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 17567967   7 IRFNVGGTPMATLKTT---FPvDSIFHKWFVSRTkasPFTSDRDGAYFVDRDPFSFGVVLNYFRLRKagqlweACLPKDP 83
Cdd:cd18316   1 VKLNVGGTLFTTSRSTllkDP-DSLLAALFSGRW---PLPRDEDGSIFIDRDPELFRHILNFLRTGK------LPLPSDF 70

                        90
                ....*....|...
gi 17567967  84 DRLAMLTQEADFF 96
Cdd:cd18316  71 VELEELLAEAEFY 83

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 17567967   7 IRFNVGGTPMATLKTT---FPvDSIFHKWFVSRTkasPFTSDRDGAYFVDRDPFSFGVVLNYFRLRKagqlweACLPKDP 83
Cdd:cd18316   1 VKLNVGGTLFTTSRSTllkDP-DSLLAALFSGRW---PLPRDEDGSIFIDRDPELFRHILNFLRTGK------LPLPSDF 70

                        90
                ....*....|...
gi 17567967  84 DRLAMLTQEADFF 96
Cdd:cd18316  71 VELEELLAEAEFY 83

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 17567967      7 IRFNVGGTPMATLKTT---FPvdSIFHKWFVSRTKaspfTSDRDGAYFVDRDPFSFGVVLNYFRLRKagqlweacLPKDP 83
Cdd:smart00225   2 VTLVVGGKKFHAHKAVlaaHS--PYFKALFSSDFK----ESDKSEIYLDDVSPEDFRALLNFLYTGK--------LDLPE 67

                           90       100
                   ....*....|....*....|....*.
gi 17567967     84 DRLAMLTQEADFFLLPQLRDQAICML 109
Cdd:smart00225  68 ENVEELLELADYLQIPGLVELCEEFL 93

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 17567967   7 IRFNVGGTPMATLKTT---FPvDSIFHKWFVSRTkasPFTSDRDGAYFVDRDPFSFGVVLNYFRLRKagqlweACLPKDP 83
Cdd:cd18316   1 VKLNVGGTLFTTSRSTllkDP-DSLLAALFSGRW---PLPRDEDGSIFIDRDPELFRHILNFLRTGK------LPLPSDF 70

                        90
                ....*....|...
gi 17567967  84 DRLAMLTQEADFF 96
Cdd:cd18316  71 VELEELLAEAEFY 83

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in Arabidopsis thaliana FH protein interacting protein FIP2 and similar proteins; FIP2 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. 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 17567967   7 IRFNVGG----TPMATLkTTFPvDSIFHKWFVSRtkaSPFTSDRDGAYFVDRDPFSFGVVLNYFRlrkAGQLWEacLPKD 82
Cdd:cd18376   1 VKLNVGGqkftTTLDTL-TKDP-DSMLAAMFSGR---HSLKKDEDGSYFIDRDGTHFRHILNYLR---DGEVKI--PTED 70

                        90       100
                ....*....|....*....|..
gi 17567967  83 PDRLAMLTQEADFFllpQLRDQ 104
Cdd:cd18376  71 RSVLKELLEEAEYY---QLRGL 89

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 17567967   7 IRFNVGG----TPMATLkTTFPvDSIFHKWFVSRTKASPFT-SDRDGAYFVDRDPFSFGVVLNYFRLrkaGQLWeacLPK 81
Cdd:cd18370   1 VTLNVGGtlysTTLETL-TRFP-DSMLGAMFRAGTPIPPNLnMQGGGHYFIDRDGKAFRHILNFLRL---GRLD---LPR 72

                        90
                ....*....|....*
gi 17567967  82 DPDRLAMLTQEADFF 96
Cdd:cd18370  73 GYGETALLRAEADFY 87

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing proteins, KCTD8, KCTD12, KCTD16 and similar proteins; This subfamily of KCTD proteins includes KCTD8, KCTD12 (also called predominantly fetal expressed T1 domain/Pfetin), and KCTD16. They act as auxiliary subunits of GABAB receptors associated with mood disorders. KCTD8 interacts as a tetramer with GABRB1 and GABRB2. KCTD12 regulates agonist potency and kinetics of GABAB receptor signaling. It promotes tumorigenesis by facilitating CDC25B/CDK1/Aurora A-dependent G2/M transition. KCTD16 interacts with amyloid beta precursor protein (APP), a type I transmembrane protein involved in a variety of cellular processes such as cell adhesion, and axon guidance. 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 17567967   6 IIRFNVGG----TPMATLkTTFPvDSIFHKWFVSRTKASPfTSDRDGAYFVDRDPFSFGVVLNYFRLRKagqlweACLPK 81
Cdd:cd18367   4 IVELNVGGqvytTSLSTL-IKDP-DSLLGRMFSGKNRQEL-ARDSKGRYFLDRDGVLFRYILDYLRNQK------LVLPE 74

                        90       100
                ....*....|....*....|.
gi 17567967  82 D-PDRlAMLTQEADFFLLPQL 101
Cdd:cd18367  75 NfPER-ERLKREAEYFQLPEL 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 17567967   7 IRFNVGG----TPMATLkTTFPvDSIFHKWFVSRTkasPFTSDRDGAYFVDRDPFSFGVVLNYFRLRKAGqlweacLPKD 82
Cdd:cd18395   3 ITLNVGGklytTSLATL-TRYP-DSMLGAMFSGKF---PTKKDSQGNCFIDRDGKIFRYILNFLRTSHLD------LPED 71

                        90
                ....*....|....*....
gi 17567967  83 PDRLAMLTQEADFFLLPQL 101
Cdd:cd18395  72 FQEMGLLKREADFYQIQPL 90

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing protein 9 (KCTD9); KCTD9 is a BTB/POZ domain-containing protein that contributes to liver injury through NK cell activation during hepatitis B virus-induced acute-on-chronic liver failure. It functions as a substrate-specific adaptor of a BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex, which mediates the ubiquitination of target proteins, leading to their degradation by the proteasome. 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 KCTD9 BTB domain forms a pentameric structure.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17567967   7 IRFNVGG----TPMATLKTTFPvDSIFHKWFvSRTKASPFTSDRDGAYFVDRDPFSFGVVLNYFRlrkAGQLweaCLPKD 82
Cdd:cd18368   3 IKLNVGGriftTTRSTLVKKEP-DSMLARMF-SDDSTWPSSRDENGAYLIDRSPEYFEPILNYLR---HGQL---ILNDG 74

                        90       100
                ....*....|....*....|..
gi 17567967  83 PDRLAMLtQEADFFLLPQLRDQ 104
Cdd:cd18368  75 LNPLGVL-EEAKFFGIQSLIEI 95

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing protein 5 (KCTD5); KCTD5 is a BTB/POZ domain-containing protein that functions as a substrate adaptor for cullin3 based ubiquitin E3 ligases. It 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. 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 forms pentamers mediated by its BTB domain.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 17567967   7 IRFNVGGTPMATLKTTFPVDSifhKWFVSR-TKASP-FTSDRD--GAYFVDRDPFSFGVVLNYFR 67
Cdd:cd18390   7 VRLNVGGTYFLTTRQTLCRDP---KSFLYRlCQADPdLDSDKDetGAYLIDRDPTYFGPVLNYLR 68

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 17567967   7 IRFNVGG----TPMATLkTTFPvDSIFHKWFvsrTKASPFTSDRDGAYFVDRDPFSFGVVLNYFRLRkagqlwEACLPKD 82
Cdd:cd18394   5 VTLNVGGhlytTSLSTL-TRYP-DSMLGAMF---RGDFPTARDSQGNYFIDRDGPLFRYILNFLRTS------ELTLPVD 73

                        90
                ....*....|....*....
gi 17567967  83 PDRLAMLTQEADFFLLPQL 101
Cdd:cd18394  74 FKEFDLLRKEADFYQIEPL 92

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing protein 3 (KCTD3) and SH3KBP1-binding protein 1 (SHKBP1); The group of KCTD proteins includes KCTD3 and SHKBP1. 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. 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. 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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 17567967   6 IIRFNVGGTPMATLKTTF---PvDSIFHKWFVSRTkasPFTSDRDGAYFVDRDPFSFGVVLNYFRLR 69
Cdd:cd18363   3 IINLNVGGKRFSTSRQTLtwiP-DSFFTSLLSGRI---SSLKDETGAIFIDRDPKLFSIILNYLRTK 65

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 17567967   6 IIRFNVGGTPMATLKTTFP--VDSIFHKWFVSRTKAspfTSDRDGAYFVDRDPFSFGVVLNYFRLRKAgqlweaclpkDP 83
Cdd:cd18392   3 IIQLNVGGTRFSTSRQTLMwiPDSFFSSLLSGRISS---LKDETGAIFIDRDPTAFVPILNFLRTKEL----------DL 69

                        90
                ....*....|....*
gi 17567967  84 DRLAM--LTQEADFF 96
Cdd:cd18392  70 RGVNInvLRHEAEFY 84

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 17567967      7 IRFNVGGTPMATLKTT---FPvdSIFHKWFVSRTKaspfTSDRDGAYFVDRDPFSFGVVLNYFRLRKagqlweacLPKDP 83
Cdd:smart00225   2 VTLVVGGKKFHAHKAVlaaHS--PYFKALFSSDFK----ESDKSEIYLDDVSPEDFRALLNFLYTGK--------LDLPE 67

                           90       100
                   ....*....|....*....|....*.
gi 17567967     84 DRLAMLTQEADFFLLPQLRDQAICML 109
Cdd:smart00225  68 ENVEELLELADYLQIPGLVELCEEFL 93

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 17567967   6 IIRFNVGGTPMATLKTTFpvdsifHKWFVSRTKASPFTSDRD-----GAYFVDRDPFSFGVVLNYFRLRkagqlwEACLP 80
Cdd:cd18375   2 LVTLNVGGKKFTTRPSTL------RRFPDSRLARMLDGKDQDfkvvnGQFFVDRDGSLFSYILDYLRTG------QLTLP 69

                        90       100
                ....*....|....*....|...
gi 17567967  81 KDPDRLAMLTQEADFFLLPQLRD 103
Cdd:cd18375  70 TEFSDYNRLAREAEFYGLYSLAD 92

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 17567967   7 IRFNVGGT-PMATLKTTFPVDSIFHKWFVSRTKASpftSDRDGAYFVDRDPFSFGVVLNYFRlrkAGQLweaCLPKDPDR 85
Cdd:cd18400   4 VKLNVGGSlHYTTVQTLTKQDTMLKAMFSGRVEVL---TDSEGWVLIDRSGRHFGTILNYLR---DGSV---PLPESTRE 74

                        90       100
                ....*....|....*....|....*
gi 17567967  86 LAMLTQEADFFLLPQLRDQAICMLQ 110
Cdd:cd18400  75 LEELLGEARYYLVQGLVEDCQLALQ 99

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in KCNC/Kv3 subfamily of Shaw-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 Kv3, also known as subfamily C, contains four alpha subunit members, Kv3.1 (KCNC1), Kv3.2 (KCNC2), Kv3.3 (KCNC3), and Kv3.4 (KCNC4), which are orthologs of the Shaw gene in Drosophila. Unlike other Kv subfamilies, Kv3 channels typically open only at positive potentials and both, activation and deactivation, in response to changes in voltage are very rapid. They are uniquely associated with the ability of certain neurons to fire action potentials and to release neurotransmitter at high rates of up to 1,000 Hz. Kv3/KCNC subfamily alpha subunits 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.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 17567967   7 IRFNVGGTPMATLKTT---FPvDSIFHkWFVSRTKASPFTSDRDGAYFVDRDPFSFGVVLNYFRLRK 70
Cdd:cd18379   1 IVINVGGVRHETYKSTlrnLP-DTRLA-WLTETEASAFDYDPVTGEFFFDRHPGVFAQILNYYRTGK 65

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing protein 14 (KCTD14); KCTD14 is a BTB/POZ domain-containing protein with unknown biological function. 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.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 17567967   6 IIRFNVGG----TPMATLKTtFPvDSIFHKWFVSRTKASpftSDRDGAYFVDRDPFSFGVVLNYFR 67
Cdd:cd18371   3 VVSLNVGGhiytTTLSTLRK-FP-GSKLAELFNGQPKLR---TDSEGRYFIDRDGTYFRYILEYLR 63

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 17567967   7 IRFNVGGTPM-ATLKTTFPVDSIFHKWFVSRTKAspfTSDRDGAYFVDRDPFSFGVVLNYFRLRKAGqlweacLPKDPDR 85
Cdd:cd18401   5 VRLNVGGSLYyTTVQVLTRHDTMLKAMFSGRMEV---LTDKEGWILIDRCGKHFGTILNYLRDDTVA------LPKSRQE 75

                        90       100       110
                ....*....|....*....|....*....|.
gi 17567967  86 LAMLTQEADFFLLPQLRDqaICMLQLCSNKN 116
Cdd:cd18401  76 IKELMAEAKYYLIQGLVD--MCQAALQDKKD 104

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.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17567967   7 IRFNVGGTPMATLKTT---FPvDSifhkwFVSRTKASPFTSDRDGAYFVDRDPFSFGVVLNYFRlrkAGQLWeacLPKDp 83
Cdd:cd18380   2 IVINVSGRRFETWKNTlekYP-DT-----LLGSTEKEFFYDDDTKEYFFDRDPEIFRHILNFYR---TGKLH---YPRH- 68

                        90
                ....*....|....*..
gi 17567967  84 DRLAMLTQEADFFLLPQ 100
Cdd:cd18380  69 ECISAYDDELAFFGILP 85

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium voltage-gated channel subfamily D member 3 (KCND3); KCND3, also called voltage-gated potassium channel subunit Kv4.3, is a pore-forming subunit of voltage-gated rapidly inactivating A-type potassium channels. Mutations in KCND3 cause spinocerebellar ataxia. 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. KCND3 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.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17567967   6 IIRFNVGGTPMATLKTTFpvdSIFHKWFVSRTKASPFTSDRDGAYFVDRDPFSFGVVLNYFRLRKAGQLWEACLPKDPDR 85
Cdd:cd18419  36 LIVLNVSGRRFQTWRTTL---ERYPDTLLGSTEKEFFFNEDTKEYFFDRDPEVFRCVLNFYRTGKLHYPRYECISAYDEE 112

                        90
                ....*....|....*.
gi 17567967  86 LAMltqeadFFLLPQL 101
Cdd:cd18419 113 LAF------YGILPEI 122

BTB (Broad-Complex, Tramtrack and Bric a brac)/POZ (poxvirus and zinc finger) domain found in potassium channel tetramerization domain-containing protein 10 (KCTD10); KCTD10, also called BTB/POZ domain-containing adapter for CUL3-mediated RhoA degradation protein 3 (BACURD3), 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. Furthermore, KCTD10 may function as a substrate-specific adaptor of a BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex, which mediates the ubiquitination of target proteins, leading to their degradation by the proteasome. 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 KCTD10 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 17567967   7 IRFNVGGTPM-ATLKTTFPVDSIFHKWFVSRTKAspfTSDRDGAYFVDRDPFSFGVVLNYFRLRKAGqlweacLPKDPDR 85
Cdd:cd18399   9 VKLNVGGALYyTTMQTLTKQDTMLKAMFSGRMEV---LTDSEGWILIDRCGKHFGTILNYLRDGAVP------LPESRRE 79

                        90       100
                ....*....|....*....|....*
gi 17567967  86 LAMLTQEADFFLLPQLRDQAICMLQ 110
Cdd:cd18399  80 IEELLAEAKYYLVQGLVEECQAALQ 104