Molecular chaperones: towards a characterization of the heat-shock protein 70 family.

The characterization of molecular chaperones is of central importance for an understanding of cellular protein-folding reactions. Numerous biochemical and genetic studies have now been complemented by the high-resolution structures of Hsp70 and GroEL, representatives of the two major classes of chaperone proteins, and the availability of a complete eukaryotic genome, revealing the presence of 14 distinct genes for Hsp70s in the yeast Saccharomyces cerevisiae. Here, the authors focus on recent progress in understanding the interactions of Hsp70s with their substrates and the enzymology of their regulation.