The yeast mitochondrial GrpE homologue, Mge1, assists matrix Hsp70 in both protein translocation across the mitochondrial membranes and subsequent protein folding. We expressed mtHsp70 and Mge1 in Escherichia coli and analyzed their function in the ATP hydrolysis cycle. Mge1 stimulates ATP hydrolysis by mtHsp70 about twofold. Addition of inorganic phosphate inhibits ATP hydrolysis by preventing ADP release from mtHsp70. Mge1 has no direct effect on gamma-phosphate release from mtHsp70, yet indirectly relieves the phosphate inhibition by stimulating ADP release. We conclude that Mge1 promotes the ATPase cycle of mtHsp70 by increasing the rate of ADP release. ATP then rapidly binds to mtHsp70 such that the total amount of mtHsp70-bound nucleotide is not changed by Mge1.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|