The NPAT gene encodes a protein required for the G1/S transition of the mitotic cell cycle. This protein acts as a cyclin E-CDK2 phosphorylation substrate and its effects on cell-cycle progression are enhanced by the co-expression of cyclin E and CDK2. NPAT can function as a transcription coactivator as well as a corepressor, and is responsible for activating the transcription of the histone H2A, histone H2B, histone H3 and histone H4 genes. It is required for regulating the promoters of the ATM, MIZF and PRKDC genes. It is believed that NPAT carries out its transcriptional activity in part by recruiting the NuA4 histone acetyltransferase (HAT) complex to target gene promoters.

The NPAT gene is located on the long arm of chromosome 11. It spans a length of 65.4 kb of DNA and its coding sequence is spread across 20 exons. The gene encodes a 154 kDa protein product composed of 1427 amino acids. While NPAT is ubiquitously expressed in the human body, overexpression is seen in the lung, pancreas and peripheral blood mononuclear cells.