Catalytic component of P4-ATPase flippase complex, which catalyzes the hydrolysis of ATP coupled to the transport of phosphatidylcholine (PC) from the outer to the inner leaflet of the plasma membrane. May contribute to the maintenance of membrane lipid asymmetry. ATP + H2O + phospholipidSide 1 = ADP + phosphate + phospholipidSide 2. a 1,2-diacyl-sn-glycero-3-phosphocholine(out) + ATP + H2O = a 1,2-diacyl-sn-glycero-3-phosphocholine(in) + ADP + H(+) + phosphate Component of a P4-ATPase flippase complex which consists of a catalytic alpha subunit ATP8B2 and an accessory beta subunit TMEM30A or TMEM30B. Efficient exit from the endoplasmic reticulum requires the presence of TMEM30A or TMEM30B. Isoform 3 is ubiquitous, with highest expression in aorta, cerebellum and uterus. Belongs to the cation transport ATPase (P-type) (TC 3.A.3) family. Type IV subfamily.