BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain superfamily; Proteins in this superfamily are characterized by the presence of a common protein-protein interaction motif of about 100 amino acids, known as the BTB/POZ domain. Members include transcription factors, oncogenic proteins, ion channel proteins, and potassium channel tetramerization domain (KCTD) proteins. They have been identified in poxviruses and many eukaryotes, and have diverse functions, such as transcriptional regulation, chromatin remodeling, protein degradation and cytoskeletal regulation. Many BTB/POZ proteins contain one or two additional domains, such as kelch repeats, zinc-finger domains, FYVE (Fab1, YOTB, Vac1, and EEA1) fingers, or ankyrin repeats, among others. These special additional domains or interaction partners provide unique characteristics and functions to BTB/POZ proteins. In ion channel proteins and KCTD proteins, the BTB/POZ domain is also called the tetramerization (T1) domain.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182  89 GNASDVVLRVQavgtdeVRAFHTHRLLLGLHSELFRELLSN-------QSEVVLQEPGDCAAVFDKFIRYLYCGELTVLL 161
Cdd:cd18292   15 EELSDIVLRVG------GKVFHAHRLILAKSSDVFRVMLSNdwwseskQSEIELVEDPECAAVFEKFLRYLYTGQISVNL 88

                         90       100
                 ....*....|....*....|....*.
gi 197385182 162 AQAIPLHRLATKYRVASLQRGVADYM 187
Cdd:cd18292   89 ETALPLLMLADKYNVTDLKQLCVDFM 114

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in BTB/POZ domain-containing protein 17 (BTBD17); BTBD17, also called galectin-3-binding protein-like, is a BTB domain-containing protein. Its function remains unclear. It may be associated with hepatocellular carcinoma. The BTB/POZ domain is a common protein-protein interaction motif of about 100 amino acids.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182  89 GNASDVVLRVQavgtdeVRAFHTHRLLLGLHSELFRELLSN-------QSEVVLQEPGDCAAVFDKFIRYLYCGELTVLL 161
Cdd:cd18292   15 EELSDIVLRVG------GKVFHAHRLILAKSSDVFRVMLSNdwwseskQSEIELVEDPECAAVFEKFLRYLYTGQISVNL 88

                         90       100
                 ....*....|....*....|....*.
gi 197385182 162 AQAIPLHRLATKYRVASLQRGVADYM 187
Cdd:cd18292   89 ETALPLLMLADKYNVTDLKQLCVDFM 114

BTB And C-terminal Kelch; This domain is found associated with pfam00651 and pfam01344. The BACK domain is found juxtaposed to the BTB domain; they are separated by as little as two residues. This family appears to be closely related to the BTB domain (Finn RD, personal observation).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182  198 AVGWYHYAVSTGDEALRESCLQFLAWNLSAVAGSAEWGAVSPELLAQLLQRSDLVLQDELELFHALEAWLGRTRPP-PTV 276
Cdd:pfam07707   1 CLGIYRFADAYGCTELAEAALRFILQNFLEVAKSEEFLELSLEQLLELLSSDDLNVPSEEEVFEAVIRWVKHDVERrKKH 80

                          90       100
                  ....*....|....*....|...
gi 197385182  277 AERALRAIRYPMIPPAQLFQLQA 299
Cdd:pfam07707  81 LPELLSAVRLPLLSPQYLLNLVE 103

Broad-Complex, Tramtrack and Bric a brac; 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.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182    93 DVVLRVqavgtdEVRAFHTHRLLLGLHSELFRELLSN------QSEVVLQEpgDCAAVFDKFIRYLYCGELTVLLAQAIP 166
Cdd:smart00225   1 DVTLVV------GGKKFHAHKAVLAAHSPYFKALFSSdfkesdKSEIYLDD--VSPEDFRALLNFLYTGKLDLPEENVEE 72

                           90       100
                   ....*....|....*....|....*
gi 197385182   167 LHRLATKYRVASLQRGVADYMRAHL 191
Cdd:smart00225  73 LLELADYLQIPGLVELCEEFLLKLL 97

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in BTB/POZ domain-containing protein 17 (BTBD17); BTBD17, also called galectin-3-binding protein-like, is a BTB domain-containing protein. Its function remains unclear. It may be associated with hepatocellular carcinoma. The BTB/POZ domain is a common protein-protein interaction motif of about 100 amino acids.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182  89 GNASDVVLRVQavgtdeVRAFHTHRLLLGLHSELFRELLSN-------QSEVVLQEPGDCAAVFDKFIRYLYCGELTVLL 161
Cdd:cd18292   15 EELSDIVLRVG------GKVFHAHRLILAKSSDVFRVMLSNdwwseskQSEIELVEDPECAAVFEKFLRYLYTGQISVNL 88

                         90       100
                 ....*....|....*....|....*.
gi 197385182 162 AQAIPLHRLATKYRVASLQRGVADYM 187
Cdd:cd18292   89 ETALPLLMLADKYNVTDLKQLCVDFM 114

BACK (BTB and C-terminal Kelch) domain found in lectin galactoside-binding soluble 3-binding protein (LGALS3BP); LGALS3BP, also called galectin-3-binding protein, or basement membrane autoantigen p105, or Mac-2-binding protein (MAC2BP/M2BP), or tumor-associated antigen 90K, promotes integrin-mediated cell adhesion. It may stimulate host defense against viruses and tumor cells.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182 198 AVGWYHYAVSTGDEALRESCLQFLAWNLSAVAGSAEWGAVSPELLAQLLQRSDLVLQDELELFHALEAWL 267
Cdd:cd18496    5 QLSLYEYALSTGDALLRGLCLQYLAWNCEALISSEAWLDLPWDQLKALLTRSDLVVPDELVLLKALEAWA 74

BTB And C-terminal Kelch; The BACK domain is found juxtaposed to the BTB domain; they are separated by as little as two residues.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182   198 AVGWYHYAVSTGDEALRESCLQFLAWNLSAVAGSAEWGAVSPELLAQLLQRSDLVLQDELELFHALEAWLGRTRPP-PTV 276
Cdd:smart00875   1 CLGIRRFADAHGLEELAEKALRFILQNFSEVSSSEEFLELPLEQLLELLSSDDLNVSSEEEVFEAVLRWVKHDPEKrREH 80

                           90       100
                   ....*....|....*....|
gi 197385182   277 AERALRAIRYPMIPPAQLFQ 296
Cdd:smart00875  81 LPELLEHVRLPLLSPDYLLE 100

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in BTB/POZ domain-containing protein 9 (BTBD9); BTBD9 is a risk factor for Restless Legs Syndrome (RLS) encoding a Cullin-3 substrate adaptor. The BTBD9 gene may be associated with antipsychotic-induced RLS in schizophrenia. Mutations in BTBD9 lead to reduced dopamine, increased locomotion and sleep fragmentation. The BTB/POZ domain is a common protein-protein interaction motif of about 100 amino acids.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182  72 INHSHMLLQRLQDLLRHGNASDVVLRVqavgtDEVRaFHTHRLLLGLHSELFRELL------SNQSEVVLQEPGdcAAVF 145
Cdd:cd18287    3 IDHVHFLSEDIGALFLNEEYSDVTFVV-----EEKR-FPAHRVILAARSEYFRALLyggmreSQQSEIELKDTN--AEAF 74

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....
gi 197385182 146 DKFIRYLYCGELTVLLAQA---IPLHRLATKYRVASLQRGVADY 186
Cdd:cd18287   75 KALLKYIYTGRLTLTDLKEdvlLDVLGLAHQYGFEELEAAISDY 118

BTB/POZ domain; The BTB (for BR-C, ttk and bab) or POZ (for Pox virus and Zinc finger) domain is present near the N-terminus of a fraction of zinc finger (pfam00096) proteins and in proteins that contain the pfam01344 motif such as Kelch and a family of pox virus proteins. The BTB/POZ domain mediates homomeric dimerization and in some instances heteromeric dimerization. The structure of the dimerized 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. 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. The POZ or BTB domain is also known as BR-C/Ttk or ZiN.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182   92 SDVVLRVQAvgtdevRAFHTHRLLLGLHSELFRELLSNQ---SEVVLQEPGDC-AAVFDKFIRYLYCGELtVLLAQAIPL 167
Cdd:pfam00651  11 CDVTLVVGD------KEFRAHKAVLAACSPYFKALFSGQeseSSVSEITLDDVsPEDFEALLEFMYTGKL-ISEENVDDL 83

                          90       100
                  ....*....|....*....|....
gi 197385182  168 HRLATKYRVASLQRGVADYMRAHL 191
Cdd:pfam00651  84 LAAADKLQIPSLVDKCEEFLIKSL 107

first BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Ankyrin repeat and BTB/POZ domain-containing protein 1 (ABTB1); ABTB1, also called elongation factor 1A-binding protein or bood POZ containing gene type 1 (BPOZ-1), is an anti-proliferative factor that may act as a mediator of the phosphatase and tensin homolog (PTEN) growth-suppressive signaling pathway. It may play a role in developmental processes. ABTB1 contains an ankyrin repeat and two BTB domains. This model corresponds to the first BTB domain. The BTB/POZ domain is a common protein-protein interaction motif of about 100 amino acids.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182  89 GNASDVVLRVQAvgtdevRAFHTHRLLLGLHSELFRELLS----NQSEVVLQEPGDCAAVFDKFIRYLYCGELTVLLAQA 164
Cdd:cd18295   17 GSYSDVTFNVHG------ESFPAHRCILSARSPYFAEMFEtkwkDKREINLKHPLVNPDAFRALLQYLYTGRLEIHVDDV 90

                         90       100
                 ....*....|....*....|....*...
gi 197385182 165 IPLHRLATKYRVASLQRGVADYMRAHLA 192
Cdd:cd18295   91 EDCKRLAKQCRLEELIEELEAKCKKVRE 118

BACK (BTB and C-terminal Kelch) domain; The BACK domain is found in architectures C-terminal to a BTB domain, in a diverse set of architectures together with Kelch, MATH, and/or TAZ domains. It is involved in interactions with the Cullin3 (Cul3) ubiquitin ligase complex, as well as in homo-oligomerization. Most proteins containing the BACK domain are understood to function as adaptor proteins that play a role in ubiquitination of various substrates.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 197385182 198 AVGWYHYAVSTGDEALRESCLQFLAWNLSAVAGSAEWGAVSPELLAQLLQR 248
Cdd:cd14733    5 CLGILELADLYNLEELKEKALKFILENFEEVSKSEEFLELSVELLLELLSS 55

BACK (BTB and C-terminal Kelch) domain found in Drosophila melanogaster protein germ cell-less (GCL) and similar proteins; The GCL protein is a nuclear envelope protein highly conserved between the mammalian and Drosophila orthologs. Drosophila melanogaster GCL is a key regulator required for the specification of pole cells and primordial germ cell formation in Drosophila embryos. Both human germ cell-less protein-like 1 (GMCL1) and germ cell-less protein-like 1-like (GMCL1P1 or GMCL1L) may function in spermatogenesis. They may also be substrate-specific adaptors of an E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 197385182 199 VGWYHYAVST-GDEALRESCLQFLAWNLSAVAGSAEWGAVSPELLAQLLQRSDL-VLQDELELFHALEAWL 267
Cdd:cd18495    6 VCSYYEAACMyGLTEVKKKCLEWLLRNLMTSQNVTLLRELSIELMEQLIASPNLfVMQVEMDVYTLLKKWL 76

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in BTB/POZ domain-containing protein 19 (BTBD19); BTBD19 is a BTB domain-containing protein. Its function remains unclear. The BTB/POZ domain is a common protein-protein interaction motif of about 100 amino acids.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182  92 SDVVLRVqavgTDEVRAFHTHRLLLGLHSELFRELL-------SNQSEVVLQEPGdcAAVFDKFIRYLYCGELTVLLAQA 164
Cdd:cd18294   15 SDVKFLV----GPERQEIFAHKCILAARCEVFRAMFltgpqkeSTQSPLVLSDIE--PEVFRAVLEFIYTNCVTLSNHTV 88

                         90       100
                 ....*....|....*....|...
gi 197385182 165 IPLHRLATKYRVASLQRGVADYM 187
Cdd:cd18294   89 IEVLAAAVEYGLDELRKLCERFI 111

BACK (BTB and C-terminal Kelch) domain found in BTB/POZ domain-containing protein 9 (BTBD9); BTBD9 is a risk factor for Restless Legs Syndrome (RLS) encoding a Cullin-3 substrate adaptor. The BTBD9 gene may be associated with antipsychotic-induced RLS in schizophrenia. Mutations in BTBD9 lead to reduced dopamine, increased locomotion and sleep fragmentation.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182 211 EALRESCLQFLAWNLSAVAGSAEWGAVSPELLAQLLQRsDLVLQDELELFHALEAWLgRTRPPPTVAERA-LRAIRYPMI 289
Cdd:cd14822   19 DDLCQTCCQFMDRNAQEVLSSEGFLTLSKSALKELLSR-DSFCAPEVDIFNAVRRWC-EHNPDSKEDAKEiLEAVRLPLM 96

                 ....*
gi 197385182 290 PPAQL 294
Cdd:cd14822   97 SLTEL 101

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Influenza virus NS1A-binding protein (NS1-BP); NS1-BP is also called NS1-binding protein, aryl hydrocarbon receptor-associated protein 3 (ARA3), or IVNS1ABP. It is a novel protein that interacts with the influenza A virus nonstructural NS1 protein, which is relocalized in the nuclei of infected cells. It plays a role in cell division and in the dynamic organization of the actin skeleton as a stabilizer of actin filaments by association with F-actin through its kelch repeats. It also interacts with alpha-enolase/MBP-1 and is involved in c-Myc gene transcriptional control. NS1-BP contains BTB and BACK domains at the N-terminal region and kelch repeats at the C-terminal region. The BTB/POZ domain is a common protein-protein interaction motif of about 100 amino acids.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182  93 DVVLRVqavGTDEVRAfhtHRLLLGLHSELFRELLSNQSE-----VVLQEPGDCAAvFDKFIRYLYCGELTVLLAQAIPL 167
Cdd:cd18306   20 DVILQV---GGHEIPA---HRAVLACASPYLFELFSSDSDgesilTVKLDGLDPDA-VEVLVNYAYTSRLEVPADLVKSV 92

                         90       100
                 ....*....|....*....|....
gi 197385182 168 HRLATKYRVASLQRGVADYMRAHL 191
Cdd:cd18306   93 YSAAKKLKMDRVKKACGDFLLEKL 116

BACK (BTB and C-terminal Kelch) domain found in Kelch-like proteins, KLHL9 and KLHL13; KLHL9 and KLHL13 (also termed BTB and kelch domain-containing protein 2, or BKLHD2) are substrate-specific adaptors of a BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex required for mitotic progression and cytokinesis. The BCR(KLHL9-KLHL13) E3 ubiquitin ligase complex mediates the ubiquitination of AURKB and controls the dynamic behavior of AURKB on mitotic chromosomes and thereby coordinates faithful mitotic progression and completion of cytokinesis.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 197385182 220 FLAWNLSAVAGSAEWGAVSPELLAQLLQRSDLVLQDELELFHALEAWLGRTRPPPTVAERALRAIRYP 287
Cdd:cd18449   28 FILKNFPALLSTGDFVKLPFERLAFVLSSNSLKGCTELELFKAACRWLRHEDDRMQFAAKLMENIRFP 95

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Kelch repeat and BTB domain-containing protein 8 (KBTBD8); KBTBD8, also called T-cell activation kelch repeat protein (TA-KRP), is a BTB-kelch family protein that is located in the Golgi apparatus and translocates to the spindle apparatus during mitosis. It acts as a substrate-specific adaptor of a BCR (BTB-CUL3-RBX1) E3 ubiquitin ligase complex that acts as a regulator of neural crest specification. The BCR(KBTBD8) complex monoubiquitylates NOLC1 and its paralog TCOF1, the mutation of which underlies the neurocristopathy Treacher Collins syndrome. The BTB/POZ domain is a common protein-protein interaction motif of about 100 amino acids.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182  89 GNASDVVLRVqavgtDEVRAFHTHRLLLGLHSELFRELL------SNQSEVVLQepGDCAAVFDKFIRYLYCGELTVLLA 162
Cdd:cd18274   20 GQLTDIVVEV-----DHGKTFSCHRNVLAAISPYFRSMFtsglteSTQKEVRIV--GVEAESMHLVLDYAYTSRVTLTEA 92

                         90       100
                 ....*....|....*....|....*....
gi 197385182 163 QAIPLHRLATKYRVASLQRGVADYMRAHL 191
Cdd:cd18274   93 NVQALFTAASIFQIPSLQDQCAQFMISRL 121

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Kelch-like protein 41 (KLHL41); KLHL41 is also called Kel-like protein 23, Kelch repeat and BTB domain-containing protein 10 (KBTBD10), Kelch-related protein 1 (Krp1), or sarcosine. It is a novel kelch-related protein that is involved in pseudopod elongation in transformed cells. It is also involved in skeletal muscle development and differentiation. It regulates proliferation and differentiation of myoblasts and plays a role in myofibril assembly by promoting lateral fusion of adjacent thin fibrils into mature, wide myofibrils. It contains a BTB domain and kelch repeats, characteristics of a kelch family protein. The BTB/POZ domain is a common protein-protein interaction motif of about 100 amino acids.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 197385182 107 RAFHTHRLLLGLHSELFREL-LSNQSE-----VVLQ--EPgdcaAVFDKFIRYLYCGELTVLLAQAIPLHRLATKYRVAS 178
Cdd:cd18341   37 KSLPCHRLILAACSPYFREYfLSEESEekkkeVVLDnvDP----NIMDMILKYLYSAEIDLNDGNVQDIFALASRFQIPS 112

                         90
                 ....*....|....*.
gi 197385182 179 LQRGVADYMRAHLAGG 194
Cdd:cd18341  113 VFTVCVTYLQKRLSPA 128