PARTNER PROTEINS DETERMINE MULTIPLE FUNCTIONS OF HSP70

The 70 kDa heat shock proteins (Hsp70s) are ubiquitous molecular chape rones that are best known for their participation in protein folding. However, evidence is accumulating that Hsp70s perform several other ce llular functions in cooperation with specific soluble or membrane-boun d partner proteins. While the basic function of Hsp70s is explained by their ability to bind unfolded polypeptide segments, the partner prot eins appear to customize them for specific roles such as involvement i n protein traffic and folding, translocation of preproteins across mem branes, and gene regulation.