Background：

May mediate accelerated ATP-independent bidirectional transbilayer migration of phospholipids upon binding calcium ions that results in a loss of phospholipid asymmetry in the plasma membrane. May play a central role in the initiation of fibrin clot formation， in the activation of mast cells and in the recognition of apoptotic and injured cells by the reticuloendothelial system. Seems to play a role in apoptosis， through translocation of cardiolipin from the inner to the outer mitochondrial membrane which promotes BID recruitment and enhances tBid-induced mitochondrial damages.