Loading AI tools
From Wikipedia, the free encyclopedia
The BTB/POZ domain (BTB for BR-C, ttk and bab[2] or POZ for Pox virus and Zinc finger[3]) is a structural domain found in proteins across the domain Eukarya.[4] Given its prevalence in eukaryotes and its absence in Archaea and bacteria, it likely arose after the origin of eukaryotes.[5] While primarily a protein-protein interaction domain,[5] some BTB domains have additional functionality in transcriptional regulation,[6] cytoskeletal mobility,[7] protein ubiquitination and degradation,[8][9][10] and ion channel formation and operation.[11] BTB domains have traditionally been classified by the other structural features present in the protein.[4]
The BTB/POZ domain was first described by two independent research groups in 1994. Researchers at UCLA found a conserved 115 amino acid motif in nine Drosophila proteins, including Broad complex, tramtrack, and bric-a-brac, and labelled the conserved region the BTB domain.[2] At the same time, a group at Imperial Cancer Research Fund Laboratories in London discovered the same 120 amino acid motif in a set of otherwise unrelated zinc finger proteins and a set of pox-virus proteins, and thus named the region the POZ domain.[3]
The motif is approximately 120 amino acids long, with a core fold of 95 amino acids that form five alpha helices and three beta sheets.[4] The alpha helices form two hairpin structures, A1/A2 and A4/A5, out of the first and second and the fourth and fifth alpha helices respectively. The remaining alpha helix, A3, bridges the two. The three beta sheets cap the A1/A2 hairpin.[4] Additional secondary structures can surround this core fold. For example, BTB domains in Kelch proteins, C2H2 zinc finger proteins, and HTH-containing proteins frequently include an additional alpha helix and beta sheet at the N-terminus of the domain.[12]
The BTB domain is primarily a protein-protein interaction domain. In zinc-finger proteins, it commonly forms homodimers with other BTB domains, mediates heteromeric dimerization, and recruits transcriptional corepressors.[5]
Seamless Wikipedia browsing. On steroids.
Every time you click a link to Wikipedia, Wiktionary or Wikiquote in your browser's search results, it will show the modern Wikiwand interface.
Wikiwand extension is a five stars, simple, with minimum permission required to keep your browsing private, safe and transparent.
