Calcineurin Subunit B Type 1 belongs to the calcineurin regulatory subunit family. Calcineurin Subunit B Type 1 is a Ser/Thr-specific calcium and calmodulin-dependent protein phosphatase. It is composed of a catalytic subunit (A) and a regulatory subunit (B). It contains four EF-hand domains and four functional calcium-binding sites. Calcineurin Subunit B Type 1 plays an improtant role in the T cell activation pathway.