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
                  ....*....|....*....|....*....|...
gi 1063678547 107 NVLDILELASIPCDTILKDAAINHIVKHMEEVV 139
Cdd:cd14733     4 NCLGILELADLYNLEELKEKALKFILENFEEVS 36

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 1063678547   2 HTDVLVKPGEEapPIPTHKAVLAARSKVFRNMLDSDECKtSPEESITLPDLSHDELKSLLEFLYSGNLKAPYNqYRSLYL 81
Cdd:pfam00651  10 LCDVTLVVGDK--EFRAHKAVLAACSPYFKALFSGQESE-SSVSEITLDDVSPEDFEALLEFMYTGKLISEEN-VDDLLA 85

                          90       100
                  ....*....|....*....|..
gi 1063678547  82 AADKYDISYLQDVCRNHFIASL 103
Cdd:pfam00651  86 AADKLQIPSLVDKCEEFLIKSL 107

kelch-like protein; Provisional

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063678547  16 IPTHKAVLAARSKVFRNMLdsdeCKTSPEESITLPDlSHDELKSLLEFLYSGNLKAPYNQYRSLYLAADKYDISYLQDVC 95
Cdd:PHA03098   23 IKVHKIILSSSSEYFKKMF----KNNFKENEINLNI-DYDSFNEVIKYIYTGKINITSNNVKDILSIANYLIIDFLINLC 97

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|.
gi 1063678547  96 RNHFIASLSSRNVLDILELASIPCDTILKDAAINHIVKHME 136
Cdd:PHA03098   98 INYIIKIIDDNNCIDIYRFSFFYGCKKLYSAAYNYIRNNIE 138

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 1063678547   2 HTDVLVKPGEEapPIPTHKAVLAARSKVFRNMLDSDECKtSPEESITLPDLSHDELKSLLEFLYSGNLKAPYNqYRSLYL 81
Cdd:pfam00651  10 LCDVTLVVGDK--EFRAHKAVLAACSPYFKALFSGQESE-SSVSEITLDDVSPEDFEALLEFMYTGKLISEEN-VDDLLA 85

                          90       100
                  ....*....|....*....|..
gi 1063678547  82 AADKYDISYLQDVCRNHFIASL 103
Cdd:pfam00651  86 AADKLQIPSLVDKCEEFLIKSL 107

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 1063678547   1 MHTDVLVKPGEEAPPIPTHKAVLAARSKVFRNMLDSDECKTSPEESITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLY 80
Cdd:cd18294    13 EFSDVKFLVGPERQEIFAHKCILAARCEVFRAMFLTGPQKESTQSPLVLSDIEPEVFRAVLEFIYTNCVTLSNHTVIEVL 92

                          90       100
                  ....*....|....*....|
gi 1063678547  81 LAADKYDISYLQDVCRnHFI 100
Cdd:cd18294    93 AAAVEYGLDELRKLCE-RFI 111

BTB (Broad-Complex, Tramtrack and Bric a brac) /POZ (poxvirus and zinc finger) domain found in Drosophila melanogaster proteins bric-a-brac 1 (BAB1), bric-a-brac 2 (BAB2), modifier of mdg4 (doom), and similar proteins; BAB1 and BAB2 probably act as transcriptional regulators that are required for specification of the tarsal segment and are involved in antenna development. Doom is a product of the Drosophila mod(mdg4) gene. It induces apoptosis and binds to baculovirus inhibitor-of-apoptosis proteins. This subfamily also includes Drosophila melanogaster sex determination protein fruitless (FRU), protein jim lovell (LOV), zinc finger protein chinmo, transcription factor GAGA, transcription factor Ken, and longitudinals lacking proteins (LOLA). FRU probably acts as a transcriptional regulator that plays a role in male courtship behavior and sexual orientation, and enhances male-specific expression of takeout in brain-associated fat body. LOV, also called tyrosine kinase-related (TKR), has a regulatory role during midline cell development. Chinmo is a functional effector of the JAK/STAT pathway that regulates eye development, tumor formation, and stem cell self-renewal in Drosophila. GAGA is a transcriptional activator that functions by regulating chromatin structure. Ken, also termed protein Ken and Barbie, is a transcription factor required for Terminalia development. LOLA proteins are putative transcription factors required for axon growth and guidance in the central and peripheral nervous systems. Proteins in this subfamily contain a BTB domain. The BTB/POZ domain is a common protein-protein interaction motif of about 100 amino acids.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1063678547  16 IPTHKAVLAARSKVFRNMLDSDECKTSPEesITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLYLAA 83
Cdd:cd18315    13 LKAHKLVLAAASPYFAALLKETPPDEHPV--IILPDVPYSELKALLDFIYTGEVNVSQEQLESLLKLA 78

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in TD and POZ domain-containing proteins (TDPOZ); TDPOZ is a family of bipartite animal and plant proteins that contains a tumor necrosis factor receptor-associated factor (TRAF) domain (TD) and a POZ/BTB domain. TDPOZ proteins may be nuclear scaffold proteins probably involved in transcription regulation in early development and other cellular processes. This subfamily contains only mammalian members. Plant TDPOZ proteins contain a MATH domain at the N-terminal region and are named "BTB/POZ and MATH domain-containing proteins (BPM)", not included in this subfamily. 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 1063678547  19 HKAVLAARSKVFRNMLDsDECKTSPEESITLPDLSHDELKSLLEFLYSGnlKAPYNQYRS----LYLAADKYDISYLQDV 94
Cdd:cd18344    38 HKAILAARSPVFRAMFE-HEMEERLKNPIEIHDLDPQVFKEMMGFIYTG--KAPHLHSHSmacdVLAAADKYGLEGLKVL 114

                          90
                  ....*....|...
gi 1063678547  95 CRNHFIASLSSRN 107
Cdd:cd18344   115 CEDALCRNLSVEN 127

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in speckle-type POZ protein (SPOP) and similar proteins; This family includes speckle-type POZ protein (SPOP), speckle-type POZ protein-like (SPOPL), TD and POZ domain-containing proteins (TDPOZ), Drosophila melanogaster protein roadkill and similar proteins. Both, SPOP and SPOPL, serve as adaptors of cullin-RING-based BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complexes that mediate the ubiquitination and proteasomal degradation of target proteins. TDPOZ is a family of bipartite animal and plant proteins that contain a tumor necrosis factor receptor-associated factor (TRAF) domain (TD) and a POZ/BTB domains. TDPOZ proteins may be nuclear scaffold proteins probably involved in transcription regulation in early development and other cellular processes. Drosophila melanogaster protein roadkill, also called Hh-induced MATH and BTB domain-containing protein (HIB), is a hedgehog-induced BTB protein that modulates hedgehog signaling by degrading Ci/Gli transcription factor. 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 1063678547  19 HKAVLAARSKVFRNMLDSdECKTSPEESITLPDLSHDELKSLLEFLYSGnlKAPYNQYRS--LYLAADKYDISYLQDVCR 96
Cdd:cd18279    33 HKAILAARSPVFSAMFEH-EMEESKKNRVEINDVDPEVFKEMMRFIYTG--KAPNLDKMAddLLAAADKYALERLKVMCE 109

                          90
                  ....*....|.
gi 1063678547  97 NHFIASLSSRN 107
Cdd:cd18279   110 DALCSNLSVEN 120

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 1063678547   4 DVLVKPGEEAppIPTHKAVLAARSKVFRNMLDSDECKTSPEESITL--PDLSHDELKSLLEFLYSGNLKAPYNQYRSLYL 81
Cdd:cd18292    19 DIVLRVGGKV--FHAHRLILAKSSDVFRVMLSNDWWSESKQSEIELveDPECAAVFEKFLRYLYTGQISVNLETALPLLM 96

                          90
                  ....*....|....
gi 1063678547  82 AADKYDISYLQDVC 95
Cdd:cd18292    97 LADKYNVTDLKQLC 110

second BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Rho-related BTB domain-containing proteins (RhoBTB); RhoBTB proteins constitute a subfamily of atypical members within the Rho family of small guanosine triphosphatases (GTPases), which is characterized by containing a GTPase domain (in most cases, non-functional) followed by a proline-rich region, a tandem of 2 BTB domains, and a conserved C-terminal region. In humans, the RhoBTB subfamily consists of 3 isoforms: RhoBTB1, RhoBTB2, and RhoBTB3. Orthologs are present in several other eukaryotes, such as Drosophila and Dictyostelium, but have been lost in plants and fungi. This model corresponds to the second 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 1063678547  15 PIPTHKAVLAARSKVFRNMLdSDECKTSPEESITLPDLSHDELKSLLEFLYSGNLKAPYN-QYRSLYLAADKYDISYLQD 93
Cdd:cd18300    20 TIPAHKALLVARCDVMAAMF-GGNFRESSAKEVELPGVSKETFLALLEYLYTDQAPILEDgDCVGLIVLANRLCLPRLVA 98

                          90
                  ....*....|
gi 1063678547  94 VCRNHFIASL 103
Cdd:cd18300    99 LCEQYIVKEL 108

second BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in BTB/POZ domain-containing protein 8 (BTBD8); BTBD8 is a BTB-domain-containing Kelch-like protein that may play a role in developmental processes. It may also act as a protein-protein adaptor in a transcription complex and thus be involved in brain development. BTBD8 contains two BTB domains. This model corresponds to the second 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 1063678547   2 HTDVLVKPGEEapPIPTHKAVLAARSKVFRNMLDSDECKTSPEEsITLPDLSHDELKSLLEFLYSGNLKAPYNQ-YRSLY 80
Cdd:cd18286    17 DSDITIKVDGK--TFKAHRCILCARSSYFAAMLSGSWAESNSSE-ITLTGVSHAAVSFVLLFIYGGVLDLPDDVnLGELL 93

                          90
                  ....*....|....
gi 1063678547  81 LAADKYDISYLQDV 94
Cdd:cd18286    94 SLADMYGLDGLKDV 107

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in BTB/POZ domain-containing proteins, BTBD1 and BTBD2; This family includes BTB/POZ domain-containing proteins BTBD1 and BTBD2, both of which are BTB-domain-containing Kelch-like proteins that interact with DNA topoisomerase 1 (Topo1), a key enzyme of cell survival. BTBD1 and BTBD2 colocalize to cytoplasmic bodies with the RBCC/tripartite motif protein, TRIM5delta. 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 1063678547  16 IPTHKAVLAARSKVFRNMLDSDECKTSPEesITLPDLSHDELKSLLEFLYSGNLK-APYNQYRSLYlAADKYDISYLQDV 94
Cdd:cd18281    38 IPAHKFVLSIGSAVFDAMFNGGMATTSAE--IELPDVEPAAFLALLRFLYSDEVQiGPETVMTTLY-TAKKYAVPALESA 114

                          90
                  ....*....|...
gi 1063678547  95 CRNHFIASLSSRN 107
Cdd:cd18281   115 CVEFLKKNLSSDN 127

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in BTB/POZ domain-containing protein 1 (BTBD1); BTBD1, also called Hepatitis C virus NS5A-transactivated protein 8 or HCV NS5A-transactivated protein 8, is a BTB-domain-containing Kelch-like protein that is expressed in skeletal muscle and interacts with DNA topoisomerase 1 (Topo1), a key enzyme of cell survival. BTBD1 and BTBD2 colocalize to cytoplasmic bodies with the RBCC/tripartite motif protein, TRIM5delta. BTBD1 may serve as substrate-specific adaptor of an E3 ubiquitin-protein ligase complex that mediates the ubiquitination and subsequent proteasomal degradation of target proteins. 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 1063678547   9 PGEEAPPIPTHKAVLAARSKVFRNMLDSDECKTSPEesITLPDLSHDELKSLLEFLYSGNLK-APYNQYRSLYlAADKYD 87
Cdd:cd18346    37 PGPGAQRIPAHRFVLAAGSAVFDAMFNGGMATTSAE--IELPDVEPAAFLALLRFLYSDEVQiGPETVMTTLY-TAKKYA 113

                          90       100
                  ....*....|....*....|
gi 1063678547  88 ISYLQDVCRNHFIASLSSRN 107
Cdd:cd18346   114 VPALEAHCVEFLTKHLRADN 133

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in speckle-type POZ protein (SPOP); SPOP, also called HIB homolog 1 or Roadkill homolog 1, is a novel nuclear speckle-type protein which serves as an adaptor of a cullin-RING-based BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex that mediates the ubiquitination and proteasomal degradation of target proteins, such as BRMS1, DAXX, PDX1/IPF1, GLI2 and GLI3. 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 1063678547  19 HKAVLAARSKVFRNMLDSdECKTSPEESITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLYLAADKYDISYLQDVCRNH 98
Cdd:cd18342    37 HKAILAARSPVFSAMFEH-EMEESKKNRVEINDVEPEVFKEMMCFIYTGKAPNLDKMADDLLAAADKYALERLKVMCEDA 115

                  ....*....
gi 1063678547  99 FIASLSSRN 107
Cdd:cd18342   116 LCSNLSVEN 124

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Kelch-like protein 35 (KLHL35); KLHL35 contains a BTB domain and kelch repeats, characteristics of a kelch family protein. Its function remains unclear. Significant differences in DNA methylation of the KLHL35 gene in abdominal aortic aneurysm (AAA) patients compared to non-AAA controls suggest a potential role in AAA pathology. Hypermethylation of the KLHL35 gene has also been associated with the development of 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 1063678547   3 TD-VLVKPGEEappIPTHKAVLAARSKVFRNMLDSdECKTSPEESITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLYL 81
Cdd:cd18265    24 TDvVLLVDGKD---FPCHRATLSANSAYFRAMFGG-HLKESRQAVVEIQKVSAAAMEVLLDYMYGGGLRIQEDNVESVLE 99

                          90
                  ....*....|....
gi 1063678547  82 AADKYDISYLQDVC 95
Cdd:cd18265   100 ASDLLQVSKLREAC 113

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Kelch repeat and BTB domain-containing protein 3 (KBTBD3); KBTBD3, also called BTB and kelch domain-containing protein 3 (BKLHD3), contains a BTB domain and kelch repeats, characteristics of a kelch family 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 1063678547  16 IPTHKAVLAARSKVFRNMLDSDeCKTSPEESITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLYLAADKYDISYLQDVC 95
Cdd:cd18271    36 IPCHRCVLAACSDFFRAMFEVN-MKERDDGSVTISNLSPKAVKAFLDYAYTGKAEITDDNVEMFFQMSSFLQVSLLSKAC 114

                          90
                  ....*....|....*.
gi 1063678547  96 RNHFIASLSSRNVLDI 111
Cdd:cd18271   115 SDFLIKSIDLTNCLQL 130

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in BTB/POZ domain-containing protein 6 (BTBD6); BTBD6, also termed lens BTB domain protein, is a BTB-domain-containing Kelch-like protein required for proper embryogenesis and plays an essential evolutionary conserved role during neuronal development. 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 1063678547   6 LVKPGEEAPPIPTHKAVLAARSKVFRNMLDSDECKTSPEesITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLYLAADK 85
Cdd:cd18349    14 IVGPPGASQRVPAHKYVLAVGSSVFYAMFYGDLAEVKSE--IHIPDVEPAAFLILLKYMYSDEIDLEADTVLATLYAAKK 91

                          90
                  ....*....|....*...
gi 1063678547  86 YDISYLQDVCRNHFIASL 103
Cdd:cd18349    92 YIVPALAKACVNFLETSL 109

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Kelch-like protein 8 (KLHL8); KLHL8 is a substrate-specific adaptor of a BCR (BTB-CUL3-RBX1) E3 ubiquitin ligase complex required for the ubiquitination and degradation of rapsyn, a postsynaptic protein required for clustering of nicotinic acetylcholine receptors (nAChRs) at the neuromuscular junction. 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 1063678547   4 DVLVKPGEEAppIPTHKAVLAARSKVFRNMLDSD--ECKtspEESITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLYL 81
Cdd:cd18238    17 DVTLKVGEKS--IHCHRLVLACVSPYFRAMFTSEmaESK---QDSITIKDIDEEAVELLVDFAYTGKLTLTVDNVQSLLY 91

                          90       100
                  ....*....|....*....|..
gi 1063678547  82 AADKYDISYLQDVC----RNHF 99
Cdd:cd18238    92 AASLLQVEEVAKACcefmKDHL 113

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1063678547  16 IPTHKAVLAARSKVFRNMLDSDECKTSPEEsITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLYLAADKY 86
Cdd:cd01165    10 FHVNKELLAQSSEYFRALFRGGFRESGQAE-INLRDISPEDFRALLEFLYGGKRDLDASNLLELLEAANFL 79

BTB (Broad-Complex, Tramtrack and Bric a brac) /POZ (poxvirus and zinc finger) domain found in plant regulatory proteins, NPR1-4, and similar proteins; NPR1 and NPR2 are essential for pathogenicity and the utilization of many nitrogen sources. NPR1 is also called nitrogen pathogenicity regulation protein NPR1, non-inducible immunity protein 1 (Nim1), nonexpresser of PR genes 1, or salicylic acid insensitive 1 (Sai1). It acts as a transcription coactivator that plays dual roles in regulating plant immunity. NPR3 and NPR4 are involved in negative regulation of defense responses against pathogens in plant. NPR proteins contain a BTB domain, DUF3420, ankyrin (ANK) repeats, and a conserved C-terminal domain. The BTB/POZ domain is a common protein-protein interaction motif of about 100 amino acids.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1063678547  11 EEAPPIPTHKAVLAARSKVFRNMLDSDEC-KTSPEESITLPDL------SHDELKSLLEFLYSGNLKAP 72
Cdd:cd18310    26 EGGRPVPVHRCILAARSPFFRDIFASAKAeGANTKPKLELRELipggivGYDAFMLVLSYLYSGRLRLV 94

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in gigaxonin; Gigaxonin, also called Kelch-like protein 16 (KLHL16), may be a cytoskeletal component that directly or indirectly plays an important role in neurofilament architecture. It may also act as a substrate-specific adaptor of an E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins, including tubulin folding cofactor B (TBCB), microtubule-associated protein MAP1B, and glial fibrillary acidic protein (GFAP). Gigaxonin is mutated in giant axonal neuropathy. 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 1063678547   5 VLVKPGEEappIPTHKAVLAARSKVFRNMLDSDECKTSPE-ESITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLYLAA 83
Cdd:cd18245    18 TLVVGGEE---IPVQKNVLAAASPYFRAKLNYNPPKDDGStYKIELEGISVEVMEEILDYIYTGQIKLSEDNIQDIVQAA 94

                          90
                  ....*....|..
gi 1063678547  84 DKYDISYLQDVC 95
Cdd:cd18245    95 DLLLMTDLKDLC 106

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in plant BTB/POZ-MATH (BPM) protein family; The BPM protein family includes Arabidopsis thaliana BTB/POZ and MATH domain-containing proteins, AtBPM1-6, and similar proteins from other plants. BPM protein, also called protein BTB-POZ and MATH domain, may act as a substrate-specific adaptor of an E3 ubiquitin-protein ligase complex (CUL3-RBX1-BTB) which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. 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 1063678547  19 HKAVLAARSKVFRNMLDSdeckTSPEES---ITLPDLSHDELKSLLEFLY------------SGNLKAPYNQYRSLYLAA 83
Cdd:cd18280    29 HKLVLAARSPVFRSMLFG----PMREENegeIVIEDVEPPVFKALLHFIYkdelpddvepagSDSSSLDTTMAQHLLAAA 104

                          90
                  ....*....|....*
gi 1063678547  84 DKYDISYLQDVCRNH 98
Cdd:cd18280   105 DRYALERLRLLCESR 119

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in BTB/POZ domain-containing protein 18 (BTBD18); BTBD18 acts as a specific controller for transcription activation through RNA polymerase II elongation at a subset of genomic PIWI-interacting RNA (piRNA) loci. 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 1063678547   4 DVLVKPGEEAppIPTHKAVLAARSKVFRNMLDSDECKTSPEESITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLYLAA 83
Cdd:cd18293    17 DVLLQAEGES--VPAHCCVLSACSPYLTERLSSEPPPAGQKVVLELQGLKAHTLLKLVDFLYTSELEVSSEEAQDVLAAA 94

                          90
                  ....*....|..
gi 1063678547  84 DKYDISYLQDVC 95
Cdd:cd18293    95 RRLQISELESLC 106

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 1063678547   2 HTDV-LVKPGEEappIPTHKAVLAARSKVFRNML-----DSDECKtspeesITLPDLSHDELKSLLEFLYSGNLKapynq 75
Cdd:cd18287    22 YSDVtFVVEEKR---FPAHRVILAARSEYFRALLyggmrESQQSE------IELKDTNAEAFKALLKYIYTGRLT----- 87

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|
gi 1063678547  76 yrslylaadkydisylqdvcrnhfIASLSSRNVLDILELA 115
Cdd:cd18287    88 ------------------------LTDLKEDVLLDVLGLA 103

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Kelch-like protein 21 (KLHL21); KLHL21 is a substrate-specific adaptor of a BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex required for efficient chromosome alignment and cytokinesis. The BCR(KLHL21) E3 ubiquitin ligase complex regulates localization of the chromosomal passenger complex (CPC) from chromosomes to the spindle midzone in anaphase and mediates the ubiquitination of aurora B. KLHL21 also targets IkappaB kinase-beta to regulate nuclear factor kappa-light chain enhancer of activated B cells (NF-kappaB) signaling negatively. 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 1063678547  12 EAPPIPTHKAVLAARSKVFRNMLdSDECKTSPEESITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLYLAADKYDISYL 91
Cdd:cd18250    29 GGREFPCHRTVLAAASSYFRAMF-AGELRESRADRVVLHGVSAEILGLLLDFSYTGRVTVTQDNVEALLRAADLFQFPSV 107

                  ....
gi 1063678547  92 QDVC 95
Cdd:cd18250   108 KEAC 111

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in glial cell line-derived neurotrophic factor-inducible zinc finger protein 1 (GZF1); GZF1 is also called GDNF-inducible zinc finger protein 1, zinc finger and BTB domain-containing protein 23 (ZBTB23), or zinc finger protein 336 (ZNF336). It is a sequence-specific transcriptional repressor that binds the GZF1 responsive element (GRE), with the consensus sequence of 5'-TGCGCN[TG][CA]TATA-3'. It may play a role in renal branching morphogenesis. It contains a BTB/POZ domain, a common protein-protein interaction motif of about 100 amino acids.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1063678547  19 HKAVLAARSKVFRNMLDSDECKTSPEESITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLYLAADKYDISYLQDVC 95
Cdd:cd18211    44 HKAVLAASSKYFKEVFLNEKISDGKNTNVMLNEIYTADFASFLEFVYTAKVEVEEDRVQRMLEIAEKLKCLDLSETC 120

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in rabankyrin-5 (Rank-5); Rank-5, also called ankyrin repeat and FYVE domain-containing protein 1 (ANKFY1) or ankyrin repeats hooked to a zinc finger motif (ANKHZN), is a Rab5 effector that regulates and coordinates different endocytic mechanisms. It contains an N-terminal BTB domain, followed by a BACK domain, several ankyrin (ANK) repeats and a C-terminal FYVE 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 1063678547   4 DVLVKPGEEAppIPTHKAVLAARSKVFRNMLDSDecktspEESITLPDLSHDELKSLLEFLYSG--NLKAPYNQYRSLYL 81
Cdd:cd18303    20 DITIKLADKS--IPAHKFVLAARSEKWSNENLAS------TNELDLSDISYEVVLALLRWLYTDelDLTLDDEFLLELMK 91

                          90       100
                  ....*....|....*....|....*.
gi 1063678547  82 AADKYDISYLQDVCRNHFIASLSSRN 107
Cdd:cd18303    92 AAKRFQLTDLVERCERALMSSVNVDN 117

second BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Rho-related BTB domain-containing protein 3 (RhoBTB3); RhoBTB3 is an atypical Rho family small guanosine triphosphatase (GTPase) and is a member of the RhoBTB subfamily, which is characterized by containing a GTPase domain (in most cases, non-functional) followed by a proline-rich region, tandem BTB domains, and a conserved C-terminal region. The carboxyl terminal extension that harbors two BTB domains is capable of assembling cullin 3-dependent ubiquitin ligase complexes. RhoBTB3 is a Golgi-associated Rho-related ATPase that regulates the S/G2 transition of the cell cycle by targeting cyclin E for ubiquitylation. It is involved in vesicle trafficking and in targeting proteins for degradation in the proteasome. It binds directly to Rab9 GTPase and functions with Rab9 in protein transport from endosomes to the trans Golgi network. It also promotes proteasomal degradation of Hypoxia-inducible factor alpha (HIFalpha) through facilitating hydroxylation and suppresses the Warburg effect. This model corresponds to the second 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 1063678547  16 IPTHKAVLAARSKVFRNMLDSDECKTspeESITLP--DLSHDELKSLLEFLYSGN-LKAPYNQYRSLYLAADKYDISYLQ 92
Cdd:cd18360    22 VPAHRAVLVARCEVMAAMFNGNYAEA---KSFLVPiyGVSKDTFLSFLEYLYTDScCPASILQAMALLICAEMYQVSRLQ 98

                          90
                  ....*....|.
gi 1063678547  93 DVCRNHFIASL 103
Cdd:cd18360    99 HICELYIITQL 109

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Kelch-like protein 18 (KLHL18); KLHL18 acts as a substrate-specific adaptor for a Cullin3 E3 ubiquitin-protein ligase complex that regulates mitotic entry and ubiquitylates Aurora-A. 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 1063678547   4 DVLVKPGEEAppIPTHKAVLAARSKVFRNMLDSD--ECKtspEESITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLYL 81
Cdd:cd18247    21 DVTLKVGDQK--FSAHRIVLAATIPYFHAMFTHDmvESK---QDEITMQGIEPSALEALINFAYSGRIAIDTSNVQSLLV 95

                          90
                  ....*....|.
gi 1063678547  82 AAdkydiSYLQ 92
Cdd:cd18247    96 GA-----SFLQ 101

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in intracisternal A particle-promoted polypeptide (IPP); IPP, also called Kelch-like protein 27 (KLHL27) or actin-binding protein IPP, is an actin-binding protein that may play a role in organizing the actin cytoskeleton. 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 1063678547   4 DVLVKPGEEAppIPTHKAVLAARSKVFRNMLDSDECKTSpEESITLPDLSHDELKSLLEFLYSGNLKAPYNQYRSLYLAA 83
Cdd:cd18256    22 DVQLQVGMEL--FSVHRLVLAASSPYFAALFAGGMSESS-KDVVQIHGVEPDIFHILLDFIYTGVVEVTVSNVQELLVAA 98

                          90       100
                  ....*....|....*....|....*.
gi 1063678547  84 DKYDISYLQDVCRNHFIASLSSRNVL 109
Cdd:cd18256    99 DMLQLTEVVEICCEFLKGQLHPSNCI 124