Catalytic component of a P4-ATPase flippase complex which catalyzes the hydrolysis of ATP coupled to the transport of aminophospholipids from the outer to the inner leaflet of various membranes and ensures the maintenance of asymmetric distribution of phospholipids (PubMed:19778899, PubMed:24706822, PubMed:31371510, PubMed:26592152). Phospholipid translocation seems also to be implicated in vesicle formation and in uptake of lipid signaling molecules. Reconstituted to liposomes, the ATP8A2:TMEM30A flippase complex predominantly transports phosphatidylserine (PS) and to a lesser extent phosphatidylethanolamine (PE) (PubMed:19778899, PubMed:24706822, PubMed:31371510, PubMed:26592152). Phospholipid translocation is not associated with a countertransport of an inorganic ion or other charged substrate from the cytoplasmic side toward the exoplasm in connection with the phosphorylation from ATP (PubMed:31371510). ATP8A2:TMEM30A may be involved in regulation of neurite outgrowth. Proposed to function in the generation and maintenance of phospholipid asymmetry in photoreceptor disk membranes and neuronal axon membranes. May be involved in vesicle trafficking in neuronal cells. Required for normal visual and auditory function; involved in photoreceptor and inner ear spiral ganglion cell survival. 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 a 1,2-diacyl-sn-glycero-3-phosphoethanolamine(in) + ATP + H2O = a 1,2-diacyl-sn-glycero-3-phosphoethanolamine(out) + ADP + H(+) + phosphate ATPase activity is stimulated by phosphatidylserine (PS) and minimally by phosphatidylethanolamine (PE). ATPase activity is inhibited by N-ethylmaleimide (NEM) and vanadate. Flippase activity is inhibited by NEM and 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS). Component of a P4-ATPase flippase complex which consists of a catalytic alpha subunit and an accessory beta subunit (PubMed:21454556, PubMed:26592152). Interacts with TMEM30A to form a flippase complex (PubMed:21454556). Localizes to the Golgi and endosomes in photoreceptor cells (By similarity). Localizes to disk membranes of rod photoreceptor outer segments (ROS) (PubMed:21454556). Expressed in retinal photoreceptor cells and testis. Belongs to the cation transport ATPase (P-type) (TC 3.A.3) family. Type IV subfamily. Extended N-terminus.