Transports phosphatidylserine from the outer to the inner leaflet of the plasma membrane, thereby maintaining the enrichment of this phospholipid in the inner leaflet (PubMed:18436785, PubMed:21170358, PubMed:23427264). Ectopic exposure of phosphatidylserine on the cell surface may result in removal of living cells by neighboring phagocytes (PubMed:18436785). Regulation of the phosphatidylserine distribution in plasma membranes is likely to help in the maintenance and control of the membrane surface charge (PubMed:23427264). Plays a role in the formation of the tubular membrane structure and in membrane trafficking and is specifically involved in the recycling and degradation of endocytic cargo, likely with its chaperone protein chat-1 (PubMed:21170358, PubMed:23427264). ATP + H2O + phospholipidSide 1 = ADP + phosphate + phospholipidSide 2. a 1,2-diacyl-sn-glycero-3-phospho-L-serine(out) + ATP + H2O = a 1,2-diacyl-sn-glycero-3-phospho-L-serine(in) + ADP + H(+) + phosphate Colocalizes with its chaperone chat-1 at apical and basolateral cell membranes, on early endosomes and on recycling endosomes. Also localizes to intracellular tubular and vesicular structures. Results in abnormal formation of intestinal vacuoles. Belongs to the cation transport ATPase (P-type) (TC 3.A.3) family. Type IV subfamily.