Inhibits calcineurin-dependent transcriptional responses by binding to the catalytic domain of calcineurin A (PubMed:12809556). Could play a role during central nervous system development (By similarity). {ECO:0000250|UniProtKB:Q9JHG6, ECO:0000269|PubMed:12809556}. This is the function of RCAN1 (regulator of calcineurin 1, ENSG00000159200).