CC2D1A is a transcriptional repressor that binds to a conserved 14-bp 5'-repressor element and regulates expression of the 5-hydroxytryptamine (serotonin) receptor 1A gene in neuronal cells. The DNA binding and transcriptional repressor activities of the protein are inhibited by calcium. A mutation in this gene results in nonsyndromic mental retardation-3.Synonyms: Coiled-coil and C2 domain-containing protein 1A, FRE under dual repression-binding protein, Five repressor element under dual repression-binding protein 1, Freud-1, Putative NF-kappa-B-activating protein 023N