Abstract:
The term molecular chaperone was first used to describe the ability of nucleoplasmin to prevent the aggregation of histones with DNA during the assembly of nucleosomes. Subsequently, the name was extended to proteins that mediate the post-translational assembly of oligomeric complexes protecting them from denaturation and/or aggregation. Hsp90 is a 90-kDa molecular chaperone that represents the major soluble protein of the cell. In contrast to most conventional chaperones, Hsp90 functions as a refined sensor of protein function and its principal role in the cell is to facilitate biological activity to properly folded client proteins that already have a preserved tertiary structure. Consequently, Hsp90 is related to basic cell functions such as cytoplasmic transport of soluble proteins, translocation of client proteins to organelles, and regulation of the biological activity of key signaling factors such as protein kinases, ubiquitin ligases, steroid receptors, cell cycle regulators, and transcription factors. A growing amount of evidence links the protective action of this molecular chaperone to mechanisms related to posttranslational modifications of soluble nuclear factors as well as histones. In this article, we discuss some aspects of the regulatory action of Hsp90 on transcriptional regulation and how this effect could have impacted genetic assimilation mechanism in some organisms.
摘要:
术语分子伴侣首先用于描述核纤溶酶在核小体组装过程中防止组蛋白与DNA聚集的能力。随后,该名称扩展到介导寡聚复合物翻译后组装的蛋白质,保护它们免受变性和/或聚集。Hsp90是90kDa分子伴侣,其代表细胞的主要可溶性蛋白。与大多数传统伴侣相比,Hsp90用作蛋白质功能的精制传感器,其在细胞中的主要作用是促进生物活性,以适当折叠已经具有保留的三级结构的客户蛋白。因此,Hsp90与基本细胞功能有关,例如可溶性蛋白质的细胞质运输,将客户蛋白转运到细胞器,和调节关键信号因子如蛋白激酶的生物活性,泛素连接酶,类固醇受体,细胞周期调节剂,和转录因子。越来越多的证据将这种分子伴侣的保护作用与可溶性核因子以及组蛋白的翻译后修饰相关的机制联系起来。在这篇文章中,我们讨论了Hsp90对转录调控的调节作用的某些方面,以及这种作用如何影响某些生物的遗传同化机制。