ATPase, Ca++ Transporting, Type 2C, Member 2 (ATP2C2)

SPCA2 has an invariant gln residue in transmembrane domain 6 that is critical for Mn(2+) selectivity, but it has a divergent Ca(2+)-binding EF-hand-like motif at its N terminus, suggesting weak Ca(2+) binding. SPCA2 shares 64% amino acid identity with SPCA1 (ATP2C1), with highest divergence at the N- and C-terminal ends. Transmembrane domains 4, 5, and 6, which bind and transport ions in other SPCA proteins, are nearly identical in SPCA1 and SPCA2.

SPCA2 at an apparent molecular mass of about 105 kD, with highest expression in brain and testis, and much weaker expression in lung, kidney, and spleen. Immunohistochemical analysis of rat hippocampal neurons showed punctate staining of cell bodies and dendrites and strong perinuclear staining, suggesting that SPCA2 localizes to vesicles derived from the trans-Golgi network.