Phospholipid-transporting ATPase IG (also known as ATP11C) belongs to subfamily IV of the P-type ATPases (P4-ATPase) family, whose members transport phospholipids across the membrane. ATP11C is ubiquitously expressed and binds CDC50A as its beta-subunit []. In mice, ATP11C plays an important role in the proper development of B-cell lymphocytes [, , ]. In human cells, ATP11C can function as a phosphatidylserine (PtdSer) flippase at the plasma membrane. During apoptosis, the inactivation of ATP11C is required for cells to expose and display apoptotic PtdSer, which then serves as an "eat me"signal for macrophages to engulf the cells [].
Cell cycle control protein 50A (CDC50A, also known as TMEM30A) is an accessory component of the phospholipid-transporting ATPase (P4-ATPase) complex which catalyses the hydrolysis of ATP coupled to the transport of phospholipids across the membrane []. It can interact with several P4-ATPases, such as ATP8A1, ATP8A2, ATP8B1, ATP8B2, ATP11A, ATP11B and ATP11C [, , ]. CDC50A is a terminal-glycosylated glycoprotein and is expressed in hepatocytes and liver sinusoidal endothelial cells. In pancreas and stomach, it localises to secretory vesicles, while in kidney, it localises to the apical region of proximal convoluted tubules of the cortex []. In human carcinoma cells, CDC50A plays a key role in the uptake of the anticancer drug perifosine [].
