Inhibits calcineurin-dependent transcriptional responses by binding to the catalytic domain of calcineurin A. Could play a role during central nervous system development (PubMed:11231093). Interacts with RAF1 and PPP3R1 (By similarity). Interacts with PPP3CA (PubMed:12809556). Additional isoforms seem to exist. Highly expressed in heart and skeletal muscle. Also expressed in all other tissues. Phosphorylation increases its ability to inhibit calcineurin and decreases protein half-life. Belongs to the RCAN family. Truncated N-terminus.