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 17531579   193 LENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGtCTNMGGN 272
Cdd:pfam00651   1 LNELREQGELCDVTLVVGDKEFRAHKAVLAACSPYFKALFSGQESESSVSEITLDDVSPEDFEALLEFMYTG-KLISEEN 79

                          90       100
                  ....*....|....*....|....*...
gi 17531579   273 ALDILAAAERFALPGLKNIAEVAMRNGL 300
Cdd:pfam00651  80 VDDLLAAADKLQIPSLVDKCEEFLIKSL 107

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 17531579 303 ETVCKNLAFAEMYGLVDFKKEAIKYICMNANAVINSEGFLRLSrqnPDLIVDI 355
Cdd:cd14733   3 ENCLGILELADLYNLEELKEKALKFILENFEEVSKSEEFLELS---VELLLEL 52

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 17531579   193 LENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGtCTNMGGN 272
Cdd:pfam00651   1 LNELREQGELCDVTLVVGDKEFRAHKAVLAACSPYFKALFSGQESESSVSEITLDDVSPEDFEALLEFMYTG-KLISEEN 79

                          90       100
                  ....*....|....*....|....*...
gi 17531579   273 ALDILAAAERFALPGLKNIAEVAMRNGL 300
Cdd:pfam00651  80 VDDLLAAADKLQIPSLVDKCEEFLIKSL 107

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 17531579    204 DFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTNMGGNALDILAAAERF 283
Cdd:smart00225   1 DVTLVVGGKKFHAHKAVLAAHSPYFKALFSSDFKESDKSEIYLDDVSPEDFRALLNFLYTGKLDLPEENVEELLELADYL 80

                           90
                   ....*....|....*..
gi 17531579    284 ALPGLKNIAEVAMRNGL 300
Cdd:smart00225  81 QIPGLVELCEEFLLKLL 97

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 17531579 303 ETVCKNLAFAEMYGLVDFKKEAIKYICMNANAVINSEGFLRLSrqnPDLIVDI 355
Cdd:cd14733   3 ENCLGILELADLYNLEELKEKALKFILENFEEVSKSEEFLELS---VELLLEL 52

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
                  ....*....|....*....|....*....|....*..
gi 17531579   309 LAFAEMYGLVDFKKEAIKYICMNANAVINSEGFLRLS 345
Cdd:pfam07707   5 YRFADAYGCTELAEAALRFILQNFLEVAKSEEFLELS 41

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 17531579   193 LENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGtCTNMGGN 272
Cdd:pfam00651   1 LNELREQGELCDVTLVVGDKEFRAHKAVLAACSPYFKALFSGQESESSVSEITLDDVSPEDFEALLEFMYTG-KLISEEN 79

                          90       100
                  ....*....|....*....|....*...
gi 17531579   273 ALDILAAAERFALPGLKNIAEVAMRNGL 300
Cdd:pfam00651  80 VDDLLAAADKLQIPSLVDKCEEFLIKSL 107

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in zinc finger and BTB domain-containing (ZBTB) proteins, Kelch-like (KLHL) proteins, and similar proteins; This family includes a variety of BTB/POZ domain-containing proteins, such as zinc finger and BTB domain-containing (ZBTB) proteins and Kelch-like (KLHL) proteins. They 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. These special additional domains or interaction partners provide unique characteristics and functions to BTB/POZ 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 17531579 202 HADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTNMGGNALDILAAAE 281
Cdd:cd18186   1 LCDVTLVVGGREFPAHRAVLAARSPYFRAMFSSGMKESSSSEIELDDVSPEAFEALLDYIYTGELELSEENVEELLAAAD 80

                ..
gi 17531579 282 RF 283
Cdd:cd18186  81 KL 82

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in speckle-type POZ protein-like (SPOPL); SPOPL, also called HIB homolog 2 or Roadkill homolog 2, is a component of a cullin-RING-based BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complexes that mediate the ubiquitination and subsequent proteasomal degradation of target proteins. The complexes may contain homodimeric SPOPL or the heterodimers formed by speckle-type POZ protein (SPOP) and SPOPL, which are less efficient than ubiquitin ligase complexes containing only SPOP. 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 17531579 189 VTKDLENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTN 268
Cdd:cd18343   8 LAEDLGNLWENSRFTDCSLFVGGQEFKAHKSILAARSPVFNAMFEHEMEESKKNRVEINDVDPEVFKEMMRFIYTGKAPN 87

                        90       100       110
                ....*....|....*....|....*....|....*
gi 17531579 269 MGGNALDILAAAERFALPGLKNIAEVAMRNGLATE 303
Cdd:cd18343  88 LDKMADNLLAAADKYALERLKVMCEEALCNNLSVE 122

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 17531579 186 PSDVTKDLENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYtGT 265
Cdd:cd18286   1 CSRLGKDLLQLFLNGEDSDITIKVDGKTFKAHRCILCARSSYFAAMLSGSWAESNSSEITLTGVSHAAVSFVLLFIY-GG 79

                        90       100       110
                ....*....|....*....|....*....|....
gi 17531579 266 CTNMGGNA--LDILAAAERFALPGLKNIAEVAMR 297
Cdd:cd18286  80 VLDLPDDVnlGELLSLADMYGLDGLKDVVAYTLR 113

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 17531579 189 VTKDLENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTN 268
Cdd:cd18342   9 LADELGGLWENSRFTDCCLCVAGQEFQAHKAILAARSPVFSAMFEHEMEESKKNRVEINDVEPEVFKEMMCFIYTGKAPN 88

                        90       100       110
                ....*....|....*....|....*....|....*
gi 17531579 269 MGGNALDILAAAERFALPGLKNIAEVAMRNGLATE 303
Cdd:cd18342  89 LDKMADDLLAAADKYALERLKVMCEDALCSNLSVE 123

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 17531579 187 SDVTKDLENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGtC 266
Cdd:cd18287   7 HFLSEDIGALFLNEEYSDVTFVVEEKRFPAHRVILAARSEYFRALLYGGMRESQQSEIELKDTNAEAFKALLKYIYTG-R 85

                        90       100
                ....*....|....*....|....*...
gi 17531579 267 TNMGG----NALDILAAAERFALPGLKN 290
Cdd:cd18287  86 LTLTDlkedVLLDVLGLAHQYGFEELEA 113

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 17531579 191 KDLENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTNMG 270
Cdd:cd18280   3 QHFGALLESEEGADVTFNVDGEKFRAHKLVLAARSPVFRSMLFGPMREENEGEIVIEDVEPPVFKALLHFIYKDELPDDV 82

                        90       100       110
                ....*....|....*....|....*....|....*.
gi 17531579 271 GNA------LD------ILAAAERFALPGLKNIAEV 294
Cdd:cd18280  83 EPAgsdsssLDttmaqhLLAAADRYALERLRLLCES 118

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Kelch-like protein 7 (KLHL7); KLHL7 is a component of a Cul3-based E3 ubiquitin ligase complex and is involved in the ubiquitination of target proteins for proteasome-mediated degradation. Mutations in KLHL7 causes autosomal-dominant retinitis pigmentosa. 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 17531579 186 PSDVTKDLENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGT 265
Cdd:cd18237   5 LADFMGVMNNMRKQKTLCDVILIVEGREIKAHRVVLAAASHFFHLMFTSNMTESKSSEVELKDAEPDIIELLVEFAYTAR 84

                        90       100
                ....*....|....*....|....*
gi 17531579 266 CTNMGGNALDILAAAERFALPGLKN 290
Cdd:cd18237  85 ISVNSNNVQSLLDAANQYQIEPVKK 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 17531579 185 MPSDVTKDLENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTG 264
Cdd:cd18247   2 LPSSGFPVMEEIRRQGKLCDVTLKVGDQKFSAHRIVLAATIPYFHAMFTHDMVESKQDEITMQGIEPSALEALINFAYSG 81

                        90       100
                ....*....|....*....|....*
gi 17531579 265 TCTNMGGNALDILAAAERFALPGLK 289
Cdd:cd18247  82 RIAIDTSNVQSLLVGASFLQLQSVK 106

BTB (Broad-Complex, Tramtrack and Bric a brac) /POZ (poxvirus and zinc finger) domain found in plant ARM repeat protein interacting with ABF2 (ARIA) and similar proteins; ARIA is an armadillo (ARM) repeat and BTB domain-containing protein that acts as a positive regulator of ABA response via the modulation of the transcriptional activity of ABF2, a transcription factor which controls ABA-dependent gene expression via the G-box-type ABA-responsive elements. ARIA is a novel abscisic acid signaling component. It negatively regulates seed germination and young seedling growth. 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 17531579 203 ADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTNMGGNALDILAAAER 282
Cdd:cd18352  14 SDVTFLVEGRRFYAHRIALLASSDAFRAMFDGGYREKEARDIEIPNIRWEVFELMMRFIYTGSVDITNDIAKDLLRAADQ 93

                        90       100
                ....*....|....*....|...
gi 17531579 283 FALPGLKNIAEVAMRNGLATETV 305
Cdd:cd18352  94 YLLEGLKRLCEYTIAQDLTLENI 116

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Kelch-like proteins, KLHL40 and KLHL41; This family includes Kelch-like proteins, KLHL40 and KLHL41. KLHL40 is a substrate-specific adaptor of a BCR (BTB-CUL3-RBX1) E3 ubiquitin ligase complex that acts as a key regulator of skeletal muscle development. KLHL41 is a novel kelch related protein that is involved in pseudopod elongation in transformed cells. They both contain 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 17531579 193 LENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTNMGGN 272
Cdd:cd18269  18 LKDLLDENKFVDCVLKIGDKEFPCHRLVLAACSPYFRAMFLSDLEESKKKEVVLEDVDPDVMGMILKYLYTSEIDLNDQN 97

                        90
                ....*....|....
gi 17531579 273 ALDILAAAERFALP 286
Cdd:cd18269  98 VQDIFALASRFQIP 111

MATH (meprin and TRAF-C homology) domain; an independent folding unit with an eight-stranded beta-sandwich structure found in meprins, TRAFs and other proteins. Meprins comprise a class of extracellular metalloproteases which are anchored to the membrane and are capable of cleaving growth factors, extracellular matrix proteins, and biologically active peptides. TRAF molecules serve as adapter proteins that link cell surface receptors of the Tumor Necrosis Factor and 1nterleukin-1/Toll-like families to downstream kinase cascades, which results in the activation of transcription factors and the regulation of cell survival, proliferation and stress responses in the immune and inflammatory systems. Other members include the ubiquitin ligases, TRIM37 and SPOP, and the ubiquitin-specific proteases, HAUSP and Ubp21p. A large number of uncharacterized members mostly from lineage-specific expansions in C. elegans and rice contain MATH and BTB domains, similar to SPOP. The MATH domain has been shown to bind peptide/protein substrates in TRAFs and HAUSP. It is possible that the MATH domain in other members of this superfamily also interacts with various protein substrates. The TRAF domain may also be involved in the trimerization of TRAFs. Based on homology, it is postulated that the MATH domain in meprins may be involved in its tetramer assembly and that the MATH domain, in general, may take part in diverse modular arrangements defined by adjacent multimerization domains.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17531579  26 KHMWTIRGFSQLECRYLETSAKikditvplthqpsSSGGlpelpdITFRIRLHPQGNKESNKDFTFFQCFTNQATTTTTP 105
Cdd:cd00121   2 KHTWKIVNFSELEGESIYSPPF-------------EVGG------YKWRIRIYPNGDGESGDYLSLYLELDKGESDLEKW 62

                        90       100       110       120       130       140
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 17531579 106 TFRAKFKFTVFNQRTEETPT-----TVYSGTQQLHGYFEYIRREVLVGHVQPADDlilCLTITITFD 167
Cdd:cd00121  63 SVRAEFTLKLVNQNGGKSLSksfthVFFSEKGSGWGFPKFISWDDLEDSYYLVDD---SLTIEVEVK 126

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        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17531579 192 DLENLYRSGKH--ADFTLVVEE-RELKAHKAILAARSPVF------AAMMEPHTAEAQNSRAILRD--IDYEVVQAILYY 260
Cdd:cd18310   6 DLENLLDSPDLfySDAEIIVEGgRPVPVHRCILAARSPFFrdifasAKAEGANTKPKLELRELIPGgiVGYDAFMLVLSY 85

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|...
gi 17531579 261 IYTG--------------------TCTNMGGNALDILAAAERFALPGLKNIAE 293
Cdd:cd18310  86 LYSGrlrlvpkegsacvdsdcwhvACRPAVDFALEVLYAASVFQIPELVSLFQ 138

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 17531579 204 DFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRA--ILRDIDYEVVQAILYYIYTGTCTNMGGNALDILAAAE 281
Cdd:cd18245  16 DATLVVGGEEIPVQKNVLAAASPYFRAKLNYNPPKDDGSTYkiELEGISVEVMEEILDYIYTGQIKLSEDNIQDIVQAAD 95

                        90
                ....*....|
gi 17531579 282 RFALPGLKNI 291
Cdd:cd18245  96 LLLMTDLKDL 105

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 17531579 191 KDLENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTNMG 270
Cdd:cd18250  10 RGLSELRAERKFFDVTLCAGGREFPCHRTVLAAASSYFRAMFAGELRESRADRVVLHGVSAEILGLLLDFSYTGRVTVTQ 89

                        90
                ....*....|....*....
gi 17531579 271 GNALDILAAAERFALPGLK 289
Cdd:cd18250  90 DNVEALLRAADLFQFPSVK 108

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 17531579 204 DFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTNMGGNALDILAAAERF 283
Cdd:cd18256  22 DVQLQVGMELFSVHRLVLAASSPYFAALFAGGMSESSKDVVQIHGVEPDIFHILLDFIYTGVVEVTVSNVQELLVAADML 101

                ....*...
gi 17531579 284 ALPGLKNI 291
Cdd:cd18256 102 QLTEVVEI 109

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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 17531579 193 LENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEphtAEAQNSRAI-LRD--IDYEVVQAILYYIYTG 264
Cdd:cd18295  10 LRRLLEQGSYSDVTFNVHGESFPAHRCILSARSPYFAEMFE---TKWKDKREInLKHplVNPDAFRALLQYLYTG 81

second BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in inhibitor of Bruton tyrosine kinase (IBtk); IBtk is an inhibitor or negative regulator of Bruton tyrosine kinase (Btk), which is required for B-cell differentiation and development. IBtk binds to the PH domain of Btk and down-regulates the Btk kinase activity. It contains two BTB domains. 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 17531579 192 DLENLYrsgkhaDFTLVVEE-RELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTNMG 270
Cdd:cd18302   1 KHSDLY------DVTIVSEDgKEFPCHKCVLVARLEYFHSMLSSSWIEASSCSALTMPIPSDILEIILDYLYTDEASAVK 74

                        90       100       110
                ....*....|....*....|....*....|.
gi 17531579 271 GNAL-----DILAAAERFALPGLKNIAEVAM 296
Cdd:cd18302  75 ESQNveflcNVLVIADQLLITRLKEICEVAL 105

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 17531579 193 LENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTNMGGN 272
Cdd:cd18341  18 LKELLDENKFVDCTLKAGDKSLPCHRLILAACSPYFREYFLSEESEEKKKEVVLDNVDPNIMDMILKYLYSAEIDLNDGN 97

                        90
                ....*....|....
gi 17531579 273 ALDILAAAERFALP 286
Cdd:cd18341  98 VQDIFALASRFQIP 111

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Kelch-like protein 17 (KLHL17); KLHL17, also called actinfilin, is a substrate-recognition component of some cullin-RING-based BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complexes. It acts as a Cullin 3 (Cul3) substrate adaptor that links GLUR6 to the E3 ubiquitin-ligase complex, and mediates the ubiquitination and subsequent degradation of GLUR6. It may play a role in actin-based neuronal function. 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 17531579 193 LENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTNMGGN 272
Cdd:cd18246  30 MNRMRQRGLLCDIVLHVGTKEIKAHKVVLASCSPYFHAMFTNEMSESRQTHVTLHDIDPQALEQLVQYAYTAEIVVGEGN 109

                        90
                ....*....|....*...
gi 17531579 273 ALDILAAAERFALPGLKN 290
Cdd:cd18246 110 VQTLLPAASLLQLNGVRD 127

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Kelch-like protein 28 (KLHL28); KLHL28, also called BTB/POZ domain-containing protein 5 (BTBD5), 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 17531579 189 VTKDLENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTN 268
Cdd:cd18257   5 LLQGLNLLRQHHELCDVVLRVGDVKIHAHKVVLASCSPYFKAMFTGNLSEKENSEVEFQCIDETALQAIVEYAYTGTVFI 84

                        90
                ....*....|....*..
gi 17531579 269 MGGNALDILAAAERFAL 285
Cdd:cd18257  85 SQATVESLLPAANLLQI 101

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Kelch-like proteins, KLHL2 and KLHL3; The family includes Kelch-like proteins, KLHL2 and KLHL3. KLHL2 is a novel actin-binding protein predominantly expressed in brain. It plays a role in the reorganization of the actin cytoskeleton, and promotes growth of cell projections in oligodendrocyte precursors. KLHL2 and KLHL3 each functions as a component of an E3 ubiquitin ligase complex that mediates the ubiquitination of target proteins. They contain a BTB domain and kelch repeat domains, 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 17531579 204 DFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTNMGGNALDILAAAERF 283
Cdd:cd18235  23 DVILVADGVEIPAHRVVLASCSPYFHAMFTGDLSESRANRVTLQDVDGKALLLLIDYVYTAEIQVTEENVQVLLPAANLL 102

                ....*..
gi 17531579 284 ALPGLKN 290
Cdd:cd18235 103 QLTDVRD 109

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Kelch-like protein 20 (KLHL20); KLHL20, also called Kelch-like ECT2-interacting protein (KLEIP) or Kelch-like protein X, is a substrate-specific adaptor of a BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex involved in interferon response and anterograde Golgi to endosome transport. KLHL20 plays a role in actin assembly at cell-cell contact sites of Madin-Darby canine kidney cells. It also controls endothelial migration and sprouting angiogenesis. 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 17531579 186 PSDVTKDLENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGT 265
Cdd:cd18249   7 PRQTLEAINLLRKHRELCDVVLVVGAKKIYAHRVILSACSPYFRAMFTGELAESRQTEVTIRDIDERAMELLIDFAYTSQ 86

                        90
                ....*....|....*
gi 17531579 266 CTNMGGNALDILAAA 280
Cdd:cd18249  87 ITVEEGNVQTLLPAA 101

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 17531579 205 FTLVVEERELKAHKAILAARSPVFAAMMEPHTAEAQNSRAILRDIDYEVVQAILYYIYTGTCTNMGGNALDILAAAERF 283
Cdd:cd01165   1 VVLVVEGEKFHVNKELLAQSSEYFRALFRGGFRESGQAEINLRDISPEDFRALLEFLYGGKRDLDASNLLELLEAANFL 79

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in zinc finger and BTB domain-containing protein 24 (ZBTB24); ZBTB24, also called zinc finger protein 450, functions as a transcription factor essentially involved in B-cell functions in humans. The loss-of-function mutations in ZBTB24 can cause ICF2 (immunodeficiency, centromeric instability and facial anomalies syndrome 2) with immunological characteristics of greatly reduced serum antibodies and circulating memory B cells. ZBTB24 contains a BTB/POZ domain, a common protein-protein interaction motif of about 100 amino acids.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17531579 187 SDVTKD-----LENLYRSGKHADFTLVVEERELKAHKAILAARSPVFAAMMephTAEAQNSRAI--LRDIDYEVVQAILY 259
Cdd:cd18212   3 SKTHKDtvltnFEEQRKKDFLCDITLIVENVQFRAHKALLAASSEYFSMMF---ADEGEVGQSIymLEGMVAETFGALLE 79