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.

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gi 1183154130   1 GCYIEGFFATLGGEIALWSLVVLAIERYVVVCKPMSNFRFGENHA 45
Cdd:cd15080    72 GCNLEGFFATLGGEIALWSLVVLAIERYVVVCKPMSNFRFGENHA 116

medium wave-sensitive opsins, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes Medium Wave-Sensitive opsin, which mediates visual transduction in response to light at medium wavelengths (green). Vertebrate cone opsins are expressed in cone photoreceptor cells of the retina and involved in mediating photopic vision, which allows color perception. The cone opsins can be classified into four classes according to their peak absorption wavelengths: SWS1 (ultraviolet sensitive), SWS2 (short wave-sensitive), MWS/LWS (medium/long wave-sensitive), and RH2 (medium wave-sensitive, rhodopsin-like opsins). Members of this group belong to the class A of the G protein-coupled receptors and possess seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops.

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gi 1183154130   1 GCYIEGFFATLGGEIALWSLVVLAIERYVVVCKPMSNFRFGENHA 45
Cdd:cd15080    72 GCNLEGFFATLGGEIALWSLVVLAIERYVVVCKPMSNFRFGENHA 116

medium wave-sensitive opsins, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes Medium Wave-Sensitive opsin, which mediates visual transduction in response to light at medium wavelengths (green). Vertebrate cone opsins are expressed in cone photoreceptor cells of the retina and involved in mediating photopic vision, which allows color perception. The cone opsins can be classified into four classes according to their peak absorption wavelengths: SWS1 (ultraviolet sensitive), SWS2 (short wave-sensitive), MWS/LWS (medium/long wave-sensitive), and RH2 (medium wave-sensitive, rhodopsin-like opsins). Members of this group belong to the class A of the G protein-coupled receptors and possess seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops.

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gi 1183154130   1 GCYIEGFFATLGGEIALWSLVVLAIERYVVVCKPMSNFRFGENHA 45
Cdd:cd15080    72 GCNLEGFFATLGGEIALWSLVVLAIERYVVVCKPMSNFRFGENHA 116

non-visual pinopsins, member of the class A family of seven-transmembrane G protein-coupled receptors; Pinopsins are found in the pineal organ of birds, reptiles and amphibians, but are absent from teleosts and mammals. The vertebrate non-visual opsin family includes pinopsins, parapinopsin, VA (vertebrate ancient) opsins, and parietopsins. These non-visual opsins are expressed in various extra-retinal tissues and/or in non-rod, non-cone retinal cells. They are thought to be involved in light-dependent physiological functions such as photo-entrainment of circadian rhythm, photoperiodicity and body color change. Pinopsins belong the class A of the G protein-coupled receptors and possess seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops.

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gi 1183154130   2 CYIEGFFATLGGEIALWSLVVLAIERYVVVCKPMSNFRFGENHA 45
Cdd:cd15084    83 CEFEGFMVSLTGIVGLWSLAILAFERYLVICKPMGDFRFQQRHA 126

non-visual VA (vertebrate ancient) opsins, member of the class A family of seven-transmembrane G protein-coupled receptors; The vertebrate ancient (VA) opsin photopigments were originally identified in salmon and they appear to have diverged early in the evolution of vertebrate opsins. VA opsins are localized in the inner retina and the brain in teleosts. The vertebrate non-visual opsin family includes pinopsins, parapinopsin, VA (vertebrate ancient) opsins, and parietopsins. These non-visual opsins are expressed in various extraretinal tissues and/or in non-rod, non-cone retinal cells. They are thought to be involved in light-dependent physiological functions such as photo-entrainment of circadian rhythm, photoperiodicity, and body color change. The VA opsins belong the class A of the G protein-coupled receptors and possess seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops.

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gi 1183154130   2 CYIEGFFATLGGEIALWSLVVLAIERYVVVCKPMSNFRFGENHA 45
Cdd:cd15082    86 CVLEGFAVTFFGIVALWSLAVLAFERFFVICRPLGNIRLQGKHA 129

long wave-sensitive opsins, member of the class A family of seven-transmembrane G protein-coupled receptors; Long Wave-Sensitive opsin is also called red-sensitive opsin or red cone photoreceptor pigment, which mediates visual transduction in response to light at long wavelengths. Vertebrate cone opsins are expressed in cone photoreceptor cells of the retina and involved in mediating photopic vision, which allows color perception. The cone opsins can be classified into four classes according to their peak absorption wavelengths: SWS1 (ultraviolet sensitive), SWS2 (short wave-sensitive), MWS/LWS (medium/long wave-sensitive), and RH2 (medium wave-sensitive, rhodopsin-like opsins). Members of this group belong to the class A of the G protein-coupled receptors and possess seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops.

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gi 1183154130   2 CYIEGFFATLGGEIALWSLVVLAIERYVVVCKPMSNFRFGENHA 45
Cdd:cd15081    85 CVLEGFTVSVCGITGLWSLTIISWERWVVVCKPFGNIKFDGKLA 128

non-visual parietopsins, member of the class A family of seven-transmembrane G protein-coupled receptors; Parietopsin is a non-visual green light-sensitive opsin that was initially identified in the parietal eye of lizards. The vertebrate non-visual opsin family includes pinopsins, parapinopsin, VA (vertebrate ancient) opsins, and parietopsins. These non-visual opsins are expressed in various extra-retinal tissues and/or in non-rod, non-cone retinal cells. They are thought to be involved in light-dependent physiological functions such as photo-entrainment of circadian rhythm, photoperiodicity and body color change. Parietopsin belongs to the class A of the G protein-coupled receptors and shows strong homology to the vertebrate visual opsins.

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gi 1183154130   2 CYIEGFFATLGGEIALWSLVVLAIERYVVVCKPMSNFR 39
Cdd:cd15085    73 CIFQGFAVNYFGIVSLWSLTLLAYERYNVVCKPMGGLK 110

rhodopsin receptor-like class A family of the seven-transmembrane G protein-coupled receptor superfamily; Class A rhodopsin-like receptors constitute about 90% of all GPCRs. The class A GPCRs include the light-sensitive rhodopsin as well as receptors for biogenic amines, lipids, nucleotides, odorants, peptide hormones, and a variety of other ligands. All GPCRs have 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. Based on sequence similarity, GPCRs can be divided into six major classes: class A (rhodopsin-like family), class B (Methuselah-like, adhesion and secretin-like receptor family), class C (metabotropic glutamate receptor family), class D (fungal mating pheromone receptors), class E (cAMP receptor family), and class F (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.

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gi 1183154130   2 CYIEGFFATLGGEIALWSLVVLAIERYVVVCKPMS 36
Cdd:cd00637    71 CKLLGFLQSVSLLASILTLTAISVDRYLAIVHPLR 105

glycoprotein hormone receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; The glycoprotein hormone receptors (GPHRs) are seven transmembrane domain receptors with a very large extracellular N-terminal domain containing many leucine-rich repeats responsible for hormone recognition and binding. The glycoprotein hormone family includes three gonadotropins: luteinizing hormone (LH), follicle-stimulating hormone (FSH), chorionic gonadotropin (CG) and a pituitary thyroid-stimulating hormone (TSH). The glycoprotein hormones exert their biological functions by interacting with their cognate GPCRs. Both LH and CG bind to the same receptor, the luteinizing hormone-choriogonadotropin receptor (LHCGR); FSH binds to FSH-R and TSH to TSH-R. GPHRs couple primarily to the G(s)-protein and promotes cAMP production, but also to the G(i)- or G(q)-protein.

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gi 1183154130   1 GCYIEGFFATLGGEIALWSLVVLAIERYVVVCKPMS-NFRFGENHA 45
Cdd:cd15136    79 GCKTAGFLAVFSSELSVFTLTVITLERWYAITHAMHlNKRLSLRQA 124

relaxin family peptide receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes relaxin/insulin-like family peptide receptor 1 (RXFP1 or LGR7) and 2 (RXFP2 or LGR8), which contain a very large extracellular N-terminal domain with numerous leucine-rich repeats responsible for hormone recognition and binding. Relaxin is a member of the insulin superfamily that has diverse actions in both reproductive and non-reproductive tissues. The relaxin-like peptide family includes relaxin-1, relaxin-2, and the insulin-like (INSL) peptides such as INSL3, INSL4, INSL5 and INSL6. The relaxin family peptides share high structural but low sequence similarity, and exert their physiological functions by activating a group of four GPCRs, RXFP1-4. Relaxin and INSL3 are the endogenous ligands for RXFP1 and RXFP2, respectively. Upon receptor binding, relaxin activates a variety of signaling pathways to produce second messengers such as cAMP.

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gi 1183154130   1 GCYIEGFFATLGGEIALWSLVVLAIERYVVVCKPMSNFRFGENHA 45
Cdd:cd15137    79 LCTFAGFLATLSSEVSVLILTLITLDRFICIVFPFSGRRLGLRRA 123

olfactory receptor family 4 and related proteins, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes human olfactory receptor family 4 and related proteins in other mammals, sauropsids, and amphibians. Olfactory receptors (ORs) play a central role in olfaction, the sense of smell. ORs belong to the class A rhodopsin-like family of G protein-coupled receptors and constitute the largest multigene family in mammals of approximately 1,000 genes. More than 60% of human ORs are non-functional pseudogenes compared to only 20% in mouse. Each OR can recognize structurally similar odorants, and a single odorant can be detected by several ORs. Binding of an odorant to the olfactory receptor induces a conformational change that leads to the activation of the olfactory-specific G protein (Golf). The G protein (Golf and/or Gs) in turn stimulates adenylate cyclase to make cAMP. The cAMP opens cyclic nucleotide-gated ion channels, which allow the influx of calcium and sodium ions, resulting in depolarization of the olfactory receptor neuron and triggering an action potential which transmits this information to the brain. A consensus nomenclature system based on evolutionary divergence is used here to classify the olfactory receptor family. The nomenclature begins with the root name OR, followed by an integer representing a family, a letter denoting a subfamily, and an integer representing the individual gene within the subfamily.

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gi 1183154130   1 GCYIEGFFATL--GGEIALwsLVVLAIERYVVVCKPM 35
Cdd:cd15226    72 GCMAQIFFLHFfgGSEMVL--LIAMAFDRYVAICKPL 106

glycoprotein hormone receptors and leucine-rich repeats containing G protein-coupled receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; This subfamily includes the glycoprotein hormone receptors (GPHRs), vertebrate receptors containing 17 leucine-rich repeats (LGR4-6), and the relaxin family peptide receptors (also known as LGR7 and LGR8). They are seven transmembrane domain receptors with a very large extracellular N-terminal domain containing many leucine-rich repeats responsible for hormone recognition and binding. The glycoprotein hormone receptor family contains receptors for the pituitary hormones, thyrotropin (thyroid-stimulating hormone receptor), follitropin (follicle-stimulating hormone receptor), and lutropin (luteinizing hormone receptor). Glycoprotein hormone receptors couple primarily to the G(s)-protein and promotes cAMP production, but also to the G(i)- or G(q)-protein. Two orphan GPCRs, LGR7 and LGR8, have been recently identified as receptors for the relaxin peptide hormones.

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gi 1183154130   1 GCYIEGFFATLGGEIALWSLVVLAIERYVVVCKPMSNFRFGENHA 45
Cdd:cd14980    80 PCLLACFLVSLSSLMSVLMMLLITLDRYICIVYPFSNKRLSYKSA 124