biostudies-literatureUnknown25(14)Samaddar MMitochondrial Hsp70 (mtHsp70) is essential for a vast repertoire of functions, including protein import, and requires effective interdomain communication for efficient partner-protein interactions. However, the in vivo functional significance of allosteric regulation in eukaryotes is poorly defined. Using integrated biochemical and yeast genetic approaches, we provide compelling evidence that a conserved substrate-binding domain (SBD) loop, L4,5, plays a critical role in allosteric communication governing mtHsp70 chaperone functions across species. In yeast, a temperature-sensitive L4,5 mutation (E467A) disrupts bidirectional domain communication, leading to compromised protein import and mitochondrial function. Loop L4,5 functions synergistically with the linker in modulating the allosterMolecular biology of the cell2129-42https://www.ebi.ac.uk/biostudies/studies/S-EPMC4091826biostudies-literatureRole of the loop L4,5 in allosteric regulation in mtHsp70s: in vivo significance of domain communication and its implications in protein translocation.PMC4091826D'Silva PGoswami AVPurushotham JSamaddar MHegde PfalseRole of the loop L4,5 in allosteric regulation in mtHsp70s: in vivo significance of domain communication and its implications in protein translocation.Mitochondrial Hsp70 (mtHsp70) is essential for a vast repertoire of functions, including protein import, and requires effective interdomain communication for efficient partner-protein interactions. However, the in vivo functional significance of allosteric regulation in eukaryotes is poorly defined. Using integrated biochemical and yeast genetic approaches, we provide compelling evidence that a conserved substrate-binding domain (SBD) loop, L4,5, plays a critical role in allosteric communication governing mtHsp70 chaperone functions across species. In yeast, a temperature-sensitive L4,5 mutation (E467A) disrupts bidirectional domain communication, leading to compromised protein import and mitochondrial function. Loop L4,5 functions synergistically with the linker in modulating the alloster2014-01-01T00:00:00Z2014 Jul2025-04-26T09:09:00.915Z2019-03-27T01:31:51ZS-EPMC40918262482937910.1091/mbc.E14-03-0821