Catalyzes calcium-induced ATP-independent rapid bidirectional and non-specific movement of the phospholipids (lipid scrambling or lipid flip-flop) between the inner and outer membrane of the mitochondria (By similarity). Plays an important role in mitochondrial respiratory function, morphology, and apoptotic response (By similarity). Mediates the translocation of cardiolipin from the mitochondrial inner membrane to outer membrane enhancing t-Bid induced cytochrome c release and apoptosis (Probable). Enhances TNFSF10-induced apoptosis by regulating the distribution of cardiolipin in the mitochondrial membrane resulting in increased release of apoptogenic factors and consequent amplification of the activity of caspases (By similarity). Regulates cardiolipin de novo biosynthesis and its resynthesis (By similarity). a cardiolipin(in) = a cardiolipin(out) a 1,2-diacyl-sn-glycero-3-phosphoethanolamine(in) = a 1,2-diacyl-sn-glycero-3-phosphoethanolamine(out) a 1,2-diacyl-sn-glycero-3-phosphocholine(in) = a 1,2-diacyl-sn-glycero-3-phosphocholine(out) a 1,2-diacyl-sn-glycero-3-phospho-L-serine(in) = a 1,2-diacyl-sn-glycero-3-phospho-L-serine(out) 1,2-diacyl-sn-glycero-3-phospho-(1'-sn-glycerol)(in) = 1,2-diacyl-sn-glycero-3-phospho-(1'-sn-glycerol)(out) Monomer (By similarity). Forms homooligomers upon binding to Ca(2+), Pb(2+) and Hg(2+) ions (By similarity). Interacts with PDCD6 in a calcium-dependent manner (By similarity). Interacts with PRKCD; interaction is enhanced by UV irradiation (PubMed:19428821). Palmitoylation regulates its localization to the cell membrane or the nucleus; trafficking to the cell membrane is dependent upon palmitoylation whereas in the absence of palmitoylation, localizes to the nucleus. The Proline-rich domain is required for phospholipid scramblase activity. Palmitoylation regulates its localization to the cell membrane or the nucleus; trafficking to the cell membrane is dependent upon palmitoylation whereas in the absence of palmitoylation, localizes to the nucleus. Belongs to the phospholipid scramblase family.