Catalytic component of a P4-ATPase flippase complex which catalyzes the hydrolysis of ATP coupled to the transport of aminophospholipids, phosphatidylserines (PS) and phosphatidylethanolamines (PE), from the outer to the inner leaflet of intracellular membranes (PubMed:30018401). May contribute to the maintenance of membrane lipid asymmetry in endosome compartment (PubMed:30018401).
