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]

BTB/POZ domain
Structure of the BTB domain from PLZF.[1]
Identifiers
SymbolBTB
PfamPF00651
InterProIPR013069
PROSITEPS50097
SCOP21buo / SCOPe / SUPFAM
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
PDB1buo​ , 1cs3​ , 1r28​ , 1r29​ , 1r2b​ , 2nn2​ , 3bim

Discovery

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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]

Structure

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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]

Function

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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]

References

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  1. ^ Ahmad KF, Engel CK, Privé GG (October 1998). "Crystal structure of the BTB domain from PLZF". Proceedings of the National Academy of Sciences of the United States of America. 95 (21): 12123–12128. Bibcode:1998PNAS...9512123F. doi:10.1073/pnas.95.21.12123. PMC 22795. PMID 9770450.
  2. ^ a b Zollman S, Godt D, Privé GG, Couderc JL, Laski FA (October 1994). "The BTB domain, found primarily in zinc finger proteins, defines an evolutionarily conserved family that includes several developmentally regulated genes in Drosophila". Proceedings of the National Academy of Sciences of the United States of America. 91 (22): 10717–10721. Bibcode:1994PNAS...9110717Z. doi:10.1073/pnas.91.22.10717. PMC 45093. PMID 7938017.
  3. ^ a b Bardwell VJ, Treisman R (July 1994). "The POZ domain: a conserved protein-protein interaction motif". Genes & Development. 8 (14): 1664–1677. doi:10.1101/gad.8.14.1664. PMID 7958847. S2CID 27334252.
  4. ^ a b c d Stogios PJ, Downs GS, Jauhal JJ, Nandra SK, Privé GG (2005-09-15). "Sequence and structural analysis of BTB domain proteins". Genome Biology. 6 (10): R82. doi:10.1186/gb-2005-6-10-r82. PMC 1257465. PMID 16207353.
  5. ^ a b c Perez-Torrado R, Yamada D, Defossez PA (December 2006). "Born to bind: the BTB protein-protein interaction domain". BioEssays. 28 (12): 1194–1202. doi:10.1002/bies.20500. PMID 17120193. S2CID 23248814.
  6. ^ Melnick A, Ahmad KF, Arai S, Polinger A, Ball H, Borden KL, et al. (September 2000). "In-depth mutational analysis of the promyelocytic leukemia zinc finger BTB/POZ domain reveals motifs and residues required for biological and transcriptional functions". Molecular and Cellular Biology. 20 (17): 6550–6567. doi:10.1128/MCB.20.17.6550-6567.2000. PMC 86130. PMID 10938130.
  7. ^ Bomont P, Cavalier L, Blondeau F, Ben Hamida C, Belal S, Tazir M, et al. (November 2000). "The gene encoding gigaxonin, a new member of the cytoskeletal BTB/kelch repeat family, is mutated in giant axonal neuropathy". Nature Genetics. 26 (3): 370–374. doi:10.1038/81701. PMID 11062483. S2CID 2917153.
  8. ^ Furukawa M, He YJ, Borchers C, Xiong Y (November 2003). "Targeting of protein ubiquitination by BTB-Cullin 3-Roc1 ubiquitin ligases". Nature Cell Biology. 5 (11): 1001–1007. doi:10.1038/ncb1056. PMID 14528312. S2CID 22937928.
  9. ^ Pintard L, Willis JH, Willems A, Johnson JL, Srayko M, Kurz T, et al. (September 2003). "The BTB protein MEL-26 is a substrate-specific adaptor of the CUL-3 ubiquitin-ligase". Nature. 425 (6955): 311–316. Bibcode:2003Natur.425..311P. doi:10.1038/nature01959. PMID 13679921. S2CID 4425748.
  10. ^ Geyer R, Wee S, Anderson S, Yates J, Wolf DA (September 2003). "BTB/POZ domain proteins are putative substrate adaptors for cullin 3 ubiquitin ligases". Molecular Cell. 12 (3): 783–790. doi:10.1016/s1097-2765(03)00341-1. PMID 14527422.
  11. ^ Minor DL, Lin YF, Mobley BC, Avelar A, Jan YN, Jan LY, Berger JM (September 2000). "The polar T1 interface is linked to conformational changes that open the voltage-gated potassium channel". Cell. 102 (5): 657–670. doi:10.1016/s0092-8674(00)00088-x. PMID 11007484. S2CID 776305.
  12. ^ Bonchuk A, Balagurov K, Georgiev P (February 2023). "BTB domains: A structural view of evolution, multimerization, and protein-protein interactions". BioEssays. 45 (2): e2200179. doi:10.1002/bies.202200179. PMID 36449605. S2CID 254122488.
This article incorporates text from the public domain Pfam and InterPro: IPR013069