Plasma membrane calcium-transporting ATPase 1 (ATP2B1, also known as PMCA1) belongs to the IIB subfamily of P-type ATPases, whose members are plasma membrane Ca2+ ATPases (PMCAs) that catalyse the hydrolysis of ATP coupled with the transport of calcium []. ATP2B1 is widely expressed in animal tissues during development []. Its auto-inhibitory C-terminal tail can be cleaved by a protease-calpain []. This activation by calpain may have a role in the activation of erythrocytes []. In breast cancer cells, ATP2B1 regulates cell death pathways in the presence of cell death stimuli []. It may also represent one of the sites of action of maitotoxin (MTX), one of the most potent toxins produced by the "red-tide"dinoflagellate Gambierdiscus toxicus. MTX-induced currents are significantly reduced by knockdown of ATP2B1, and the toxin may bind to and convert the PMCA pump into a Ca(2+)-permeable nonselective cation channel [].
