更复杂的系统中客户端结合的作用和调节，其中hsp90与其他伴侣和辅助伴侣合作以产生客户端蛋白的活性形式。目前，热休克蛋白90选择和结合客户蛋白的机制尚不清楚。这些研究应该提供有价值的新的见解，这是关键的理解热休克蛋白90的生物学意义的机制。

DESCRIPTION (provided by applicant): hsp90 is a key molecular chaperone protein in the cell. It participates in producing and maintaining the active states of many important regulatory proteins including a number of transcription factors and protein kinases. The activities of steroid receptors are dependent on hsp90 chaperoning and we have used the progesterone receptor (PR) as a model client protein for studies on the mechanism of hsp90 action. The objective of the studies proposed is to define the properties and the mechanism of hsp90 binding to client proteins and to gain information on the consequences of this important interaction. Three specific aims are proposed. In Aim 1, methods will be developed to use in describing directly the binding of hsp90 to PR. This interaction is complex and normally requires additional co-chaperones. However, by mild heating one can induce hsp90 to bind PR without assistance by other proteins allowing the study of several aspects of client binding in a simplified system. In Aim 2, the binding of hsp90 to small peptides will be studied as a second approach to understanding the client binding activity of hsp90. Peptides will be selected from random libraries using phage display methods and their binding sites on hsp90 will be characterized. In Aim 3, this new information on hsp90 will be used to study the roles and the regulation of client binding in the more complex system where hsp90 cooperates with other chaperones and co-chaperones to produce active forms of client proteins. At present, the mechanism by which hsp90 selects and binds client proteins is unknown. These studies should provide valuable new insights into this mechanism which is key to understanding the biological significance of hsp90.