Transcription factor involved, among others, in the transcriptional regulation of osmoprotective and inflammatory genes. Mediates the transcriptional response to hypertonicity (PubMed:10051678). Positively regulates the transcription of LCN2 and S100A4 genes; optimal transactivation of these genes requires the presence of DDX5/DDX17 (PubMed:22266867). Binds the DNA consensus sequence 5'-[ACT][AG]TGGAAA[CAT]A[TA][ATC][CA][ATG][GT][GAC][CG][CT]-3' (PubMed:10377394). Homodimer when bound to DNA, completely encircles its DNA target. Interacts with CIDEC; this interaction is direct and retains NFAT5 in the cytoplasm (By similarity). Does not bind with Fos and Jun transcription factors. Interacts with DDX5 and DDX17; this interaction leads to DDX5/DDX17 recruitment to LNC2 and S100A4 promoters and NFAT5-mediated DDX5/DDX17-enhanced transactivation (PubMed:22266867). Nuclear distribution increases under hypertonic conditions. Widely expressed, with highest levels in skeletal muscle, brain, heart and peripheral blood leukocytes. Phosphorylated (PubMed:10377394). Phosphorylated at Thr-135 by CDK5 in response to osmotic stress; this phosphorylation mediates its rapid nuclear localization (PubMed:21209322). The transcript encoding this isoform contains an alternative coding exon 4 which contains 2 stop codons and could target the transcript to nonsense-mediated mRNA decay after the pioneer round of translation, as suggested by the decreased NFAT5 protein levels when the number of exon 4-containing transcripts increases. The insertion of exon 4 is stimulated in the presence of DDX5 and DDX17. Isoform A sequence described in this entry starts at the first methionine downstream of exon 4 last stop codon. An alternative protein sequence can be predicted from this transcript starting at Met-1. This isoform encodes an 81 amino acid-long protein. The transcript encoding this isoform contains an alternative coding exon 4 which contains 2 stop codons and could target the transcript to nonsense-mediated mRNA decay after the pioneer round of translation, as suggested by the decreased NFAT5 protein levels when the number of exon 4-containing transcripts increases. The insertion of exon 4 is stimulated in the presence of DDX5 and DDX17. Extended N-terminus.