seven-transmembrane G protein-coupled receptor superfamily; This hierarchical evolutionary model represents the seven-transmembrane (7TM) receptors, often referred to as G protein-coupled receptors (GPCRs), which transmit physiological signals from the outside of the cell to the inside via G proteins. GPCRs constitute the largest known superfamily of transmembrane receptors across the three kingdoms of life that respond to a wide variety of extracellular stimuli including peptides, lipids, neurotransmitters, amino acids, hormones, and sensory stimuli such as light, smell and taste. All GPCRs share a common structural architecture comprising of seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops. A general feature of GPCR signaling is agonist-induced conformational changes in the receptors, leading to activation of the heterotrimeric G proteins, which consist of the guanine nucleotide-binding G-alpha subunit and the dimeric G-beta-gamma subunits. The activated G proteins then bind to and activate numerous downstream effector proteins, which generate second messengers that mediate a broad range of cellular and physiological processes. However, some 7TM receptors, such as the type 1 microbial rhodopsins, do not activate G proteins. Based on sequence similarity, GPCRs can be divided into six major classes: class A (the rhodopsin-like family), class B (the Methuselah-like, adhesion and secretin-like receptor family), class C (the metabotropic glutamate receptor family), class D (the fungal mating pheromone receptors), class E (the cAMP receptor family), and class F (the frizzled/smoothened receptor family). Nearly 800 human GPCR genes have been identified and are involved essentially in all major physiological processes. Approximately 40% of clinically marketed drugs mediate their effects through modulation of GPCR function for the treatment of a variety of human diseases including bacterial infections.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 700630476   1 WAILCLGWHRdirrnspdtkghialpaAAKRHGGSGSgntaqhDLARNNFVCFVAWGLPAFQTAAVIVMRLVDADELLGA 80
Cdd:cd13951  112 WVILTLTWFL-----------------SAGLKWSSEA------IEKKSSYFHLVAWGLPAVLTIAVLVLRKVDGDELTGI 168

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*...
gi 700630476  81 CFVGNQSDKALQVLVATPVFCYWIFGSMNLISGYLVHCRNKEILRNSN 128
Cdd:cd13951  169 CFVGNQNLDALRGFVLAPLFLYLILGTVFLLCGFLSLFRIRSILSNDG 216

class F frizzled/smoothened family, member of the 7-transmembrane G protein-coupled receptor superfamily; The class F G protein-coupled receptors includes the frizzled (FZD) family of seven-transmembrane proteins consisting of 10 isoforms (FZD1-10) in mammals. The FZDs are activated by the wingless/int-1 (WNT) family of secreted lipoglycoproteins and preferentially couple to stimulatory G proteins of the Gs family, which activate adenylate cyclase, but can also couple to G proteins of the Gi/Gq families. In the WNT/beta-catenin signaling pathway, the WNT ligand binds to FZD and a lipoprotein receptor-related protein (LRP) co-receptor. This leads to the stabilization and translocation of beta-catenin to the nucleus, where it induces the activation of TCF/LEF family transcription factors. The conserved cytoplasmic motif of FZD, Lys-Thr-X-X-X-Trp, is required for activation of the WNT/beta-catenin pathway, and for membrane localization and phosphorylation of Dsh (dishevelled) protein, a key component of the WNT pathway that relays the WNT signals from the activated receptor to downstream effector proteins. Also included in the class F family is the closely related smoothened (SMO), which is a transmembrane G protein-coupled receptor that acts as the transducer of the hedgehog (HH) signaling pathway. SMO is activated by the hedgehog (HH) family of proteins acting on the 12-transmembrane domain receptor patched (PTCH), which constitutively inhibits SMO. Thus, in the absence of HH proteins, PTCH inhibits SMO signaling. On the other hand, binding of HH to the PTCH receptor activates its internalization and degradation, thereby releasing the PTCH inhibition of SMO. This allows SMO to trigger intracellular signaling and the subsequent activation of the Gli family of zinc finger transcriptional factors and induction of HH target gene expression (PTCH, Gli1, cyclin, Bcl-2, etc). The WNT and HH signaling pathways play critical roles in many developmental processes, such as cell-fate determination, cell proliferation, neural patterning, stem cell renewal, tissue homeostasis and repair, and tumorigenesis, among many others.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 700630476   1 WAILCLGWHRdirrnspdtkghialpaAAKRHGGSGSgntaqhDLARNNFVCFVAWGLPAFQTAAVIVMRLVDADELLGA 80
Cdd:cd13951  112 WVILTLTWFL-----------------SAGLKWSSEA------IEKKSSYFHLVAWGLPAVLTIAVLVLRKVDGDELTGI 168

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*...
gi 700630476  81 CFVGNQSDKALQVLVATPVFCYWIFGSMNLISGYLVHCRNKEILRNSN 128
Cdd:cd13951  169 CFVGNQNLDALRGFVLAPLFLYLILGTVFLLCGFLSLFRIRSILSNDG 216

class F frizzled/smoothened family, member of the 7-transmembrane G protein-coupled receptor superfamily; The class F G protein-coupled receptors includes the frizzled (FZD) family of seven-transmembrane proteins consisting of 10 isoforms (FZD1-10) in mammals. The FZDs are activated by the wingless/int-1 (WNT) family of secreted lipoglycoproteins and preferentially couple to stimulatory G proteins of the Gs family, which activate adenylate cyclase, but can also couple to G proteins of the Gi/Gq families. In the WNT/beta-catenin signaling pathway, the WNT ligand binds to FZD and a lipoprotein receptor-related protein (LRP) co-receptor. This leads to the stabilization and translocation of beta-catenin to the nucleus, where it induces the activation of TCF/LEF family transcription factors. The conserved cytoplasmic motif of FZD, Lys-Thr-X-X-X-Trp, is required for activation of the WNT/beta-catenin pathway, and for membrane localization and phosphorylation of Dsh (dishevelled) protein, a key component of the WNT pathway that relays the WNT signals from the activated receptor to downstream effector proteins. Also included in the class F family is the closely related smoothened (SMO), which is a transmembrane G protein-coupled receptor that acts as the transducer of the hedgehog (HH) signaling pathway. SMO is activated by the hedgehog (HH) family of proteins acting on the 12-transmembrane domain receptor patched (PTCH), which constitutively inhibits SMO. Thus, in the absence of HH proteins, PTCH inhibits SMO signaling. On the other hand, binding of HH to the PTCH receptor activates its internalization and degradation, thereby releasing the PTCH inhibition of SMO. This allows SMO to trigger intracellular signaling and the subsequent activation of the Gli family of zinc finger transcriptional factors and induction of HH target gene expression (PTCH, Gli1, cyclin, Bcl-2, etc). The WNT and HH signaling pathways play critical roles in many developmental processes, such as cell-fate determination, cell proliferation, neural patterning, stem cell renewal, tissue homeostasis and repair, and tumorigenesis, among many others.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 700630476   1 WAILCLGWHRdirrnspdtkghialpaAAKRHGGSGSgntaqhDLARNNFVCFVAWGLPAFQTAAVIVMRLVDADELLGA 80
Cdd:cd13951  112 WVILTLTWFL-----------------SAGLKWSSEA------IEKKSSYFHLVAWGLPAVLTIAVLVLRKVDGDELTGI 168

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*...
gi 700630476  81 CFVGNQSDKALQVLVATPVFCYWIFGSMNLISGYLVHCRNKEILRNSN 128
Cdd:cd13951  169 CFVGNQNLDALRGFVLAPLFLYLILGTVFLLCGFLSLFRIRSILSNDG 216

class F frizzled subfamily 4, member of 7-transmembrane G protein-coupled receptors; This group includes subfamily 4 of the frizzled (FZD) family of seven transmembrane-spanning proteins, which constitute a novel and separate class of GPCRs, and its closely related proteins. This class F protein family consists of 10 isoforms (FZD1-10) in mammals. The FZDs are activated by the wingless/int-1 (WNT) family of secreted lipoglycoproteins and preferentially couple to stimulatory G proteins of the Gs family, which activate adenylate cyclase, but can also couple to G proteins of the Gi/Gq families. In the WNT/beta-catenin signaling pathway, the WNT ligand binds to FZD and a lipoprotein receptor-related protein (LRP) co-receptor. This leads to the stabilization and translocation of beta-catenin to the nucleus, where it induces the activation of TCF/LEF family transcription factors. The conserved cytoplasmic motif of FZD, Lys-Thr-X-X-X-Trp, is required for activation of the WNT/beta-catenin pathway, and for membrane localization and phosphorylation of Dsh (dishevelled) protein, a key component of the WNT pathway that relays the WNT signals from the activated receptor to downstream effector proteins. The WNT pathway plays a critical role in many developmental processes, such as cell-fate determination, cell proliferation, neural patterning, stem cell renewal, tissue homeostasis and repair, and tumorigenesis, among many others.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 700630476  53 FVAWGLPAFQTAAVIVMRLVDADELLGACFVGNQSDKALQVLVATPVFCYWIFGSMNLISGYLVHCRNKEILRN 126
Cdd:cd15038  142 IAAWALPAVKTIVILVMRVVDADELTGLCYVGNQNLDALLGFVVAPLFTYLVIGTLFLIAGFVALFRIRSQLQR 215

class F frizzled subfamilies 5, 8 and related proteins; member of 7-transmembrane G protein-coupled receptors; This group includes subfamilies 5 and 8 of the frizzled (FZD) family of seven transmembrane-spanning proteins, which constitute a novel and separate class of GPCRs, as well as their closely related proteins. This class F protein family consists of 10 isoforms (FZD1-10) in mammals. The FZDs are activated by the wingless/int-1 (WNT) family of secreted lipoglycoproteins and preferentially couple to stimulatory G proteins of the Gs family, which activate adenylate cyclase, but can also couple to G proteins of the Gi/Gq families. In the WNT/beta-catenin signaling pathway, the WNT ligand binds to FZD and a lipoprotein receptor-related protein (LRP) co-receptor. This leads to the stabilization and translocation of beta-catenin to the nucleus, where it induces the activation of TCF/LEF family transcription factors. The conserved cytoplasmic motif of FZD, Lys-Thr-X-X-X-Trp, is required for activation of the WNT/beta-catenin pathway, and for membrane localization and phosphorylation of Dsh (dishevelled) protein, a key component of the WNT pathway that relays the WNT signals from the activated receptor to downstream effector proteins. The WNT pathway plays a critical role in many developmental processes, such as cell-fate determination, cell proliferation, neural patterning, stem cell renewal, tissue homeostasis and repair, and tumorigenesis, among many others.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 700630476  53 FVAWGLPAFQTAAVIVMRLVDADELLGACFVGNQSDKALQVLVATPVFCYWIFGSMNLISGY--LVHCRN 120
Cdd:cd15035  136 LVAWLIPAVQTIAILALSAVDGDPISGICYVGNQNLNNLRGFVLAPLVVYLILGTSFLLAGFvsLFRIRN 205

class F frizzled subfamily 9, member of 7-transmembrane G protein-coupled receptors; This group includes subfamily 9 of the frizzled (FZD) family of seven transmembrane-spanning proteins, which constitute a novel and separate class of GPCRs, and its closely related proteins. This class F protein family consists of 10 isoforms (FZD1-10) in mammals. The FZDs are activated by the wingless/int-1 (WNT) family of secreted lipoglycoproteins and preferentially couple to stimulatory G proteins of the Gs family, which activate adenylate cyclase, but can also couple to G proteins of the Gi/Gq families. In the WNT/beta-catenin signaling pathway, the WNT ligand binds to FZD and a lipoprotein receptor-related protein (LRP) co-receptor. This leads to the stabilization and translocation of beta-catenin to the nucleus, where it induces the activation of TCF/LEF family transcription factors. The conserved cytoplasmic motif of FZD, Lys-Thr-X-X-X-Trp, is required for activation of the WNT/beta-catenin pathway, and for membrane localization and phosphorylation of Dsh (dishevelled) protein, a key component of the WNT pathway that relays the WNT signals from the activated receptor to downstream effector proteins. The WNT pathway plays a critical role in many developmental processes, such as cell-fate determination, cell proliferation, neural patterning, stem cell renewal, tissue homeostasis and repair, and tumorigenesis, among many others.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 700630476  46 ARNNFVCFVAWGLPAFQTAAVIVMRLVDADELLGACFVGNQSDKALQVLVATPVFCYWIFGSMNLISGY--LVHCR 119
Cdd:cd15036  133 SHGSYFHMAAWGIPALKTIVILTMRKVAGDELTGLCYVGSMDVSALTGFVLVPLSCYLVTGTSFLLTGFvaLFHIR 208

class F insect frizzled subfamily 1, member of 7-transmembrane G protein-coupled receptors; This group includes subfamily 1 of the frizzled (FZD) family of seven transmembrane-spanning proteins, which constitute a novel and separate class of G-protein coupled receptors, found in insects such as Drosophila melanogaster. This class F protein family consists of 10 isoforms (FZD1-10) in mammals. The FZDs are activated by the wingless/int-1 (WNT) family of secreted lipoglycoproteins and preferentially couple to stimulatory G proteins of the Gs family, which activate adenylate cyclase, but can also couple to G proteins of the Gi/Gq families. In the WNT/beta-catenin signaling pathway, the WNT ligand binds to FZD and a lipoprotein receptor-related protein (LRP) co-receptor. This leads to the stabilization and translocation of beta-catenin to the nucleus, where it induces the activation of TCF/LEF family transcription factors. The conserved cytoplasmic motif of FZD, Lys-Thr-X-X-X-Trp, is required for activation of the WNT/beta-catenin pathway, and for membrane localization and phosphorylation of Dsh (dishevelled) protein, a key component of the WNT pathway that relays the WNT signals from the activated receptor to downstream effector proteins. The WNT pathway plays a critical role in many developmental processes, such as cell-fate determination, cell proliferation, neural patterning, stem cell renewal, tissue homeostasis and repair, and tumorigenesis, among many others.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 700630476  46 ARNNFVCFVAWGLPAFQTAAVIVMRLVDADELLGACFVGNQSDKALQVLVATPVFCYWIFGSMNLISGYLVHCRNKEILR 125
Cdd:cd15248  141 AKSHYFHLVAWAVPALKTISILAMGKVEGDVLSGVCYVGLWDMHALRGFVLAPLCVYLSLGTIFLLAGFISLFRIRTVMK 220

class F mammalian frizzled subfamily 1, member of 7-transmembrane G protein-coupled receptors; This group includes subfamily 1 of the frizzled (FZD) family of seven transmembrane-spanning proteins, which constitute a novel and separate class of G-protein coupled receptors. This class F protein family consists of 10 isoforms (FZD1-10) in mammals. The FZDs are activated by the wingless/int-1 (WNT) family of secreted lipoglycoproteins and preferentially couple to stimulatory G proteins of the Gs family, which activate adenylate cyclase, but can also couple to G proteins of the Gi/Gq families. In the WNT/beta-catenin signaling pathway, the WNT ligand binds to FZD and a lipoprotein receptor-related protein (LRP) co-receptor. This leads to the stabilization and translocation of beta-catenin to the nucleus, where it induces the activation of TCF/LEF family transcription factors. The conserved cytoplasmic motif of FZD, Lys-Thr-X-X-X-Trp, is required for activation of the WNT/beta-catenin pathway, and for membrane localization and phosphorylation of Dsh (dishevelled) protein, a key component of the WNT pathway that relays the WNT signals from the activated receptor to downstream effector proteins. The WNT pathway plays a critical role in many developmental processes, such as cell-fate determination, cell proliferation, neural patterning, stem cell renewal, tissue homeostasis and repair, and tumorigenesis, among many others.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 700630476  46 ARNNFVCFVAWGLPAFQTAAVIVMRLVDADELLGACFVGNQSDKALQVLVATPVFCYWIFGSMNLISGYLVHCRNKEILR 125
Cdd:cd15247  144 ANSQYFHLAAWAVPAIKTITILAVGQVDGDVLSGVCFVGINNVDALRGFVLAPLFVYLFIGTSFLLAGFVSLFRIRTIMK 223

                 .
gi 700630476 126 N 126
Cdd:cd15247  224 H 224

class F frizzled subfamily 8, member of 7-transmembrane G protein-coupled receptors; This group includes subfamily 8 of the frizzled (FZD) family of seven transmembrane-spanning proteins, which constitute a novel and separate class of GPCRs, and its closely related proteins. This class F protein family consists of 10 isoforms (FZD1-10) in mammals. The FZDs are activated by the wingless/int-1 (WNT) family of secreted lipoglycoproteins and preferentially couple to stimulatory G proteins of the Gs family, which activate adenylate cyclase, but can also couple to G proteins of the Gi/Gq families. In the WNT/beta-catenin signaling pathway, the WNT ligand binds to FZD and a lipoprotein receptor-related protein (LRP) co-receptor. This leads to the stabilization and translocation of beta-catenin to the nucleus, where it induces the activation of TCF/LEF family transcription factors. The conserved cytoplasmic motif of FZD, Lys-Thr-X-X-X-Trp, is required for activation of the WNT/beta-catenin pathway, and for membrane localization and phosphorylation of Dsh (dishevelled) protein, a key component of the WNT pathway that relays the WNT signals from the activated receptor to downstream effector proteins. The WNT pathway plays a critical role in many developmental processes, such as cell-fate determination, cell proliferation, neural patterning, stem cell renewal, tissue homeostasis and repair, and tumorigenesis, among many others.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 700630476  55 AWGLPAFQTAAVIVMRLVDADELLGACFVGNQSDKALQVLVATPVFCYWIFGSMNLISGYLVHCRNKEILR 125
Cdd:cd15250  144 AWLIPSVKSIAVLALSSVDGDPVAGICYVGNQNLDNLRGFVLAPLVIYLFIGTMFLLAGFVSLFRIRSVIK 214

class F frizzled subfamilies 3, 6 and related proteins; member of 7-transmembrane G protein-coupled receptors; This group includes subfamilies 3 and 6 of the frizzled (FZD) family of seven transmembrane-spanning proteins, which constitute a novel and separate class of GPCRs, and their closely related proteins. This class F protein family consists of 10 isoforms (FZD1-10) in mammals. The FZDs are activated by the wingless/int-1 (WNT) family of secreted lipoglycoproteins and preferentially couple to stimulatory G proteins of the Gs family, which activate adenylate cyclase, but can also couple to G proteins of the Gi/Gq families. In the WNT/beta-catenin signaling pathway, the WNT ligand binds to FZD and a lipoprotein receptor-related protein (LRP) co-receptor. This leads to the stabilization and translocation of beta-catenin to the nucleus, where it induces the activation of TCF/LEF family transcription factors. The conserved cytoplasmic motif of FZD, Lys-Thr-X-X-X-Trp, is required for activation of the WNT/beta-catenin pathway, and for membrane localization and phosphorylation of Dsh (dishevelled) protein, a key component of the WNT pathway that relays the WNT signals from the activated receptor to downstream effector proteins. The WNT pathway plays a critical role in many developmental processes, such as cell-fate determination, cell proliferation, neural patterning, stem cell renewal, tissue homeostasis and repair, and tumorigenesis, among many others.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 700630476  54 VAWGLPAFQTAAVIVMRLVDADELLGACFVGNQSDKALQVLVATPVFCYWIFGSMNLISGYL 115
Cdd:cd15910  143 LAWGIPGVLTMVLLATNKIEGDNISGVCFVGLYDSDGLRFFVLLPLCLYVLVGMSLLLAGII 204

class F frizzled subfamily 3, member of 7-transmembrane G protein-coupled receptors; This group includes subfamily 3 of the frizzled (FZD) family of seven transmembrane-spanning proteins, which constitute a novel and separate class of GPCRs, and its closely related proteins. This class F protein family consists of 10 isoforms (FZD1-10) in mammals. The FZDs are activated by the wingless/int-1 (WNT) family of secreted lipoglycoproteins and preferentially couple to stimulatory G proteins of the Gs family, which activate adenylate cyclase, but can also couple to G proteins of the Gi/Gq families. In the WNT/beta-catenin signaling pathway, the WNT ligand binds to FZD and a lipoprotein receptor-related protein (LRP) co-receptor. This leads to the stabilization and translocation of beta-catenin to the nucleus, where it induces the activation of TCF/LEF family transcription factors. The conserved cytoplasmic motif of FZD, Lys-Thr-X-X-X-Trp, is required for activation of the WNT/beta-catenin pathway, and for membrane localization and phosphorylation of Dsh (dishevelled) protein, a key component of the WNT pathway that relays the WNT signals from the activated receptor to downstream effector proteins. The WNT pathway plays a critical role in many developmental processes, such as cell-fate determination, cell proliferation, neural patterning, stem cell renewal, tissue homeostasis and repair, and tumorigenesis, among many others.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|
gi 700630476  54 VAWGLPAFQTAAVIVMRLVDADELLGACFVGNQSDKALQVLVATPVFCYWIFGSMNLISG 113
Cdd:cd15033  143 SAWGIPGTLTIILLAMNKIEGDNISGVCFVGLYDVDALRYFVLAPLCLDVVVGVSLLLAG 202