The product of this gene is a component of the nuclear factor of activated T cells DNA-binding transcription complex. The protein complex consists of NFAT1, NFAT2 (NFATc1 or NFATc), NFAT3, and NFAT4. All members of this family are transcription factors with a Rel homology domain and regulate gene transcription in concert with AP-1 (Jun/Fos) to orchestrate an effective immune response. NFAT proteins are predominantly expressed in cells of the immune system but are also expressed in skeletal muscle, keratinocytes and adipocytes, regulating cell differentiation programs in these cells. In resting cells, NFAT proteins are heavily phosphorylated and localized in the cytoplasm. Increased intracellular calcium concentrations activate the calcium/calmodulin-dependent serine phosphatase calcineurin, which dephosphorylates NFAT proteins, resulting in their subsequent translocation to the nucleus.
Proteins belonging to this family of transcription factors play a central role in inducible gene transcription during immune response. The product of this gene is an inducible nuclear component. It functions as a major molecular target for the immunosuppressive drugs such as cyclosporin A. Five transcript variants encoding distinct isoforms have been identified for this gene. Different isoforms of this protein may regulate inducible expression of different cytokine genes.