Mitochondrial flashes (mitoflashes) represent multifaceted signaling events of single mitochondrion, including transient burst of superoxide, depolarization of mitochondrial membrane potential (△Ψm) and depletion of the ETC electron donors NADH and FADH2.Since mitochondrial Ca2+ plays important modulatory roles on mitoflash activity, we screened the regulatory proteins with EF-hand or C2 domains included in MitoCarta library.NDUFAB1, an acetyl carrier like domain containing accessory subunit of mitochondrial complex I, forms one important regulator of mitoflashes in HeLa cells and cardiomyocytes.