BTB/POZ Domain

Domain Binding and Function

The BTB domain is a protein-protein interaction module consisting of approximately 120 amino acids that is found in over 600 different proteins in organisms ranging from yeast to humans. The domain was first identified as a conserved sequence element in the developmentally regulated Drosophila proteins Broad-complex, Tramtrack and Bric-abrac. The BTB domain, also known as the POZ (poxvirus and zinc finger) domain, is often found at the N-termini of several zinc finger transcription factors as well as Shaw-type potassium channels. Experimental studies have strongly implicated the BTB domain in the regulation of gene expression through the local control of chromatin conformation. In several cases, the BTB domain has been shown to mediate protein oligomerization which subsequently prevents high affinity DNA binding. Both homotypic and heterotypic protein-protein interactions have been observed because the BTB domain can form dimers as well as mediating interactions with non-BTB domain—containing proteins.

Structure Reference

1. Ahmad, K.F. et al. (1998) Proc. Natl. Acad. Sci. USA 95(21), 12123–12128.

Examples of Domain Proteins

Binding Examples

BTB Domain Proteins	Binding Partners
Zinc Finger Protein with Interaction Domain (ZID)	Homotypic interaction
Zinc Finger 5 Protein (ZF5)	Homotypic interaction
BCL-6 Zinc Finger Transcription Repressor	N-CoR corepressor, SMRT corepressor
GAG Zinc Finger Protein	Tramtrack (T+k) via BTB heterotypic interaction