BTB/POZ domain; In voltage-gated K+ channels this domain is responsible for subfamily-specific assembly of alpha-subunits into functional tetrameric channels. In KCTD1 this domain functions as a transcriptional repressor. It also mediates homomultimerization of KCTD1 and interaction of KCTD1 with the transcription factor AP-2-alpha.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269    20 VELNVGGQFYTTTMGTLMKHPGSKFSEILSRSARHYKDAQGRFFIDRPGTYFGLLLDYLRTG---QVPTEY-VPEVYQEA 95
Cdd:pfam02214   1 VKLNVGGTRFETLKSTLTRFPDTRLGRLLELECDDYDDDTNEYFFDRSPKHFETILNFYRTGgklHRPEEVcLDEFLEEA 80

                  ....*
gi 74208269    96 KFYQI 100
Cdd:pfam02214  81 EFYGL 85

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing protein 7 (KCTD7); KCTD7 is a BTB/POZ domain-containing protein that has an impact on K+ fluxes, neurotransmitter synthesis, and neuronal function. It functions as a regulator of potassium conductance in neurons, and is involved in the control of excitability of cortical neurons. Mutations in KCTD7 may cause progressive myoclonus epilepsy (PME). The BTB/POZ domain, also known as tetramerization (T1) domain, is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  19 VVELNVGGQFYTTTMGTLMKHPGSKFSEILSrsARHY--KDAQGRFFIDRPGTYFGLLLDYLRTGQVP-TEYVPEVYQEA 95
Cdd:cd18366   5 VVPLNVGGMHFTTRLSTLRKYEDSMLAAMFS--GRHHipKDSEGRYFIDRDGSYFGYILNFLRDGDLPpRERARAVYKEA 82

                ....*....
gi 74208269  96 KFYQIHLLV 104
Cdd:cd18366  83 QYYGIGPLI 91

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing proteins; The potassium channel tetramerization domain (KCTD) family proteins contain the BTB/POZ domain, also known as tetramerization (T1) domain, which is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD proteins play crucial roles in a variety of fundamental biological processes, such as protein ubiquitination and degradation, suppression of proliferation or transcription, cytoskeleton regulation, tetramerization and gating of ion channels and others. Some KCTD proteins are involved in protein ubiquitination as part of the CRL (Cullin RING Ligase) E3 ligases. Some others show Cullin-independent functions including binding and regulation of GABA (gamma-aminobutyric acid) receptors (KCTD8, KCTD12 and KCTD16) and inhibition of AP-2 function (KCTD15). KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  20 VELNVGGQFYTTTMGTLMKHPGSKFSEILSRSARHYKDAQGRFFIDRPGTYFGLLLDYLRTGQV--PTEYV--PEVYQEA 95
Cdd:cd18316   1 VKLNVGGTLFTTSRSTLLKDPDSLLAALFSGRWPLPRDEDGSIFIDRDPELFRHILNFLRTGKLplPSDFVelEELLAEA 80

                ...
gi 74208269  96 KFY 98
Cdd:cd18316  81 EFY 83

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel regulatory protein (KCNRG); KCNRG, also called potassium channel regulator or protein CLLD4, is an endoplasmic reticulum (ER)-associated tumor suppressor that regulates Kv1 family potassium channel proteins by retaining a fraction of the channels in endomembranes. It contains a BTB/POZ domain, also known as tetramerization (T1) domain, which is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  19 VVELNVGGQFYTTTMGTLMKHPGSKFSEILSRSARHYKDAQGRFFIDRPGTYFGLLLDYLRTGQV--PTEY--VPEVYQE 94
Cdd:cd18375   2 LVTLNVGGKKFTTRPSTLRRFPDSRLARMLDGKDQDFKVVNGQFFVDRDGSLFSYILDYLRTGQLtlPTEFsdYNRLARE 81

                        90
                ....*....|....
gi 74208269  95 AKFYQIHLLVKILE 108
Cdd:cd18375  82 AEFYGLYSLADLLS 95

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing proteins, KCTD6, KCTD21 and similar proteins; KCTD6, also called KCASH3 (KCTD containing, Cullin3 adaptor, suppressor of Hedgehog 3), is a substrate-specific adaptor of cullin-3, effectively regulating protein levels of the muscle small ankyrin-1 isoform 5 (sAnk1.5). KCTD21, also called KCASH2, functions as a substrate-specific adaptor of cullin-3, promoting the ubiquitination and degradation of histone deacetylase HDAC1, thereby inhibiting the deacetylation-mediated transcriptional activation of the Hedgehog effectors Gli1 and Gli2. The BTB/POZ domain, also known as tetramerization (T1) domain, is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  19 VVELNVGGQFYTTTMGTLMKHPGSKFSEILSRSARHYKDAQGRFFIDRPGTYFGLLLDYLRTGQ--VPTEY--VPEVYQE 94
Cdd:cd18365   2 IVNLNVGGVHYTTTLATLTRFPDSMLGAMFSGSMPTTRDDQGNYFIDRDGTLFRYILNFLRSSQlsLPEDFkeYDLLLRE 81

                        90
                ....*....|...
gi 74208269  95 AKFYQIHLLVKIL 107
Cdd:cd18365  82 ADFYQIEPLIEAL 94

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing protein 21 (KCTD21); KCTD21, also calledz KCTD containing, Cullin3 adaptor, suppressor of Hedgehog 2 (KCASH2), is a BTB/POZ domain-containing protein that functions as a substrate-specific adaptor of cullin-3, promoting the ubiquitination and degradation of histone deacetylase HDAC1, thereby inhibiting the deacetylation-mediated transcriptional activation of the Hedgehog effectors Gli1 and Gli2. The BTB/POZ domain, also known as tetramerization (T1) domain, is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  20 VELNVGGQFYTTTMGTLMKHPGSKFSEILSRSARHYKDAQGRFFIDRPGTYFGLLLDYLRTGQVPteyVPEVYQ------ 93
Cdd:cd18395   3 ITLNVGGKLYTTSLATLTRYPDSMLGAMFSGKFPTKKDSQGNCFIDRDGKIFRYILNFLRTSHLD---LPEDFQemgllk 79

                        90
                ....*....|....*..
gi 74208269  94 -EAKFYQIHLLVKILED 109
Cdd:cd18395  80 rEADFYQIQPLIEALQE 96

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing protein 6 (KCTD6); KCTD6, also called KCTD containing, Cullin3 adaptor, suppressor of Hedgehog 3 (KCASH3), is a BTB/POZ domain-containing protein that functions as a substrate-specific adaptor of cullin-3, regulating protein levels of the muscle small ankyrin-1 isoform 5 (sAnk1.5) as well as suppressing histone deacetylase and Hedgehog activity in medulloblastoma. The BTB/POZ domain, also known as tetramerization (T1) domain, is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  20 VELNVGGQFYTTTMGTLMKHPGSKFSEILSRSARHYKDAQGRFFIDRPGTYFGLLLDYLRTGQ--VPTEY--VPEVYQEA 95
Cdd:cd18394   5 VTLNVGGHLYTTSLSTLTRYPDSMLGAMFRGDFPTARDSQGNYFIDRDGPLFRYILNFLRTSEltLPVDFkeFDLLRKEA 84

                        90
                ....*....|....
gi 74208269  96 KFYQIHLLVKILED 109
Cdd:cd18394  85 DFYQIEPLIQCLND 98

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing proteins, KCTD10 (BACURD3), KCTD13 (BACURD1), and TNFAIP1 (BACURD2); This subfamily of KCTD proteins, also called the BTB/POZ domain-containing adapter for CUL3-mediated RhoA degradation protein (BACURD) subfamily, includes KCTD10 (BACURD3), KCTD13 (BACURD1), and TNFAIP1 (BACURD2). KCTD10 is a BTB/POZ domain-containing protein that interacts with proliferating cell nuclear antigen (PCNA) and polymerase delta, and participates in DNA repair, DNA replication, and cell-cycle control. Its down-regulation could inhibit cell proliferation. KCTD10 also plays crucial roles in embryonic angiogenesis and heart development in mammals by negatively regulating the Notch signaling pathway. KCTD13 is a BTB/POZ domain-containing protein that may function as a substrate-specific adaptor of a BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex that mediates the ubiquitination of RhoA, leading to its degradation by the proteasome, thereby regulating the actin cytoskeleton and cell migration. TNFAIP1, also called protein B12, is a BTB/POZ domain-containing protein that is involved in DNA replication, DNA damage repair, cell apoptosis, and is implicated in human diseases including cancer, Alzheimer's disease (AD) and type 2 diabetic nephropathy. The BTB/POZ domain, also known as tetramerization (T1) domain, is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization. KCTD10 and KCTD13 BTB domains form a novel two-fold symmetric tetramer that is distinct from the tetramer formed by voltage-gated potassium (Kv) channels.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  20 VELNVGGQFYTTTMGTLMKHpGSKFSEILSRSARHYKDAQGRFFIDRPGTYFGLLLDYLRTGQVP----TEYVPEVYQEA 95
Cdd:cd18369   1 VKLNVGGSLHYTTIGTLTKQ-DTMLRAMFSGRMEVLTDSEGWILIDRCGKHFGTILNYLRDGSVPlpesRRELAELLAEA 79

                        90
                ....*....|.
gi 74208269  96 KFYQIHLLVKI 106
Cdd:cd18369  80 KYYLVQGLVEQ 90

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing proteins, KCTD1 and KCTD15; This subfamily of KCTD proteins includes KCTD1 and KCTD15. KCTD1 is a nuclear BTB/POZ domain-containing protein that acts as a transcriptional repressor and mediates protein-protein interactions through a BTB domain. It represses the transcriptional activity of AP-2 family members, including TFAP2A, TFAP2B and TFAP2C. It also functions as a novel inhibitor of the Wnt signaling pathway. Mutations in KCTD1 cause scalp-ear-nipple (SEN) syndrome. KCTD15 is a BTB/POZ domain-containing protein that plays a role in the regulation of neural crest (NC) formation and other steps in embryonic development. It inhibits AP2 transcriptional activity by interaction with its activation domain. The BTB/POZ domain, also known as tetramerization (T1) domain, is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization. The KCTD1 BTB domains form pentamers.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  20 VELNVGGQFYTTTMGTLMKHPGSKFSE--------ILSRSARHYkdaqgrfFIDRPGTYFGLLLDYLRTGQV--PTEY-- 87
Cdd:cd18361   1 VHIDVGGHIYTSSLETLTKYPESRLGKlfngsipiVLDSLKQHY-------FIDRDGKMFRHILNFLRTSKLllPDDFte 73

                        90       100
                ....*....|....*....|.
gi 74208269  88 VPEVYQEAKFYQIHLLVKILE 108
Cdd:cd18361  74 FDLLYEEARYYELQPMVKQLE 94

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing protein 13 (KCTD13); KCTD13, also called BTB/POZ domain-containing adapter for CUL3-mediated RhoA degradation protein 1 (BACURD1), or TNFAIP1-like protein, is a BTB/POZ domain-containing protein that may function as a substrate-specific adaptor of a BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex that mediates the ubiquitination of RhoA, leading to its degradation by the proteasome, thereby regulating the actin cytoskeleton and cell migration. The BTB/POZ domain, also known as tetramerization (T1) domain, is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization. The KCTD13 BTB domain forms a novel two-fold symmetric tetramer that is distinct from the tetramer formed by voltage-gated potassium (Kv) channels.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  17 AKVVELNVGGQFYTTTMGTLMKHpGSKFSEILSRSARHYKDAQGRFFIDRPGTYFGLLLDYLRTGQVP----TEYVPEVY 92
Cdd:cd18400   1 SKYVKLNVGGSLHYTTVQTLTKQ-DTMLKAMFSGRVEVLTDSEGWVLIDRSGRHFGTILNYLRDGSVPlpesTRELEELL 79

                        90
                ....*....|...
gi 74208269  93 QEAKFYQIHLLVK 105
Cdd:cd18400  80 GEARYYLVQGLVE 92

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in SH3KBP1-binding protein 1 (SHKBP1); SHKBP1, also called SETA-binding protein 1, interacts with cathepsin B and participates in tumor necrosis factor (TNF)-induced apoptosis in ovarian cancer cells. It can promote epidermal growth factor receptor (EGFR) signaling by interrupting c-Cbl-CIN85 complex and inhibiting EGFR degradation. It contains a BTB/POZ domain, also known as tetramerization (T1) domain, a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  17 AKVVELNVGGQFYTTTMGTLMKHPGSKFSEILSRSARHYKDAQGRFFIDRPGTYFGLLLDYLRTGQVPTE--YVPEVYQE 94
Cdd:cd18393   1 GEVIHLNVGGKRFSTSRQTLTWIPDSFFSSLLSGRISTLKDETGAIFIDRDPTVFAPILNFLRTKELDPRgiHVSLLLHE 80

                        90
                ....*....|....
gi 74208269  95 AKFYQIHLLVKILE 108
Cdd:cd18393  81 AQFYGITPLVRRLQ 94

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing proteins KCTD2, KCTD5, and KCTD17, and similar proteins; This subfamily includes potassium channel tetramerization domain-containing proteins KCTD2, KCTD5, and KCTD17, all of which function as adaptors of Cullin3 based ubiquitin E3 ubiquitin ligases. KCTD2 suppresses gliomagenesis by destabilizing c-Myc. KCTD5 is a negative regulator of the AKT pathway, a key signaling cascade frequently deregulated in cancer. KCTD5 does not impact the operation of Kv4.2, Kv3.4, Kv2.1, or Kv1.2 channels. KCTD17 polyubiquitylates trichoplein, a protein involved in ciliogenesis down-regulation. It is a positive regulator of ciliogenesis, playing a crucial role in the initial steps of axoneme extension. A missense mutation in KCTD17 causes autosomal dominant myoclonus-dystonia (M-D). The BTB/POZ domain, also known as tetramerization (T1) domain, is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization. KCTD5 and KCTD17 BTB domains form pentamer structures.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  20 VELNVGGQFYTTTMGTLMKHPGSKFSEILSRSAR--HYKDAQGRFFIDRPGTYFGLLLDYLRTGQ-VPTEYVPE--VYQE 94
Cdd:cd18362   2 VKLNVGGTYFLTTRTTLCRDPKSFLCRLCQEDPDlpSDKDETGAYLIDRDPTYFGPILNYLRHGKlIIDKDLAEegVLEE 81

                ....
gi 74208269  95 AKFY 98
Cdd:cd18362  82 AEFY 85

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 74208269     20 VELNVGGQFYTTTMGTLMKHPgSKFSEILSrSARHYKDAQGRFFIDRPGTYFGLLLDYLRTGQV--PTEYVPEVYQEAKF 97
Cdd:smart00225   2 VTLVVGGKKFHAHKAVLAAHS-PYFKALFS-SDFKESDKSEIYLDDVSPEDFRALLNFLYTGKLdlPEENVEELLELADY 79

                           90
                   ....*....|...
gi 74208269     98 YQIHLLVKILEDM 110
Cdd:smart00225  80 LQIPGLVELCEEF 92

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing protein KCTD11; KCTD11 may function as an antagonist of the Hedgehog pathway of cell proliferation and differentiation by affecting the nuclear transfer of transcription factor GLI1, thus maintaining cerebellar granule cells in the undifferentiated state. It is a probable substrate-specific adapter for a BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex towards HDAC1. It contains a BTB/POZ domain; in some cases the domain may be truncated. The BTB/POZ domain, also known as tetramerization (T1) domain, is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization. Variants of the human/mouse KCTD11 appear to contain truncated BTB/POZ domains.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  20 VELNVGGQFYTTTMGTLMKHPGSKFSEILSRSAR----HYKDAQGRFFIDRPGTYFGLLLDYLRTGQVPteyVPEVY--- 92
Cdd:cd18370   1 VTLNVGGTLYSTTLETLTRFPDSMLGAMFRAGTPippnLNMQGGGHYFIDRDGKAFRHILNFLRLGRLD---LPRGYget 77

                        90
                ....*....|.
gi 74208269  93 ----QEAKFYQ 99
Cdd:cd18370  78 allrAEADFYQ 88

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing protein 3 (KCTD3); KCTD3, also called renal carcinoma antigen NY-REN-45, is a BTB/POZ domain-containing protein that is an accessory subunit of potassium/sodium hyperpolarization-activated cyclic nucleotide-gated channel 3 (HCN3), upregulating its cell-surface expression and current density without affecting its voltage dependence and kinetics. The BTB/POZ domain, also known as tetramerization (T1) domain, is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  19 VVELNVGGQFYTTTMGTLMKHPGSKFSEILSRSARHYKDAQGRFFIDRPGTYFGLLLDYLRTGQVPTEYV--PEVYQEAK 96
Cdd:cd18392   3 IIQLNVGGTRFSTSRQTLMWIPDSFFSSLLSGRISSLKDETGAIFIDRDPTAFVPILNFLRTKELDLRGVniNVLRHEAE 82

                ....
gi 74208269  97 FYQI 100
Cdd:cd18392  83 FYGI 86

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in tumor necrosis factor, alpha-induced protein 1, endothelial (TNFAIP1); TNFAIP1, also called BTB/POZ domain-containing adapter for CUL3-mediated RhoA degradation protein 2 (BACURD2), or protein B12, is a BTB/POZ domain-containing protein that is involved in DNA replication, DNA damage repair and cell apoptosis, and is implicated in human diseases including cancer, Alzheimer's disease (AD) and type 2 diabetic nephropathy. The BTB/POZ domain, also known as tetramerization (T1) domain, is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization. The BTB domains of other BACURD subfamily members, KCTD10 and KCTD13, form a novel two-fold symmetric tetramer that is distinct from the tetramer formed by voltage-gated potassium (Kv) channels.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  18 KVVELNVGGQFYTTTMGTLMKHpGSKFSEILSRSARHYKDAQGRFFIDRPGTYFGLLLDYLRTGQV----PTEYVPEVYQ 93
Cdd:cd18401   3 KYVRLNVGGSLYYTTVQVLTRH-DTMLKAMFSGRMEVLTDKEGWILIDRCGKHFGTILNYLRDDTValpkSRQEIKELMA 81

                        90
                ....*....|...
gi 74208269  94 EAKFYQIHLLVKI 106
Cdd:cd18401  82 EAKYYLIQGLVDM 94

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing protein 1 (KCTD1); KCTD1 is a nuclear BTB/POZ domain-containing protein that acts as a transcriptional repressor and mediates protein-protein interactions through a BTB domain. It represses the transcriptional activity of AP-2 family members, including TFAP2A, TFAP2B and TFAP2C to various extent. It also functions as a novel inhibitor of the Wnt signaling pathway. Mutations in KCTD1 cause scalp-ear-nipple (SEN) syndrome. The BTB/POZ domain, also known as tetramerization (T1) domain, is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization. The KCTD1 BTB domains form pentamers.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  20 VELNVGGQFYTTTMGTLMKHPGSKFSEILSRSARHYKDA-QGRFFIDRPGTYFGLLLDYLRTGQ--VPTEY--VPEVYQE 94
Cdd:cd18387   5 VHIDVGGHMYTSSLATLTKYPESRIGRLFDGTEPIVLDSlKQHYFIDRDGQMFRYILNFLRTSKllIPDDFkdYSLLYEE 84

                        90
                ....*....|....
gi 74208269  95 AKFYQIHLLVKILE 108
Cdd:cd18387  85 AKYFQLQPMLLELE 98

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium voltage-gated channel protein Shaw; Shaw, also called Shaw2, is a voltage-gated potassium channel in Drosophila. It mediates transmembrane potassium transport in excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a tetrameric potassium-selective channel through which potassium ions may pass in accordance with their electrochemical gradient. Voltage-gated potassium (Kv) channels are composed of alpha subunits, which form the actual conductance pore, and cytoplasmic beta subunits, which are auxiliary proteins that associate with alpha subunits to modulate the activity of the Kv channel. Shaw is an alpha subunit that forms functional homo- or hetero-tetrameric channels (with other alpha subunits) through its BTB/POZ domain, also known as tetramerization (T1) domain, which is a versatile protein-protein interaction motif.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  16 DAKVVeLNVGGQFYTTTMGTLMKHPGSKFSEiLSRSARHYKDAQGRFFIDRPGTYFGLLLDYLRTGQV--PTEYVPEVYQ 93
Cdd:cd18416   1 ENRVV-LNVGGIRHETYKATLKKIPATRLSR-LTEALANYDPVLNEYFFDRHPGVFAQILNYYRTGKLhyPTDVCGPLFE 78

                .
gi 74208269  94 E 94
Cdd:cd18416  79 E 79

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium voltage-gated channel subfamily C members KCNC1 and KCNC3; KCNC1 (also called NGK2, voltage-gated potassium channel subunit Kv3.1, or voltage-gated potassium channel subunit Kv4) and KCNC3 (also called KSHIIID or voltage-gated potassium channel subunit Kv3.3) play important roles in the rapid repolarization of fast-firing brain neurons. Assuming opened or closed conformations in response to the voltage difference across the membrane, the proteins form tetrameric potassium-selective channels through which potassium ions may pass in accordance with their electrochemical gradient. Voltage-gated potassium (Kv) channels are composed of alpha subunits, which form the actual conductance pore, and cytoplasmic beta subunits, which are auxiliary proteins that associate with alpha subunits to modulate the activity of the Kv channel. KCNC1 and KCNC3 are alpha subunit that form functional homo- or hetero-tetrameric channels (with other alpha subunits) through their BTB/POZ domain, also known as tetramerization (T1) domain, which is a versatile protein-protein interaction motif.

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  16 DAKVVELNVGGQFYTTTMGTLMKHPGSKFSEILSRSARH---YKDAQGRFFIDRPGTYFGLLLDYLRTGQV--PTEYVPE 90
Cdd:cd18414   1 ESDRIVINVGGTRHETYRSTLRTLPGTRLAWLAEPDAHSnfdYDPRADEFFFDRHPGVFAHILNYYRTGKLhcPADVCGP 80

                ....
gi 74208269  91 VYQE 94
Cdd:cd18414  81 LYEE 84

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing protein 18 (KCTD18); KCTD18 is a BTB/POZ domain-containing protein with with unknown biological function. A duplication of the KCTD18 gene has been found in a patient with epilepsy, developmental delay, and autistic behavior, which may contribute to the phenotype. KCTD proteins play crucial roles in a variety of fundamental biological processes, such as protein ubiquitination and degradation, suppression of proliferation or transcription, cytoskeleton regulation, tetramerization and gating of ion channels and others. Some KCTD proteins are involved in protein ubiquitination as part of the CRL (Cullin RING Ligase) E3 ligases. The BTB/POZ domain, also known as tetramerization (T1) domain, is a versatile protein-protein interaction motif that facilitates homodimerization or heterodimerization. KCTD family BTB domains can adopt a wide range of oligomerization geometries, including homodimerization, tetramerization, and pentamerization.

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  19 VVELNVGGQFYTTTMGTLMKHPGSKFSEILSRSARHYKDAQGRFFIDRPGTYFGLLLDYLRtGQVpteYVPE-------V 91
Cdd:cd18372   2 VLRLNVGGCIYTARRESLCRFKDSMLSSMFSGRFPLKLDESGACVIDRDGRLFKYLLDYLH-GEL---QIPEdeqtrlaL 77

                ....*....
gi 74208269  92 YQEAKFYQI 100
Cdd:cd18372  78 QEEADYFGI 86

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium voltage-gated channel subfamily D member 2 (KCND2); KCND2, also called voltage-gated potassium channel subunit Kv4.2, is a major pore-forming subunit in somatodendritic subthreshold A-type potassium current I(SA) channels. It mediates transmembrane potassium transport in excitable membranes, primarily in the brain. Voltage-gated potassium (Kv) channels are composed of alpha subunits, which form the actual conductance pore, and cytoplasmic beta subunits, which are auxiliary proteins that associate with alpha subunits to modulate the activity of the Kv channel. KCND2 is an alpha subunit that forms functional homo- or hetero-tetrameric channels (with other Kv4/KCND alpha subunits) through its BTB/POZ domain, also known as tetramerization (T1) domain, which is a versatile protein-protein interaction motif. It is modulated by cytoplasmic KChIPs/KCNIPs (Kv-channel interacting proteins), which are small calcium binding proteins with EF-hand-like domains.

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 74208269  19 VVELNVGGQFYTTTMGTLMKHPGSkfseILSRSARH--YKDAQGRFFIDRPGTYFGLLLDYLRTGQV--PTEYVPEVY-Q 93
Cdd:cd18418   1 LIVLNVSGTRFQTWRNTLERYPDT----LLGSSERDffYHEETQEYFFDRDPDIFRHILNFYRTGKLhyPRHECISAYdE 76

                        90       100
                ....*....|....*....|...
gi 74208269  94 EAKFYQIhllvkiledMPQIFGE 116
Cdd:cd18418  77 ELAFFGI---------IPEIIGD 90

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in KCND/Kv4 subfamily of Shal-type voltage-dependent potassium channels; Voltage-gated potassium (Kv) channels are composed of alpha subunits, which form the actual conductance pore, and cytoplasmic beta subunits, which are auxiliary proteins that associate with alpha subunits to modulate the activity of the Kv channel. The potassium voltage-gated channel subfamily Kv4, also known as subfamily D, contains three alpha subunit members, Kv4.1 (KCND1), Kv4.2 (KCND2), and Kv4.3 (KCND3), which are orthologs of the Shal gene in Drosophila. They are A-type potassium channels that mediate the native, fast inactivating (A-type) K+ current (IA) described both in the nervous system (A currents) and the heart (transient outward current). Kv4/KCND subfamily alpha subunits form functional homo- or hetero-tetrameric channels through their BTB/POZ domain, also known as tetramerization (T1) domain, which is a versatile protein-protein interaction motif. They are modulated by cytoplasmic KChIPs/KCNIPs (Kv-channel interacting proteins), which are small calcium binding proteins with EF-hand-like domains.

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                ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 74208269  22 LNVGGQFYTTTMGTLMKHPgskfSEILSRSARH--YKDAQGRFFIDRPGTYFGLLLDYLRTGQ 82
Cdd:cd18380   4 INVSGRRFETWKNTLEKYP----DTLLGSTEKEffYDDDTKEYFFDRDPEIFRHILNFYRTGK 62