Gene expression regulation by heat-shock proteins: the cardinal roles of HSF1 and Hsp90

Abstract

The ability to permit gene expression is managed by a set of relatively well known regulatory mechanisms. Nonetheless, such property can also be acquired during the life span as a consequence of environmental stimuli. Interestingly, some acquired information can be passed to the next generation of individuals without modifying gene information, but instead, the manner cells read and process such information. Molecular chaperones are classically related to the proper preservation of protein folding and anti-aggregation properties, but one of them, Hsp90, is a refined sensor of protein function facilitating the biological activity of properly folded client proteins that already have a preserved tertiary structure. Interestingly, Hsp90 can also function as a critical switch able to regulate biological responses due to its association to key client proteins such as histone deacetylases or DNA methylases. Thus, a growing amount of evidence has connected the action of Hsp90 to post-translational modifications of soluble nuclear factors, DNA, and histones, which epigenetically affects gene expression upon the onset of an unfriendly environment. Such response is commanded by the activation of the transcription factor HSF1. Even though a great number of stresses of diverse nature are known to trigger the stress response by activation of HSF1, it is still unanswered whether there are different types of molecular sensors for each type of stimulus. In this article, we will discuss various aspects of the regulatory action of HSF1 and Hsp90 on transcriptional regulation, and how this regulation may impact genetic assimilation mechanisms and the health of individuals.