Paired box protein Pax-4 (PAX4)

Plays an essential role in the differentiation and development of pancreatic islet beta cells. Transcriptional repressor that binds to a frequent element in the glucagon, insulin and somatostatin promoters.

Competes with PAX6 with this same promoter binding site. Isoform 2 seems to be a dominant negative form antagonizing PAX4 transcriptional activity.