HSP (Heat shock proteins) are a group of proteins induced by heat shock, the most prominent members of this group are a class of functionally related proteins involved in the folding and unfolding of other proteins. HSP expression is increased when cells are exposed to elevated temperatures or other stress. This increase in expression is transcriptionally 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 appear to serve a significant cardiovascular role. Hsp90, Hsp84, Hsp70, Hsp27, Hsp20 and alpha B crystallin all have been reported as having roles in the cardiovasculature.