Grainyhead Like Protein 3 (GRHL3)

SOM belongs to a family of transcription factors related to the Drosophila grainyhead (grh) protein. In Drosophila, grainyhead has a role in early dorsal/ventral patterning and in later organ and tissue development.

The longest variant, SOM1, encodes a deduced 607-amino acid protein containing an N-terminal activation domain, a central DNA-binding domain, and a C-terminal dimerization domain. It shares 90% amino acid identity with mouse Som, and more than 60% amino acid similarity with MGR and BOM. The SOM2 variant contains an alternate first coding exon compared with SOM1. The SOM3 variant lacks exon 2, which encodes a significant component of the transactivation domain.