InterPro domain: IPR013126

Heat shock proteins, Hsp70 chaperones help to fold many proteins. Hsp70 assisted folding involves repeated cycles of substrate binding and release. Hsp70 activity is ATP dependent. Hsp70 proteins are made up of two regions: the amino terminus is the ATPase domain and the carboxyl terminus is the substrate binding region [ 1 ].

Hsp70 proteins have an average molecular weight of 70kDa [ 2 , 3 , 4 ]. In most species, there are many proteins that belong to the Hsp70 family. Some of these are only expressed under stress conditions (strictly inducible), while some are present in cells under normal growth conditions and are not heat-inducible (constitutive or cognate) [ 5 , 6 ]. Hsp70 proteins can be found in different cellular compartments (nuclear, cytosolic, mitochondrial, endoplasmic reticulum, for example).

This entry represents the Hsp70 family, and includes chaperone protein DnaK and luminal-binding proteins. It also includes heat shock protein 110 (Hsp110) from Caenorhabditis elegans which helps prevent the aggregation of denatured proteins in neurons [ 7 ]. Also included is endoplasmic reticulum (ER) chaperone BiP (HSPA5) which is important for protein folding and quality control in the ER [ 8 ].

1. The Hsp70 and Hsp60 chaperone machines. Cell 92, 351-66
2. Essential roles of 70kDa heat inducible proteins. Bioessays 11, 48-52
3. Speculations on the functions of the major heat shock and glucose-regulated proteins. Cell 46, 959-61
4. Heat-shock proteins. Coming in from the cold. Nature 332, 776-7
5. Three-dimensional structure of the ATPase fragment of a 70K heat-shock cognate protein. Nature 346, 623-8
6. The Caenorhabditis elegans hsp70 gene family: a molecular genetic characterization. Gene 64, 241-55
7. An ALS-linked mutant SOD1 produces a locomotor defect associated with aggregation and synaptic dysfunction when expressed in neurons of Caenorhabditis elegans. PLoS Genet. 5, e1000350
8. Close and Allosteric Opening of the Polypeptide-Binding Site in a Human Hsp70 Chaperone BiP. Structure 23, 2191-2203