HSPE1
Description
The HSPE1 (heat shock protein family E (Hsp10) member 1) is a protein-coding gene located on chromosome 2.
HSPE1, also known as Hsp10, is a protein encoded by the HSPE1 gene in humans. It is a mitochondrial chaperonin, similar to the bacterial GroES, and works in conjunction with Hsp60 (also known as GroEL in bacteria). Hsp10 forms a ring-shaped oligomer composed of 6 to 8 identical subunits, while Hsp60 forms a double-ring structure with each ring containing 7 identical subunits. These rings assemble in the presence of Mg2+-ATP. Hsp60 provides an isolated environment for protein folding, and Hsp10 binds to Hsp60, regulating the release of the folded protein in an Mg2+-ATP-dependent manner. The binding of Hsp10 to Hsp60 inhibits the ATPase activity of Hsp60. Hsp10 also binds ATP cooperatively, with an affinity similar to Hsp60. Each Hsp60 subunit has three distinct domains: apical, intermediate, and equatorial. The apical domain contains binding sites for both Hsp10 and unfolded protein substrates. The equatorial domain contains the ATP-binding site and most of the oligomeric contacts. The intermediate domain links the apical and equatorial domains and transmits allosteric information between them.
HSPE1, also known as Hsp10, is a co-chaperonin involved in mitochondrial protein import and macromolecular assembly. It collaborates with Hsp60 to ensure the proper folding of imported proteins. HSPE1 can also prevent protein misfolding and aid in the refolding and assembly of unfolded polypeptides generated under stress conditions within the mitochondrial matrix. The functional units of these chaperonins consist of heptameric rings of the large subunit Hsp60, forming a back-to-back double ring structure. In a cyclic process, Hsp60 rings bind one unfolded substrate protein per ring, followed by ATP binding and association with two heptameric rings of the co-chaperonin HSPE1. This sequestration of the substrate protein within the inner cavity of Hsp60 allows for undisturbed folding for a specific duration. Simultaneous hydrolysis of ATP in all Hsp60 subunits leads to the dissociation of the chaperonin rings, releasing ADP and the correctly folded substrate protein.
HSPE1 is also known as CPN10, EPF, GROES, HSP10.
