BTB

Broad-Complex, Tramtrack and Bric a brac
BTB
SMART accession number:SM00225
Description: Domain in Broad-Complex, Tramtrack and Bric a brac. Also known as POZ (poxvirus and zinc finger) domain. Known to be a protein-protein interaction motif found at the N-termini of several C2H2-type transcription factors as well as Shaw-type potassium channels. Known structure reveals a tightly intertwined dimer formed via interactions between N-terminal strand and helix structures. However in a subset of BTB/POZ domains, these two secondary structures appear to be missing. Be aware SMART predicts BTB/POZ domains without the beta1- and alpha1-secondary structures.
Interpro abstract (IPR000210): The BTB (for BR-C, ttk and bab) [(PUBMED:7938017)] or POZ (for Pox virus and Zinc finger) [(PUBMED:7958847)] domain is present near the N terminus of a fraction of zinc finger (IPR007087) proteins and in proteins that contain the IPR006652 motif such as Kelch and a family of pox virus proteins. The BTB/POZ domain mediates homomeric dimerisation and in some instances heteromeric dimerisation [(PUBMED:7958847)]. The structure of the dimerised PLZF BTB/POZ domain has been solved and consists of a tightly intertwined homodimer. The central scaffolding of the protein is made up of a cluster of alpha-helices flanked by short beta-sheets at both the top and bottom of the molecule [(PUBMED:9770450)]. POZ domains from several zinc finger proteins have been shown to mediate transcriptional repression and to interact with components of histone deacetylase co-repressor complexes including N-CoR and SMRT [(PUBMED:9019154), (PUBMED:9824158), (PUBMED:9765306)]. The POZ or BTB domain is also known as BR-C/Ttk or ZiN.
GO function:protein binding (GO:0005515)
Family alignment:
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There are 31937 BTB domains in 30174 proteins in SMART's nrdb database.

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