HSP10/EPF Protein, Human (His)

The HSP10/EPF protein functions as a co-chaperonin actively involved in mitochondrial protein import and macromolecular assembly. Collaborating with Hsp60, it facilitates the correct folding of imported proteins and, under stress conditions in the mitochondrial matrix, may prevent misfolding while promoting the refolding and proper assembly of unfolded polypeptides. The operational units of these chaperonins comprise heptameric rings of the large subunit Hsp60, forming a back-to-back double ring structure. In a cyclic process, Hsp60 ring complexes bind unfolded substrate proteins, followed by ATP binding and association with two heptameric rings of the co-chaperonin Hsp10. This leads to the sequestration of the substrate protein within the inner cavity of Hsp60, allowing for undisturbed folding. Synchronous ATP hydrolysis in all Hsp60 subunits results in the dissociation of the chaperonin rings, releasing ADP and the folded substrate protein. The HSP10/EPF protein forms a homoheptamer arranged in a ring structure and interacts with a Hsp60 tetradecamer to create the symmetrical football complex. These molecular interactions underscore the essential role of HSP10/EPF in orchestrating the folding and assembly of mitochondrial proteins.