Functionally, ectopic expression of wild‐type (WT) COX4I1 cDNA, but not the P1‐deleted (ΔP1) or P2‐deleted (ΔP2) variants, rescued impaired cellular survival (Figure 5C) and mitochondrial respiration (Figure 5D) in COX4I1 knockout leukemia cells. Here, COX4I1 is linked to leukemia.