FLAG-immunoprecipitation was performed in mitochondrial extracts from MITRAC15FLAG-expressing cells after siRNA-mediated down regulation of ACAD9 and pulse radiolabeling. SDS-PAGE followed by autoradiography was used to analyze eluates. Relative signal intensity of ND2, ND3 and ND4L were normalized to ATP6 (total) or isolation efficiency (eluate). Total 2 %, Eluate 100 %. Error bars indicate SEM from three biological replicates; **p < 0.01; unpaired t-test. 