Heat shock proteins (HSP) are a class of functionally related proteins whose expression is increased when cells are exposed to elevated temperatures or other stress.This increase in expression istranscriptionally regulated. The dramatic upregulation of the heat shock proteins is a key part of the heat shock response and is induced primarily by heat shock factor (HSF).HSPs are found in virtually all living organisms, from bacteria to humans.
Heat-shock proteins are named according to their molecular weight. For example, Hsp60, Hsp70 and Hsp90 (the most widely-studied HSPs) refer to families of heat shock proteins on the order of 60, 70 and 90 kilodaltons in size, respectively. The small 8 kilodalton protein ubiquitin, which marks proteins for degradation, also has features of a heat shock protein
Discovery:
It is known that rapid heat hardening can be elicited by a brief exposure of cells to sub-lethal high temperature, which in turn provides protection from subsequent and more severe temperature. In 1962, Ritossa reported that heat and the metabolic inhibitor dinitrophenol induced a characteristic pattern of puffing in the chromosomes of Drosophila. This discovery eventually led to the identification of the heat-shock proteins (HSP) or stress proteins whose expression these puffs represented. Increased synthesis of selected proteins in Drosophila cells following stresses such as heat shock was first reported in 1974.
Beginning in the mid-1980s, investigators recognized that many HSPs function as molecular chaperones and thus play a critical role in protein folding, intracellular trafficking of proteins, and coping with proteins denatured by heat and other stresses. Accordingly, the study of stress proteins has undergone explosive growth.
for more detail you can see this link below.These are an open source files that are taken from other links
0 comments:
Post a Comment