The P-type adenosinetriphosphatases (P-type ATPases) are a family of proteins which use the free energy of ATP hydrolysis to drive uphill transport of ions across membranes. Several subfamilies of P-type ATPases have been identified. One subfamily catalyzes transport of heavy metal ions. Another subfamily transports non-heavy metal ions (NMHI). The protein encoded by this gene is a member of the third subfamily of P-type ATPases and acts to transport amphipaths, such as phosphatidylserine. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008].