To validate whether the proteins identified from cICAT were associated with mitochondria, we examined the GO cellular component annotation of the proteins identified from proteomics. Then, we performed a systematic data-integrative analysis to examine whether proteins identified from proteomics were matched with 13 reference mt protein datasets representing complementary independent studies of mt proteome, which include seven mt protein databases (HMPDb (http://bioinfo. nist.gov/hmpd/index.html), Maestro [52] , MitoProteome [53] , MitoRes [54] , Locate [55] , MitoP2, and SVM-trained MitoP2 [56] ) and six mt proteomics datasets (two MitoCarta datasets [57] , and four mtDNA depleted mitochondria proteomics datasets [33, 58, 59, 60] ). Some of the proteins from the database might contain mitochondrial proteins from other species, thus we only selected human mt proteins from these datasets to construct a reliable mt protein list. We validated 569 human proteins annotated as mitochondrial proteins and observed from at least one reference mitochondrial protein dataset.