POU domain (IPR013847)

Short name: POU

Overlapping homologous superfamilies

Domain relationships



POU proteins are eukaryotic transcription factors containing a bipartite DNA binding domain referred to as the POU domain. The acronym POU (pronounced 'pow') is derived from the names of three mammalian transcription factors, the pituitary-specific Pit-1, the octamer-binding proteins Oct-1 and Oct-2, and the neural Unc-86 from Caenorhabditis elegans. POU domain genes have been described in organisms as divergent as C. elegans, Drosophila, Xenopus, zebrafish and human but have not been yet identified in plants and fungi. The various members of the POU family have a wide variety of functions, all of which are related to the development of an organism [PMID: 11159814].

The POU domain is a bipartite domain composed of two subunits separated by a non-conserved region of 15-55 aa. The N-terminal subunit is known as the POU-specific (POUs) domain (IPR000327), while the C-terminal subunit is a homeobox domain (IPR001356). 3D structures of complexes including both POU subdomains bound to DNA are available. Both subdomains contain the structural motif 'helix-turn-helix', which directly associates with the two components of bipartite DNA binding sites, and both are required for high affinity sequence-specific DNA-binding. The subdomains are connected by a flexible linker [PMID: 11183772, PMID: 8156594, PMID: 9009203]. In proteins a POU-specific domain is always accompanied by a homeodomain. Despite of the lack of sequence homology, 3D structure of POUs is similar to 3D structure of bacteriophage lambda repressor and other members of HTH_3 family [PMID: 11183772, PMID: 8156594].

This entry represents the complete POU domain.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0003677 DNA binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.