Calcineurin (CN)

Calcineurin is a highly conserved, calcium (Ca²⁺)- and calmodulin-dependent serine/threonine protein phosphatase that plays a central role in cellular signal transduction, especially in immune function and cardiovascular physiology. It is a heterodimer composed of a catalytic subunit (Calcineurin A) and a regulatory subunit (Calcineurin B). Calcineurin dephosphorylates specific substrates in response to increased intracellular Ca²⁺ levels, with a key function being the activation of T cells via NFAT dephosphorylation. It is a target for immunosuppressant drugs like cyclosporin A and tacrolimus, used to prevent organ transplant rejection and treat autoimmune diseases. Dysregulation of calcineurin is implicated in neurodegenerative and cardiovascular diseases.

Other names

Protein Phosphatase 3PP3CaN

Calcineurin inhibitors (cyclosporin A and tacrolimus) bind to cyclophilin or FKBP12, respectively, and the resulting complex inhibits calcineurin activity.