basic helix-loop-helix-Per-ARNT-Sim (bHLH-PAS) domain found in aryl hydrocarbon receptor nuclear translocator (ARNT) and similar proteins; ARNT, also termed Class E basic helix-loop-helix protein 2 (bHLHe2), or Dioxin receptor, nuclear translocator, or hypoxia-inducible factor 1-beta (HIF1b), or HIF-1-beta, or HIF1-beta, is a member of bHLH-PAS transcription regulators that acts as the heterodimeric partner for bHLH-PAS proteins such as aryl hydrocarbon receptor (AhR), hypoxia-inducible factor (HIF), and single-minded (SIM). These bHLH-PAS transcription complexes are involved in transcriptional responses to xenobiotic, hypoxia, and developmental pathways. Heterodimerization of bHLH-PAS proteins with ARNT is mediated by contacts between both the bHLH and the tandem PAS domains. ARNT use bHLH and/or PAS domains to interact with several transcriptional coactivators. It is required for activity of the aryl hydrocarbon (dioxin) receptor.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1176461133  85 KERLARENHSEIERRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMKSLRGTGNTST 149
Cdd:cd18947     1 KERFARENHSEIERRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMKSLRGTGNTST 65

PAS fold; The PAS fold corresponds to the structural domain that has previously been defined as PAS and PAC motifs. The PAS fold appears in archaea, eubacteria and eukarya. This domain can bind gases (O2, CO and NO), FAD, 4-hydroxycinnamic acid and NAD+ (Matilla et.al., FEMS Microbiology Reviews, fuab043, 45, 2021, 1. https://doi.org/10.1093/femsre/fuab043).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1176461133 162 ELKHLILEAADGFLFIVScETGRVVYVSDSVTPVLNQPQSEWFGSTLYDQVHPDD----VDKLREQLSTSENALTGRI-L 236
Cdd:pfam00989   1 EDLRAILESLPDGIFVVD-EDGRILYVNAAAEELLGLSREEVIGKSLLDLIPEEDdaevAELLRQALLQGEESRGFEVsF 79

                          90       100       110
                  ....*....|....*....|....*....|...
gi 1176461133 237 DLKTGTVKKEGQQSSMRMCMGSR-RSFICRMRC 268
Cdd:pfam00989  80 RVPDGRPRHVEVRASPVRDAGGEiLGFLGVLRD 112

basic helix-loop-helix-Per-ARNT-Sim (bHLH-PAS) domain found in aryl hydrocarbon receptor nuclear translocator (ARNT) and similar proteins; ARNT, also termed Class E basic helix-loop-helix protein 2 (bHLHe2), or Dioxin receptor, nuclear translocator, or hypoxia-inducible factor 1-beta (HIF1b), or HIF-1-beta, or HIF1-beta, is a member of bHLH-PAS transcription regulators that acts as the heterodimeric partner for bHLH-PAS proteins such as aryl hydrocarbon receptor (AhR), hypoxia-inducible factor (HIF), and single-minded (SIM). These bHLH-PAS transcription complexes are involved in transcriptional responses to xenobiotic, hypoxia, and developmental pathways. Heterodimerization of bHLH-PAS proteins with ARNT is mediated by contacts between both the bHLH and the tandem PAS domains. ARNT use bHLH and/or PAS domains to interact with several transcriptional coactivators. It is required for activity of the aryl hydrocarbon (dioxin) receptor.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1176461133  85 KERLARENHSEIERRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMKSLRGTGNTST 149
Cdd:cd18947     1 KERFARENHSEIERRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMKSLRGTGNTST 65

PAS domain; PAS motifs appear in archaea, eubacteria and eukarya. Probably the most surprising identification of a PAS domain was that in EAG-like K+-channels. PAS domains have been found to bind ligands, and to act as sensors for light and oxygen in signal transduction.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1176461133 361 EFISRHNIEGIFTFVDHRCVATVGYQPQELLGKNIVEFCHPEDQQLLRDSFQQVVKlKGQVLSVMFRFRSKNQEWLWMRT 440
Cdd:cd00130     3 DGVIVLDLDGRILYANPAAEQLLGYSPEELIGKSLLDLIHPEDREELRERLENLLS-GGEPVTLEVRLRRKDGSVIWVLV 81

                          90
                  ....*....|....*..
gi 1176461133 441 SSFTFQNPYSDEIEYII 457
Cdd:cd00130    82 SLTPIRDEGGEVIGLLG 98

helix loop helix domain;

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|....*....
gi 1176461133   94 SEIERRRRNKMTAYITELSDMVPTCSAlARKPDKLTILRMAVSHMKSLR 142
Cdd:smart00353   1 NARERRRRRKINEAFDELRSLLPTLPK-NKKLSKAEILRLAIEYIKSLQ 48

PAS domain [Signal transduction mechanisms];

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1176461133 360 TEFISRHNIEGIFTFVDHRCVATVGYQPQELLGKNIVEFCHPEDQQLLRDSFQQVVKLKGQVLSVMFRFRSKNQEWLWMR 439
Cdd:COG2202   147 PDGIFVLDLDGRILYVNPAAEELLGYSPEELLGKSLLDLLHPEDRERLLELLRRLLEGGRESYELELRLKDGDGRWVWVE 226

                          90       100
                  ....*....|....*....|....
gi 1176461133 440 TSSFTFQNpySDEIEYIICTNTNV 463
Cdd:COG2202   227 ASAVPLRD--GGEVIGVLGIVRDI 248

PAS domain; PAS motifs appear in archaea, eubacteria and eukarya. Probably the most surprising identification of a PAS domain was that in EAG-like K+-channels.

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1176461133  165 HLILEAADGFLFIVScETGRVVYVSDSVTPVLNQPQSEWFGSTLYDQVHPDDVDKLREQLSTSEN 229
Cdd:smart00091   4 RAILESLPDGIFVLD-LDGRILYANPAAEELLGYSPEELIGKSLLELIHPEDRERVQEALQRLLS 67

PAS domain S-box; The PAS domain was previously described. This sensory box, or S-box domain occupies the central portion of the PAS domain but is more widely distributed. It is often tandemly repeated. Known prosthetic groups bound in the S-box domain include heme in the oxygen sensor FixL, FAD in the redox potential sensor NifL, and a 4-hydroxycinnamyl chromophore in photoactive yellow protein. Proteins containing the domain often contain other regulatory domains such as response regulator or sensor histidine kinase domains. Other S-box proteins include phytochromes and the aryl hydrocarbon receptor nuclear translocator. [Regulatory functions, Small molecule interactions]

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1176461133 369 EGIFTFVDHRCVATVGYQPQELLGKNIVEFCHPEDQQLLRDSFQQVVKLKGQVLSVMFRFRSKNQEWLWMRTS 441
Cdd:TIGR00229  22 EGNILYVNPAFEEIFGYSAEELIGRNVLELIPEEDREEVRERIERRLEGEPEPVSEERRVRRKDGSEIWVEVS 94

basic helix-loop-helix-Per-ARNT-Sim (bHLH-PAS) domain found in aryl hydrocarbon receptor nuclear translocator (ARNT) and similar proteins; ARNT, also termed Class E basic helix-loop-helix protein 2 (bHLHe2), or Dioxin receptor, nuclear translocator, or hypoxia-inducible factor 1-beta (HIF1b), or HIF-1-beta, or HIF1-beta, is a member of bHLH-PAS transcription regulators that acts as the heterodimeric partner for bHLH-PAS proteins such as aryl hydrocarbon receptor (AhR), hypoxia-inducible factor (HIF), and single-minded (SIM). These bHLH-PAS transcription complexes are involved in transcriptional responses to xenobiotic, hypoxia, and developmental pathways. Heterodimerization of bHLH-PAS proteins with ARNT is mediated by contacts between both the bHLH and the tandem PAS domains. ARNT use bHLH and/or PAS domains to interact with several transcriptional coactivators. It is required for activity of the aryl hydrocarbon (dioxin) receptor.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1176461133  85 KERLARENHSEIERRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMKSLRGTGNTST 149
Cdd:cd18947     1 KERFARENHSEIERRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMKSLRGTGNTST 65

basic helix-loop-helix-Per-ARNT-Sim (bHLH-PAS) domain found in Drosophila melanogaster protein cycle and similar proteins; Protein cycle, also termed brain and muscle ARNT-like 1 (BMAL1), or MOP3, is a putative bHLH-PAS transcription factor involved in the generation of biological rhythms in Drosophila. It activates cycling transcription of Period (PER) and Timeless (TIM) by binding to the E-box (5'-CACGTG-3') present in their promoters.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1176461133  90 RENHSEIERRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMKSLRGTGNTSTD 150
Cdd:cd19726     2 RQNHSEIEKRRRDKMNTYITELSSMIPMCNAMSRKLDKLTVLRMAVQHMKTLRGSLTSYTE 62

basic helix-loop-helix-Per-ARNT-Sim (bHLH-PAS) domain found in aryl hydrocarbon receptor nuclear translocator-like protein 2 (ARNTL2) and similar proteins; ARNTL2, also termed Basic-helix-loop-helix-PAS protein MOP9, or brain and muscle ARNT-like 2 (BMAL2), or CYCLE-like factor (CLIF), or Class E basic helix-loop-helix protein 6 (bHLHe6), or member of PAS protein 9, or PAS domain-containing protein 9 (PASD9), is a neuronal bHLH-PAS transcriptional factor, regulating cell cycle progression and preventing cell death, whose sustained expression might ensure brain neuron survival. It also plays important roles in tumor angiogenesis. ARNT-2 heterodimerize with other bHLH-PAS proteins such as aryl hydrocarbon receptor (AhR), hypoxia-inducible factor (HIF), and single-minded (SIM).

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 1176461133  90 RENHSEIERRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMKSLRGTGNT 147
Cdd:cd11469     2 REAHSQTEKRRRDKMNNLIEELSAMIPQCNPMARKLDKLTVLRMAVQHLKSLKGSTSS 59

PAS fold; The PAS fold corresponds to the structural domain that has previously been defined as PAS and PAC motifs. The PAS fold appears in archaea, eubacteria and eukarya.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1176461133 372 FTFVDHRCVATVGYQPQELLGK--NIVEFCHPEDQQLLRDSFQQVVKlKGQVLSVMFRFRSKNQEWLWMRTSSFTFQNPy 449
Cdd:pfam08447   1 IIYWSPRFEEILGYTPEELLGKgeSWLDLVHPDDRERVREALWEALK-GGEPYSGEYRIRRKDGEYRWVEARARPIRDE- 78

                          90
                  ....*....|.
gi 1176461133 450 SDEIEYIICTN 460
Cdd:pfam08447  79 NGKPVRVIGVA 89

PAS domain; PAS motifs appear in archaea, eubacteria and eukarya. Probably the most surprising identification of a PAS domain was that in EAG-like K+-channels. PAS domains have been found to bind ligands, and to act as sensors for light and oxygen in signal transduction.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1176461133 361 EFISRHNIEGIFTFVDHRCVATVGYQPQELLGKNIVEFCHPEDQQLLRDSFQQVVKlKGQVLSVMFRFRSKNQEWLWMRT 440
Cdd:cd00130     3 DGVIVLDLDGRILYANPAAEQLLGYSPEELIGKSLLDLIHPEDREELRERLENLLS-GGEPVTLEVRLRRKDGSVIWVLV 81

                          90
                  ....*....|....*..
gi 1176461133 441 SSFTFQNPYSDEIEYII 457
Cdd:cd00130    82 SLTPIRDEGGEVIGLLG 98

helix loop helix domain;

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|....*....
gi 1176461133   94 SEIERRRRNKMTAYITELSDMVPTCSAlARKPDKLTILRMAVSHMKSLR 142
Cdd:smart00353   1 NARERRRRRKINEAFDELRSLLPTLPK-NKKLSKAEILRLAIEYIKSLQ 48

PAS domain [Signal transduction mechanisms];

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1176461133 360 TEFISRHNIEGIFTFVDHRCVATVGYQPQELLGKNIVEFCHPEDQQLLRDSFQQVVKLKGQVLSVMFRFRSKNQEWLWMR 439
Cdd:COG2202   147 PDGIFVLDLDGRILYVNPAAEELLGYSPEELLGKSLLDLLHPEDRERLLELLRRLLEGGRESYELELRLKDGDGRWVWVE 226

                          90       100
                  ....*....|....*....|....
gi 1176461133 440 TSSFTFQNpySDEIEYIICTNTNV 463
Cdd:COG2202   227 ASAVPLRD--GGEVIGVLGIVRDI 248

basic helix-loop-helix-orange (bHLH-O) domain found in hairy and enhancer of split (HES)-related repressor protein (HERP)-like family; The HERP-like family includes bHLH-O transcriptional regulators that are related to the Drosophila hairy and Enhancer-of-split proteins. They contain a basic helix-loop-helix (bHLH) domain with an invariant glycine residue in its basic region, an orange domain in the central region and YXXW sequence motif at its C-terminal region. HERP proteins (HEY1, HEY2 and HEYL) act as downstream effectors of Notch signaling. They are involved in cardiovascular development and have roles in somitogenesis, myogenesis and gliogenesis. Hairy and enhancer of split-related protein HELT is a transcriptional repressor expressed in the developing central nervous system. It binds preferentially to the canonical E box sequence 5'-CACGCG-3' and regulates neuronal differentiation and/or identity. Differentially expressed in chondrocytes proteins, DEC1 and DEC2, are widely expressed in both embryonic and adult tissues and have been implicated in apoptosis, cell proliferation, and circadian rhythms, as well as malignancy in various cancers. Drosophila melanogaster protein clockwork orange (Cwo) is also included in this family. It is involved in the regulation of Drosophila circadian rhythms. It functions as both an activator and a repressor of clock gene expression.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 1176461133  93 HSEIERRRRNKMTAYITELSDMVPTCSALAR--KPDKLTILRMAVSHMKSLRGTG 145
Cdd:cd11389     1 HKVIEKRRRDRINESLAELRRLVPEARKSKGsgKLEKAEILEMTLQHLKALQSST 55

PAS domain; PAS motifs appear in archaea, eubacteria and eukarya. Probably the most surprising identification of a PAS domain was that in EAG-like K+-channels.

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1176461133  165 HLILEAADGFLFIVScETGRVVYVSDSVTPVLNQPQSEWFGSTLYDQVHPDDVDKLREQLSTSEN 229
Cdd:smart00091   4 RAILESLPDGIFVLD-LDGRILYANPAAEELLGYSPEELIGKSLLELIHPEDRERVQEALQRLLS 67

PAS domain [Signal transduction mechanisms];

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1176461133 358 QPTEFISRHNIEGIFTFVDHRCVATVGYQPQELLGKNIVEFCHPEDQQLLRDSFQQVVKlKGQVLSVMFRFRSKNQEWLW 437
Cdd:COG2202    19 SSPDAIIITDLDGRILYVNPAFERLTGYSAEELLGKTLRDLLPPEDDDEFLELLRAALA-GGGVWRGELRNRRKDGSLFW 97

                          90       100
                  ....*....|....*....|....*.
gi 1176461133 438 MRTSSFTFQNPySDEIEYIICTNTNV 463
Cdd:COG2202    98 VELSISPVRDE-DGEITGFVGIARDI 122

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in the microphthalmia-associated transcription factor family (MITF) family; The MITF (also known as microphthalmia-TFE, or MiT) family is a small family that contain a basic helix loop helix domain associated with a leucine zipper (bHLHZip). The MITF family comprises four genes in mammals (MITF, TFE3, TFEB, and TFEC); each gene has different functions. MITF is involved in neural crest melanocytes development as well as the pigmented retinal epithelium. TFEB is required for vascularization of the mouse placenta. TFE3 is involved in B cell function. TFEC regulates gene expression in macrophages. The MITF family can form homodimers or heterodimers with each other but not with other bHLH or bHLHzip proteins.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 1176461133  85 KERLARENHSEIERRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMKSLR 142
Cdd:cd11397     1 KDRQKKDNHNMIERRRRFNINDRIKELGTLLPKSNDPDMRWNKGTILKASVDYIRKLQ 58

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in USF/MITF family; The USF (upstream stimulatory factor)/MITF (microphthalmia-associated transcription factor) family includes two bHLHzip transcription factor subfamilies. USFs are ubiquitously expressed and key regulators of a wide number of gene regulation networks, including the stress and immune responses, cell cycle and proliferation, lipid and glucid metabolism. USFs recruit chromatin remodeling enzymes and interact with co-activators and the members of the transcription pre-initiation complex. USFs interact with high affinity to E-box regulatory elements. The MITF (also known as microphthalmia-TFE, or MiT) subfamily comprises four genes in mammals (MITF, TFE3, TFEB, and TFEC); each gene has different functions. MITF is involved in neural crest melanocytes development as well as the pigmented retinal epithelium. TFEB is required for vascularization of the mouse placenta. TFE3 is involved in B cell function. TFEC regulates gene expression in macrophages. The MITF subfamily proteins can form homodimers or heterodimers with each other but not with other bHLH or bHLHzip proteins.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1176461133  92 NHSEIERRRRNKMTAYITELSDMVPTC--SALARKPDKLTILRMAVSHMKSLR 142
Cdd:cd11387     1 SHNAVERRRRDNINEKIQELGSLVPPSrlETKDLKPNKGSILSKAVEYIRELQ 53

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in upstream stimulatory factors, USF1, USF2 and similar proteins; Upstream stimulatory factor 1 and 2 (USF-1 and USF-2) are members of bHLHzip transcription factor family. USFs are ubiquitously expressed and key regulators of a wide number of gene regulation networks, including the stress and immune responses, cell cycle and proliferation, lipid and glucid metabolism. USFs recruit chromatin remodeling enzymes and interact with co-activators and the members of the transcription pre-initiation complex. USFs interact with high affinity to E-box regulatory elements.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1176461133  93 HSEIERRRRNKMTAYITELSDMVPTCSALARK--PDKLTILRMAVSHMKSLR 142
Cdd:cd11396     2 HNEVERRRRDKINNWIVKLAKIVPDCEKDNSKqgQSKGGILSKACDYIQELR 53

basic helix-loop-helix (bHLH) domain found in the spermatogenesis- and oogenesis-specific basic helix-loop-helix-containing protein (SOHLH) family and similar proteins; The SOHLH family includes two bHLH transcription factors, SOHLH1 and SOHLH2. They are specifically in spermatogonia and oocytes and essential for early spermatogonial and oocyte differentiation. The family also includes transcription factor-like 5 protein (TCFL5) and similar proteins. TCFL5, also termed Cha transcription factor, or HPV-16 E2-binding protein 1 (E2BP-1), is a bHLH transcription factor that plays a crucial role in spermatogenesis. It regulates cell proliferation or differentiation of cells through binding to a specific DNA sequence like other bHLH molecules.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1176461133  90 RENHSEIERRRRNKMTAYITELSDMVPTCSalaRKPDKLTILRMAVSHMKSLRG 143
Cdd:cd19683     3 RERHNAKERQRRERIKIACDQLRKLVPGCS---RKTDKATVFEFTVAYIKFLRE 53

basic helix-loop-helix-orange (bHLH-O) domain found in hairy/enhancer-of-split related with YRPW motif-like protein (HEYL) and similar proteins; HEYL, also termed Class B basic helix-loop-helix protein 33 (bHLHb33), or hairy-related transcription factor 3 (HRT-3), is a bHLH-O transcriptional repressor that is strongly expressed in the presomitic mesoderm, the somites, the peripheral nervous system and smooth muscle of all arteries and is a downstream effector of the Notch and transforming growth factor-beta pathways. It promotes neuronal differentiation by activating proneural genes and inhibiting other hairy and enhancer of split (HES) and hairy/enhancer-of-split related with YRPW motif protein (HEY) proteins. HEYL also functions as a tumor suppressor involved in the progression of human cancers.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1176461133  88 LARENHSEI-ERRRRNKMTAYITELSDMVPTC--SALARKPDKLTILRMAVSHMKSLRGTGNT 147
Cdd:cd11447     7 QARKKRRGIiEKRRRDRINSSLSELRRLVPTAfeKQGSSKLEKAEILQMTVDHLKMLHATGGA 69

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in transcription factor E3 (TFE3) and similar proteins; TFE3, also termed Class E basic helix-loop-helix protein 33 (bHLHe33), is a bHLHzip transcription factor that is involved in B cell function. It specifically recognizes and binds E-box sequences (5'-CANNTG-3'). Its efficient DNA-binding requires dimerization with itself or with another MiT/TFE family member such as TFEB or MITF.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1176461133  85 KERLARENHSEIERRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMKSLRGTGNTSTD 150
Cdd:cd18928     7 KERQKKDNHNLIERRRRFNINDRIKELGTLIPKSTDPEMRWNKGTILKASVDYIRKLQKEQQRSKE 72

basic helix-loop-helix-orange (bHLH-O) domain found in hairy and enhancer of split (HES)-related repressor protein (HERP) family; HERP (also called Hey/Hesr/HRT/CHF/gridlock) proteins corresponds to a family of bHLH-O transcriptional repressors that are related to the Drosophila hairy and Enhancer-of-split proteins and act as downstream effectors of Notch signaling. They contain a basic helix-loop-helix (bHLH) domain with an invariant glycine residue in its basic region, an orange domain in the central region and YXXW sequence motif at its C-terminal region. HERP proteins are involved in cardiovascular development and have roles in somitogenesis, myogenesis and gliogenesis.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1176461133  96 IERRRRNKMTAYITELSDMVPTcsALAR----KPDKLTILRMAVSHMKSLRGTG 145
Cdd:cd11407     8 IEKRRRDRINNSLAELRRLVPT--AFEKqgsaKLEKAEILQMTVDHLKMLHSKG 59

basic helix-loop-helix-Per-ARNT-Sim (bHLH-PAS) domain found in Drosophila melanogaster Circadian locomotor output cycles protein kaput (dCLOCK) and similar proteins; dCLOCK, also termed dPAS1, is a bHLH-PAS Circadian regulator that acts as a transcription factor and generates a rhythmic output with a period of about 24 hours.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1176461133  77 DDEQSSADKERLAReNHSEieRRRRNKMTAYITELSDMVptcSALARKPDKLTILRMAVSHMKslrgTGNTSTDGS---- 152
Cdd:cd19735     1 DEEDEKDTIKRKSR-NLSE--KKRRDQFNVLINELCSMV---STSNRKMDKSTVLKSTIAFLK----NHNEVTMQShqqe 70

                          90
                  ....*....|
gi 1176461133 153 ----YKPSFL 158
Cdd:cd19735    71 iqedWKPSFL 80

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in microphthalmia-associated transcription factor (MITF) and similar proteins; MITF, also termed Class E basic helix-loop-helix protein 32 (bHLHe32), is a bHLHzip transcription factor that is involved in neural crest melanocytes development as well as the pigmented retinal epithelium. It regulates the expression of genes with essential roles in cell differentiation, proliferation and survival. It binds to M-boxes (5'-TCATGTG-3') and symmetrical DNA sequences (E-boxes) (5'-CACGTG-3') found in the promoters of target genes, such as BCL2 and tyrosinase (TYR).

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1176461133  79 EQSSADKERLARENHSEIERRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMKSLR 142
Cdd:cd18926     3 EARALAKERQKKDNHNLIERRRRFNINDRIKELGTLIPKSNDPDMRWNKGTILKASVDYIRKLQ 66

basic helix-loop-helix-orange (bHLH-O) domain found in Drosophila melanogaster enhancer of split mbeta protein (ESMB) and similar proteins; ESMB, also termed E(spl)mbeta, or HLH-mbeta, or split locus enhancer protein mA, is a bHLH-O transcriptional repressor of genes that require a bHLH protein for their transcription. It is involved in the neural-epidermal lineage decision during early neurogenesis. The family also includes Enhancer of split m7 protein (also known as E(spl)m7), which acts as a transcriptional repressor that participates in the control of cell fate choice by uncommitted neuroectodermal cells in the embryo.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1176461133  96 IERRRRNKMTAYITELSDMVPTCSALARKPD----KLTILRMAVSHMKSLR 142
Cdd:cd19741    15 LERKRRARINKCLDELKDLMVEALATEAENVskleKADILELTVRHLKKLR 65

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in transcription factor EC (TFEC) and similar proteins; TFEC, also termed Class E basic helix-loop-helix protein 34 (bHLHe34), or transcription factor EC-like (TFEC-L), is a bHLHzip transcriptional regulator that acts as a repressor or an activator and regulates gene expression in macrophages. It plays an important role in the niche to expand hematopoietic progenitors through the modulation of several cytokines.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 1176461133  85 KERLARENHSEIERRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMKSLR 142
Cdd:cd18925     1 KERQKKDNHNLIERRRRYNINYRIKELGTLIPKSNDPDMRWNKGTILKASVEYIKWLQ 58

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in Max-like protein X (Mlx) family; Mlx, also termed Class D basic helix-loop-helix protein 13 (bHLHd13), or Max-like bHLHZip protein, or protein BigMax, or transcription factor-like protein 4, is a Max-like bHLHZip transcription regulator that interacts with the Max network of transcription factors. It forms a sequence-specific DNA-binding protein complex with some member of Mad family (Mad1 and Mad4) and Mondo family but not the Myc family and bind the E-box DNA to control transcription. The family also includes Saccharomyces cerevisiae INO4, which is a bHLH transcriptional activator of phospholipid synthetic genes (such as INO1, CHO1/PSS, CHO2/PEM1, OPI3/PEM2, etc.). It is required for de-repression of phospholipid biosynthetic gene expression in response to inositol deprivation in yeast.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1176461133  90 RENHSEIERRRRNKMTAYITELSDMVPTCSalARKPDKLTILRMAVSHMKSL 141
Cdd:cd11404     3 RLNHVRSEKKRRELIKKGYDELCALVPGLD--PQKRTKADILQKAADWIQEL 52

basic helix-loop-helix-orange (bHLH-O) domain found in HERP/HES-like family; The HERP/HES-like family includes bHLH-O transcriptional regulators that are related to the Drosophila hairy and Enhancer-of-split (HES) proteins. The HERP (HES-related repressor protein) subfamily proteins contain a basic helix-loop-helix (bHLH) domain with an invariant glycine residue in its basic region, an orange domain in the central region and YXXW sequence motif at its C-terminal region. Hairy and enhancer of split (HES)-related repressor protein (HERP) proteins (HEY1, HEY2 and HEYL) act as downstream effectors of Notch signaling. They are involved in cardiovascular development and have roles in somitogenesis, myogenesis and gliogenesis. Hairy and enhancer of split-related protein HELT is a transcriptional repressor expressed in the developing central nervous system. It binds preferentially to the canonical E box sequence 5'-CACGCG-3' and regulates neuronal differentiation and/or identity. Differentially expressed in chondrocytes proteins, DEC1 and DEC2, are widely expressed in both embryonic and adult tissues and have been implicated in apoptosis, cell proliferation, and circadian rhythms, as well as malignancy in various cancers. Drosophila melanogaster protein clockwork orange (Cwo) is also included in this subfamily. It is involved in the regulation of Drosophila circadian rhythms. It functions as both an activator and a repressor of clock gene expression. The HES subfamily proteins contain a basic helix-loop-helix (bHLH) domain with an invariant proline residue in its basic region, an orange domain in the central region and a conserved tetrapeptide motif, WRPW, at its C-terminal region. They form heterodimers or homodimers via their HLH domain and bind DNA to repress gene transcription that play an essential role in development of both compartment and boundary cells of the central nervous system.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 1176461133  96 IERRRRNKMTAYITELSDMVPTCSAL--ARKPDKLTILRMAVSHMKSLR 142
Cdd:cd19685     1 SEKRRRQRINDKLNQLKELLPPNLSKqsRSKLSKAEILEMAITELRRLQ 49

basic helix-loop-helix-Per-ARNT-Sim (bHLH-PAS) domain found in nuclear receptor coactivator 3 (NCoA-3) and similar proteins; NCoA-3, also termed ACTR, or amplified in breast cancer 1 protein (AIB-1), or CBP-interacting protein (pCIP), or Class E basic helix-loop-helix protein 42 (bHLHe42), or receptor-associated coactivator 3 (RAC-3), or steroid receptor coactivator protein 3 (SRC-3), or thyroid hormone receptor activator molecule 1 (TRAM-1), is a bHLH-PAS steroid/nuclear receptor-associated coactivator that directly binds nuclear receptors and stimulates the transcriptional activities in a hormone-dependent fashion. It also plays a central role in creating a multisubunit coactivator complex, which probably acts via remodeling of chromatin.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*....
gi 1176461133  96 IERRRRNKMTAYITELSDMVPT----CSALARKPDKLTILRMAVSHMKSLRGTGNTSTD 150
Cdd:cd18949     5 GEKRRREQESKYIEELAELISAnlsdIDNFNVKPDKCAILKETVRQIRQIKEQGKSSSN 63

basic helix-loop-helix-Per-ARNT-Sim (bHLH-PAS) domain found in Circadian locomotor output cycles protein kaput (CLOCK) and similar proteins; CLOCK, also termed Class E basic helix-loop-helix protein 8 (bHLHe8), is a bHLH-PAS transcriptional activator which forms a core component of the circadian clock. It forms heterodimers with another bHLH-PAS protein, Brain-Muscle-Arnt-Like (also known as BMAL or ARNT3 or mop3), which regulates circadian rhythm. BMAL1-CLOCK heterodimer complex activates transcription from E-box (CANNTG) elements found in the promoter of circadian responsive genes.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1176461133  84 DKERLARENHSEIERRRRNKMTAYITELSDMVPtcsALARKPDKLTILRMAVSHMK 139
Cdd:cd19734     2 DKDKAKRVSRNKSEKKRRDQFNVLIKELGSMLP---GNARKMDKSTVLQKSIDFLR 54

Motif C-terminal to PAS motifs (likely to contribute to PAS structural domain); PAC motif occurs C-terminal to a subset of all known PAS motifs. It is proposed to contribute to the PAS domain fold.

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|.
gi 1176461133  423 SVMFRFRSKNQEWLWMRTSSFTFQNpYSDEIEYIICTNTNV 463
Cdd:smart00086   1 TVEYRLRRKDGSYIWVLVSASPIRD-EDGEVEGILGVVRDI 40

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in Max-associated protein 4 (Mad4) and similar proteins; Mad4, also termed Max dimerization protein 4, or Max dimerizer 4 (MXD4), or Class C basic helix-loop-helix protein 12 (bHLHc12), or Max-interacting transcriptional repressor MAD4, is a bHLHZip Max-interacting transcriptional repressor that suppresses c-myc dependent transformation and is expressed during neural and epidermal differentiation. It is regulated by a transcriptional repressor complex that contains Miz-1 and c-Myc.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1176461133  90 RENHSEIERRRRNKMTAYITELSDMVPTCSALARKpDKLTILRMAVSHMKSL 141
Cdd:cd18929     3 RSSHNELEKHRRAKLRLYLEQLKQLVPLGPDSTRH-TTLSLLKRAKMHIKKL 53

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in the Myc family; The Myc family is a member of the bHLHzip family of transcription factors that play important roles in the control of normal cell proliferation, growth, survival and differentiation. All Myc isoforms contain two independently functioning polypeptide chain regions: N-terminal transactivating residues and a C-terminal bHLHzip segment. The bHLHzip family of bHLH transcription factors are characterized by a highly conserved N-terminal basic region that may bind DNA at a consensus hexanucleotide sequence known as the E-box (CANNTG) followed by HLH and leucine zipper motifs that may interact with other proteins to form homo- and heterodimers. Myc heterodimerizes with Max enabling specific binding to E-box DNA sequences in the promoters of target genes. The Myc proto-oncoprotein family includes at least five different functional members: c-, N-, L-, S- and B-Myc (which is lacking the bHLH domain).

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 1176461133  90 RENHSEIERRRRNKMTAYITELSDMVPtcsALARKPD--KLTILRMAVSHMKSLR 142
Cdd:cd11400     2 RRLHNVLERQRRNDLKNSFEKLRDLVP---ELADNEKasKVVILKKATEYIKQLQ 53

basic helix-loop-helix (bHLH) domain found in Arabidopsis thaliana protein NAI1 and similar proteins; NAI1, also termed AtbHLH20, or EN 27, is a bHLH transcription activator that regulates the expression of at least NAI2, PYK10 and PBP1. It is required for and mediates the formation of endoplasmic reticulum bodies (ER bodies). It plays a role in the symbiotic interactions with the endophytes of the Sebacinaceae fungus family, such as Piriformospora indica and Sebacina.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1176461133  91 ENHSEIERRRRNKMTAYITELSDMVPTCsalaRKPDKLTILRMAVSHMKSLR 142
Cdd:cd11452     4 QDHILAERKRREKLSQRFIALSALVPGL----KKMDKASVLGDAIKHIKQLQ 51

basic helix-loop-helix (bHLH) domain found in Arabidopsis thaliana OBP3-responsive gene 2 (ORG2), 3 (ORG3) and similar proteins; The family includes ORG2 (also termed AtbHLH38, or EN 8) and ORG3 (also termed AtbHLH39, or EN 9), both of which act as bHLH transcription factors.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1176461133  90 RENHSEIERRRRNKMTAYITELSDMVPtcsaLARKPDKLTI---LRMAVSHMKSLR 142
Cdd:cd18914     2 KLLHNDVERQRRQEMASLFSSLRSLLP----LQYIKGKLSVsdhVDEAVNYIKELQ 53

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in Saccharomyces cerevisiae transcription factor HMS1 and similar proteins; HMS1, also termed high-copy MEP suppressor protein 1, is a putative bHLHzip transcription factor involved in exit from mitosis and pseudohyphal differentiation.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1176461133  93 HSEIERRRRNKMTAYITELSDMVPTC-------------------SALARKPDKLTILRMAVSHMKSLRG 143
Cdd:cd11399     7 HNMIEKRYRSNINDRIAELRDSVPALreayksargededeedlggLTPATKLNKATILSKATEYIRHLEK 76

basic helix-loop-helix-Per-ARNT-Sim (bHLH-PAS) domain found in steroid receptor coactivator (SRC) family; The SRC family of coactivators includes SRC-1 (NcoA-1/p160), SRC-2(TIF2/GRIP1/NcoA-2) and SRC-3(NcoA-3/pCIP/RAC3/ACTR/pCIP/AIB1/TRAM1), which are critical mediators of steroid receptor action. They contain bHLH-PAS domain at the N-terminal that is followed by receptor interacting domain and C-terminal transcriptional activation domain. SRC coactivators interact with nuclear receptors in a ligand-dependent manner and enhance transcriptional activation by the receptor via histone acetylation/methylation.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1176461133  97 ERRRRNKMTAYITEL--------SDMvptcSALARKPDKLTILRMAVSHMKSLR 142
Cdd:cd11439     6 EKRRREQENKYIEELaelisasiSDM----DSLSVKPDKCAILQETVKQIRQIK 55

basic helix-loop-helix (bHLH) domain found in Arabidopsis thaliana protein ABA-INDUCIBLE bHLH-TYPE (AIB) and similar proteins; The family includes several bHLH transcription factors from Arabidopsis thaliana, such as AIB and MYC proteins (MYC2, MYC3 and MYC4). AIB, also termed AtbHLH17, or EN 35, is a transcription activator that regulates positively abscisic acid (ABA) response. MYC2, also termed protein jasmonate insensitive 1, or R-homologous Arabidopsis protein 1 (RAP-1), or AtbHLH6, or EN 38, or Z-box binding factor 1 protein, is a transcriptional activator involved in abscisic acid (ABA), jasmonic acid (JA), and light signaling pathways. MYC3, also termed protein altered tryptophan regulation 2, or AtbHLH5, or transcription factor ATR2, or EN 36, is a transcription factor involved in tryptophan, jasmonic acid (JA) and other stress-responsive gene regulation. MYC4, also termed AtbHLH4, or EN 37, is a transcription factor involved in jasmonic acid (JA) gene regulation. MYC2, together with MYC3 and MYC4, controls additively subsets of JA-dependent responses.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1176461133  92 NHSEIERRRRNKMTAYITELSDMVPTCSalarKPDKLTILRMAVSHMKSLR 142
Cdd:cd11449     8 NHVEAERQRREKLNQRFYALRAVVPNVS----KMDKASLLGDAISYINELK 54

basic helix-loop-helix-Per-ARNT-Sim (bHLH-PAS) domain found in aryl hydrocarbon receptor repressor (AhRR) and similar proteins; AhRR, also termed AhR repressor, or Class E basic helix-loop-helix protein 77 (bHLHe77), is a member of bHLH-PAS transcription factors that acts as a negative regulator of AhR (or Dioxin Receptor), playing key roles in development and environmental sensing. AhR is activated by Dioxin to control the expression of certain genes to influence biological processes such as apoptosis, proliferation, cell growth and differentiation. To form active DNA binding complexes, AhR dimerizes with a bHLH-PAS factor ARNT (Aryl hydrocarbon Nuclear Receptor Translocator). AhRR functions by competing with AhR for its partner ARNT. AhRR-ARNT complexes are transcriptionally inactive.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1176461133  94 SEIERRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMK 139
Cdd:cd11435     5 SNPSKRHRDRLNAELDHLASLLPFPPDIISKLDKLSVLRLSVSYLR 50

basic helix-loop-helix-orange (bHLH-O) domain found in Drosophila melanogaster Enhancer of split proteins, E(spl)m5, E(spl)m8 and similar proteins; The family includes two bHLH-O transcriptional repressors, E(spl)m5 and E(spl)m8, which participate in the control of cell fate choice by uncommitted neuroectodermal cells in the embryo. They bind DNA on N-box motifs, 5'-CACNAG-3'.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1176461133  96 IERRRRNKMTAYITELSDMVPTCSAL--ARKPDKLTILRMAVSHMKSLRGTGN 146
Cdd:cd18916     7 LERQRRARINKCLSELKTLVAECSGDdgCLRMDKAEMLETAVAFMRQQQTAKN 59

basic helix-loop-helix-Per-ARNT-Sim (bHLH-PAS) domain found in hypoxia-inducible factor (HIF) family; The HIF family contains bHLH-PAS transcription regulators involved in oxygen homeostasis, including HIF1a, HIF2a, and HIF3a. They have been implicated in development, postnatal physiology as well as disease pathogenesis. HIF1a, also termed HIF-1-alpha, or HIF1-alpha, or ARNT-interacting protein, or Basic-helix-loop-helix-PAS protein MOP1, or Class E basic helix-loop-helix protein 78 (bHLHe78), or Member of PAS protein 1, or PAS domain-containing protein 8 (PASD8), functions as a master transcriptional regulator of the adaptive response to hypoxia. HIF2a, also termed HIF-2-alpha, or HIF2-alpha, or endothelial PAS domain-containing protein 1 (EPAS-1), or Basic-helix-loop-helix-PAS protein MOP2, or Class E basic helix-loop-helix protein 73 (bHLHe73), or Member of PAS protein 2, or PAS domain-containing protein 2 (PASD2), or HIF-1-alpha-like factor (HLF), is a bHLH-PAS transcription factor involved in the induction of oxygen regulated genes. HIF3a, also termed HIF-3-alpha, or HIF3-alpha, or endothelial PAS domain-containing protein 1 (EPAS-1), or Basic-helix-loop-helix-PAS protein MOP7, or Class E basic helix-loop-helix protein 17 (bHLHe17), or Member of PAS protein 7, or PAS domain-containing protein 7 (PASD7), or HIF3-alpha-1, or inhibitory PAS domain protein (IPAS), is a bHLH-PAS transcriptional regulator in adaptive response to low oxygen tension. It plays a role in the regulation of hypoxia-inducible gene expression.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 1176461133  98 RRRRNKMTAYITELSDMVPTCSALARKPDKLTILRMAVSHMK 139
Cdd:cd11433    10 RCRRGKESEIFYELAHQLPLPHSVSSQLDKASIMRLTISYLK 51