bioimagesUnknownhttps://www.ebi.ac.uk/biostudies/studies/S-BIAD1515bioimagesSpecimenImage analysisAnnotationsFundingStudy ComponentorganisationBiosampleImage correlationAssociationsImage acquisitionChris BroseyJohn TainerfalseNADH-bound AIF activates the mitochondrial CHCHD4/MIA40 chaperone by a substrate-mimicry mechanismMitochondrial metabolism requires chaperoned import of disulfide-stabilized proteins via CHCHD4/MIA40 and its enigmatic interaction with oxidoreductase Apoptosis-Inducing Factor (AIF). By crystallizing human CHCHD4’s AIF-interaction domain with an activated AIF dimer, we uncover how NADH allosterically configures AIF to anchor CHCHD4’s β-hairpin and histidine helix motifs to the inner mitochondrial membrane. The structure further reveals similarity between the AIF-interaction domain and recognition sequences of CHCHD4 substrates. NMR and X-ray scattering (SAXS) solution measurements, mutational analyses, and biochemistry show that the substrate-mimicking AIF-interaction domain shields CHCHD4’s redox-sensitive active site. Disrupting this shield critically activates CHCHD4 substrate affini2024-12-31T00:00:00Z2024-12-31T18:26:26.016Z2024-12-11T00:46:57.483ZS-BIAD1515