PMCA belongs to a family of P-type primary ion transport ATPases, and is expressed in a variety of tissues, including the brain. In mammals three genes encode three SERCA pumps. Each transcript undergoes tissue-dependent alternative splicing. SERCA1a and 1b are expressed in adult and neonatal skeletal muscle respectively. SERCA2a is also expressed in skeletal muscle, while SERCA2b is ubiquitously expressed. SERCA3 is expressed in a limited number of non-muscle cells. Although all SERCAs are regulated, SERCA2b undergoes extensive regulation at the protein level, such as protein-protein interaction, phosphorylation and glycosylation.