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 62087838   6 QAVCDCISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15054 227 QAVCDCVSPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 267

serotonin receptor subtype 6, member of the class A family of seven-transmembrane G protein-coupled receptors; The 5-HT6 receptors are a subfamily of serotonin receptors that bind the neurotransmitter serotonin (5HT; 5-hydroxytryptamine) in the mammalian central nervous system (CNS). 5-HT6 receptors are selectively linked to G proteins of the G(s) family, which positively stimulate adenylate cyclase, causing cAMP formation and activation of protein kinase A. The 5-HT6 receptors mediates excitatory neurotransmission and are involved in learning and memory; thus they are promising targets for the treatment of cognitive impairment. 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.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|.
gi 62087838   6 QAVCDCISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15054 227 QAVCDCVSPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 267

serotonin receptor subtype 6, member of the class A family of seven-transmembrane G protein-coupled receptors; The 5-HT6 receptors are a subfamily of serotonin receptors that bind the neurotransmitter serotonin (5HT; 5-hydroxytryptamine) in the mammalian central nervous system (CNS). 5-HT6 receptors are selectively linked to G proteins of the G(s) family, which positively stimulate adenylate cyclase, causing cAMP formation and activation of protein kinase A. The 5-HT6 receptors mediates excitatory neurotransmission and are involved in learning and memory; thus they are promising targets for the treatment of cognitive impairment. 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.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|.
gi 62087838   6 QAVCDCISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15054 227 QAVCDCVSPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 267

serotonin receptor subtypes B1 and B2 from Aplysia californica and similar proteins; member of the class A family of seven-transmembrane G protein-coupled receptors; This subfamily includes Aplysia californica serotonin receptors Ap5-HTB1 and Ap5-HTB2, and similar proteins from bilateria including insects, mollusks, annelids, and worms. Ap5-HTB1 is one of the several different receptors for 5-hydroxytryptamine (5HT, serotonin). In Aplysia, serotonin plays important roles in a variety of behavioral and physiological processes mediated by the central nervous system. These include circadian clock, feeding, locomotor movement, cognition and memory, synaptic growth and synaptic plasticity. Both Ap5-HTB1 and Ap5-HTB2 receptors are coupled to G-proteins that stimulate phospholipase C, leading to the activation of phosphoinositide metabolism. Ap5-HTB1 is expressed in the reproductive system, whereas Ap5-HTB2 is expressed in the central nervous system.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*.
gi 62087838   1 CIPSPQAVCD-CISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRA 45
Cdd:cd15065 254 IINIIAAFCKtCIPPKCFKILTWLGYFNSCLNPIIYSIFNSEFRRA 299

octopamine receptors in invertebrates, member of the class A family of seven-transmembrane G protein-coupled receptors; G-protein coupled receptor for octopamine (OA), which functions as a neurotransmitter, neurohormone, and neuromodulator in invertebrate nervous system. Octopamine (also known as beta, 4-dihydroxyphenethylamine) is an endogenous trace amine that is highly similar to norepinephrine, but lacks a hydroxyl group, and has effects on the adrenergic and dopaminergic nervous systems. Based on the pharmacological and signaling profiles, the octopamine receptors can be classified into at least two groups: OA1 receptors elevate intracellular calcium levels in muscle, whereas OA2 receptors activate adenylate cyclase and increase cAMP production.

                        10        20        30
                ....*....|....*....|....*....|....*.
gi 62087838  10 DCISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRA 45
Cdd:cd15063 230 DCIPPLLFSVFFWLGYCNSALNPCIYALFSRDFRFA 265

trace amine-associated receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; The trace amine-associated receptors (TAARs) are a distinct subfamily within the class A G protein-coupled receptor family. Trace amines are endogenous amines of unknown function that have strong structural and metabolic similarity to classical monoamine neurotransmitters (serotonin, noradrenaline, adrenaline, dopamine, and histamine), which play critical roles in human and animal physiological activities such as cognition, consciousness, mood, motivation, perception, and autonomic responses. However, trace amines are found in the mammalian brain at very low concentrations compared to classical monoamines. Trace amines, including p-tyramine, beta-phenylethylamine, and tryptamine, are also thought to act as chemical messengers to exert their biological effects in vertebrates. 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.

                        10        20        30
                ....*....|....*....|....*....|....*
gi 62087838  12 ISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15055 251 TPSSVFDVLIWLGYFNSCLNPLIYALFYPWFRKAL 285

alpha-2 adrenergic receptors subtype A, member of the class A family of seven-transmembrane G protein-coupled receptors; The alpha-2 adrenergic receptors (or adrenoceptors) are a subfamily of the class A rhodopsin-like GPCRs that share a common architecture of seven transmembrane helices. This subfamily consists of three highly homologous receptor subtypes that have a key role in neurotransmitter release: alpha-2A, alpha-2B, and alpha-2C. In addition, a fourth subtype, alpha-2D is present in ray-finned fishes and amphibians, but is not found in humans. The alpha-2 receptors are found in both central and peripheral nervous system and serve to produce inhibitory functions through the G(i) proteins. Thus, the alpha-2 receptors inhibit adenylate cyclase, which decreases cAMP production and thereby decreases calcium influx during the action potential. Consequently, lowered levels of calcium will lead to a decrease in neurotransmitter release by negative feedback.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|.
gi 62087838   7 AVCDCISPG-LFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15322 219 AVCDCSVPEtLFKFFFWFGYCNSSLNPVIYTIFNHDFRRAF 259

D1-like family of dopamine receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; Dopamine receptors are members of the class A G protein-coupled receptors that are involved in many neurological processes in the central nervous system (CNS). The neurotransmitter dopamine is the primary endogenous agonist for dopamine receptors. Dopamine receptors consist of at least five subtypes: D1, D2, D3, D4, and D5. The D1 and D5 subtypes are members of the D1-like family of dopamine receptors, whereas the D2, D3 and D4 subtypes are members of the D2-like family. The D1-like family receptors are coupled to G proteins of the G(s) family, which activate adenylate cyclase, causing cAMP formation and activation of protein kinase A. In contrast, activation of D2-like family receptors is linked to G proteins of the G(i) family, which inhibit adenylate cyclase. Dopamine receptors are major therapeutic targets for neurological and psychiatric disorders such as drug abuse, depression, schizophrenia, or Parkinson's disease. 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.

                        10        20        30
                ....*....|....*....|....*....|....*
gi 62087838  11 CISPGLFDVLTWLGYCNSTMNPIIYPlFMRDFKRA 45
Cdd:cd15057 265 CVPDTTFIVFVWLGWANSSLNPIIYA-FNADFRKA 298

D2-like dopamine receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; Dopamine receptors are members of the class A G protein-coupled receptors that are involved in many neurological processes in the central nervous system (CNS). The neurotransmitter dopamine is the primary endogenous agonist for dopamine receptors. Dopamine receptors consist of at least five subtypes: D1, D2, D3, D4, and D5. The D1 and D5 subtypes are members of the D1-like family of dopamine receptors, whereas the D2, D3 and D4 subtypes are members of the D2-like family. The D1-like family receptors are coupled to G proteins of the G(s) family, which activate adenylate cyclase, causing cAMP formation and activation of protein kinase A. In contrast, activation of D2-like family receptors is linked to G proteins of the G(i) family, which inhibit adenylate cyclase. Dopamine receptors are major therapeutic targets for neurological and psychiatric disorders such as drug abuse, depression, schizophrenia, or Parkinson's disease.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*
gi 62087838   1 CIPSPQAVCdCISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRA 45
Cdd:cd15053 219 CPKLQNQSC-HVGPALFSLTTWLGYVNSFLNPIIYTIFNIEFRKA 262

trace amine-associated receptor 1 and similar receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; The trace amine-associated receptor 1 (TAAR1) is one of the 15 identified trace amine-associated receptor subtypes, which form a distinct subfamily within the class A G protein-coupled receptor family. Trace amines are endogenous amines of unknown function that have strong structural and metabolic similarity to classical monoamine neurotransmitters (serotonin, noradrenaline, adrenaline, dopamine, and histamine), which play critical roles in human and animal physiological activities such as cognition, consciousness, mood, motivation, perception, and autonomic responses. However, trace amines are found in the mammalian brain at very low concentrations compared to classical monoamines. TAAR1 is coupled to the Gs protein, which leads to activation of adenylate cyclase, and is thought to play functional role in the regulation of brain monoamines. TAAR1 is also shown to be activated by psychoactive compounds such as Ecstasy (MDMA), amphetamine and LSD. 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.

                        10        20        30
                ....*....|....*....|....*....|....*
gi 62087838  12 ISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15314 248 IPPVLIEVLNWLGYSNSTLNPFIYAFFYSWFRKAF 282

histamine subtype H2 receptor, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes histamine receptor subtype H2R, a member of histamine receptor family, which belongs to the class A of GPCRs. Histamine plays a key role as chemical mediator and neurotransmitter in various physiological and pathophysiological processes in the central and peripheral nervous system. Histamine exerts its functions by binding to four different G protein-coupled receptors (H1-H4). The H2R subtype selectively interacts with the G(s)-type G protein that activates adenylate cyclase, leading to increased cAMP production and activation of Protein Kinase A. H2R is found in various tissues such as the brain, stomach, and heart. Its most prominent role is in histamine-induced gastric acid secretion. 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.

                        10        20        30
                ....*....|....*....|....*....|....*..
gi 62087838  10 DCISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15051 251 DNINETALSVVLWLGYANSALNPILYAFLNRDFRRAF 287

trace amine-associated receptors 2, 3, 4, and similar receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; TAAR2, TAAR3, and TAAR4 are among the 15 identified trace amine-associated receptor subtypes, which form a distinct subfamily within the class A G protein-coupled receptor family. Trace amines are endogenous amines of unknown function that have strong structural and metabolic similarity to classical monoamine neurotransmitters (serotonin, noradrenaline, adrenaline, dopamine, and histamine), which play critical roles in human and animal physiological activities such as cognition, consciousness, mood, motivation, perception, and autonomic responses. However, trace amines are found in the mammalian brain at very low concentrations compared to classical monoamines. Trace amines, including p-tyramine, beta-phenylethylamine, and tryptamine, are also thought to act as chemical messengers to exert their biological effects in vertebrates. 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.

                        10        20        30
                ....*....|....*....|....*....|..
gi 62087838  15 GLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15312 258 DLFDALVWLGYFNSTCNPLIYGFFYPWFQKAF 289

D3 subtype of the D2-like family of dopamine receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; Dopamine receptors are members of the class A G protein-coupled receptors that are involved in many neurological processes in the central nervous system (CNS). The neurotransmitter dopamine is the primary endogenous agonist for dopamine receptors. Dopamine receptors consist of at least five subtypes: D1, D2, D3, D4, and D5. The D1 and D5 subtypes are members of the D1-like family of dopamine receptors, whereas the D2, D3 and D4 subtypes are members of the D2-like family. Activation of D2-like family receptors is linked to G proteins of the G(i) family. This leads to a decrease in adenylate cyclase activity, thereby decreasing cAMP levels. Dopamine receptors are major therapeutic targets for neurological and psychiatric disorders such as drug abuse, depression, schizophrenia, or Parkinson's disease.

                        10        20        30
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gi 62087838  12 ISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15310 225 VPPELYSATTWLGYVNSALNPVIYTTFNIEFRRAF 259

tyramine/octopamine receptor-like, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes tyramine/octopamine receptors and similar proteins found in insects and other invertebrates. Both octopamine and tyramine mediate their actions via G protein-coupled receptors (GPCRs) and are the invertebrate equivalent of vertebrate adrenergic neurotransmitters. In Drosophila, octopamine is involved in ovulation by mediating an egg release from the ovary, while a physiological role for tyramine in this process is not fully understood. 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.

                        10        20        30
                ....*....|....*....|....*....|....*
gi 62087838  11 CISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRA 45
Cdd:cd15060 225 SPSAKVVNFITWLGYVNSALNPVIYTIFNLDFRRA 259

D1A (or D1) subtype dopamine receptor, member of the class A family of seven-transmembrane G protein-coupled receptors; Dopamine receptors are members of the class A G protein-coupled receptors that are involved in many neurological processes in the central nervous system (CNS). The neurotransmitter dopamine is the primary endogenous agonist for dopamine receptors. Dopamine receptors consist of at least five subtypes: D1, D2, D3, D4, and D5. The D1 and D5 subtypes are members of the D1-like family of dopamine receptors, whereas the D2, D3 and D4 subtypes are members of the D2-like family. The D1-like family receptors are coupled to G proteins of the G(s) family, which activate adenylate cyclase, causing cAMP formation and activation of protein kinase A. Dopamine receptors are major therapeutic targets for neurological and psychiatric disorders such as drug abuse, depression, schizophrenia, or Parkinson's disease.

                        10        20        30
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gi 62087838  11 CISPGLFDVLTWLGYCNSTMNPIIYPlFMRDFKRAL 46
Cdd:cd15320 285 CISSTTFDVFVWFGWANSSLNPIIYA-FNADFRKAF 319

serotonin receptor subtype 1A from invertebrates, member of the class A family of seven-transmembrane G protein-coupled receptors; The 5-HT1 receptors, one of 14 mammalian 5-HT receptors, is a member of the class A of GPCRs and is activated by the endogenous neurotransmitter and peripheral signal mediator serotonin (5-hydroxytryptamine, 5-HT). The 5-HT1 receptors mediate inhibitory neurotransmission by coupling to G proteins of the G(i/o) family, which lead to a decrease in adenylate cyclase activity, thereby decreasing intracellular cAMP levels and calcium influx. The 5-HT1 receptor subfamily includes 5 subtypes: 5-HT1A, 5-HT1B, 5-HT1D, 5-HT1E, and 5-HT1F. There is no 5-HT1C receptor subtype, as it has been reclassified as the 5-HT2C receptor. In the CNS, serotonin is involved in the regulation of appetite, mood, sleep, cognition, learning and memory, as well as implicated in neurologic disorders such as migraine, schizophrenia, and depression.

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gi 62087838   4 SPQAVCDCISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRA 45
Cdd:cd15331 219 MPFCGAWQISRFLESFFLWLGYFNSLLNPIIYTIFSPDFRGA 260

neuropeptide FF receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; Neuropeptide FF (NPFF) is a mammalian octapeptide that belongs to a family of neuropeptides containing an RF-amide motif at their C-terminus that have been implicated in a wide range of physiological functions in the brain including pain sensitivity, insulin release, food intake, memory, blood pressure, and opioid-induced tolerance and hyperalgesia. The effects of these peptides are mediated through neuropeptide FF1 and FF2 receptors (NPFF1-R and NPFF2-R) which are predominantly expressed in the brain. NPFF induces pro-nociceptive effects, mainly through the NPFF1-R, and anti-nociceptive effects, mainly through the NPFF2-R. NPFF has been shown to inhibit adenylate cyclase via the Gi protein coupled to NPFF1-R.

                        10        20
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gi 62087838  22 WLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15207 267 WLAYFNSCVNPIVYGYFNRNFRKGF 291

alpha-1 adrenergic receptors subtype D, member of the class A family of seven-transmembrane G protein-coupled receptors; The alpha-1 adrenergic receptors (or adrenoceptors) are a subfamily of the class A rhodopsin-like GPCRs that share a common architecture of seven transmembrane helices. This subfamily consists of three highly homologous receptor subtypes that primarily mediate smooth muscle contraction: alpha-1A, alpha-1B, and alpha-1D. Activation of alpha-1 receptors by catecholamines such as norepinephrine and epinephrine couples to the G(q) protein, which then activates the phospholipase C pathway, leading to an increase in IP3 and calcium. Consequently, the elevation of intracellular calcium concentration leads to vasoconstriction in smooth muscle of blood vessels. In addition, activation of alpha-1 receptors by phenylpropanolamine (PPA) produces anorexia and may induce appetite suppression in rats.

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gi 62087838  13 SPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15327 228 SEMVFKVIFWLGYFNSCVNPIIYPCSSKEFKRAF 261

serotonin receptor subtype 1A from vertebrates, member of the class A family of seven-transmembrane G protein-coupled receptors; The 5-HT1 receptors, one of 14 mammalian 5-HT receptors, is a member of the class A of GPCRs and is activated by the endogenous neurotransmitter and peripheral signal mediator serotonin (5-hydroxytryptamine, 5-HT). The 5-HT1 receptors mediate inhibitory neurotransmission by coupling to G proteins of the G(i/o) family, which lead to a decrease in adenylate cyclase activity, thereby decreasing intracellular cAMP levels and calcium influx. The 5-HT1 receptor subfamily includes 5 subtypes: 5-HT1A, 5-HT1B, 5-HT1D, 5-HT1E, and 5-HT1F. There is no 5-HT1C receptor subtype, as it has been reclassified as the 5-HT2C receptor. In the CNS, serotonin is involved in the regulation of appetite, mood, sleep, cognition, learning and memory, as well as implicated in neurologic disorders such as migraine, schizophrenia, and depression.

                        10        20        30
                ....*....|....*....|....*....|.
gi 62087838  16 LFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15330 230 LGAIINWLGYSNSLLNPIIYAYFNKDFQSAF 260

histamine receptor subtypes H3R and H4R, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes histamine subtypes H3R and H4R, members of the histamine receptor family, which belong to the class A of GPCRs. Histamine plays a key role as chemical mediator and neurotransmitter in various physiological and pathophysiological processes in the central and peripheral nervous system. Histamine exerts its functions by binding to four different G protein-coupled receptors (H1-H4). The H3 and H4 receptors couple to the G(i)-proteins, which leading to the inhibition of cAMP formation. The H3R receptor functions as a presynaptic autoreceptors controlling histamine release and synthesis. The H4R plays an important role in histamine-mediated chemotaxis in mast cells and eosinophils. 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.

                        10        20        30        40
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gi 62087838   6 QAVCD--CISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRA 45
Cdd:cd15048 254 RSFCSgsCVDSYLYEFTFWLLWTNSAINPFLYAACHPRFRKA 295

D2 subtype of the D2-like family of dopamine receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; Dopamine receptors are members of the class A G protein-coupled receptors that are involved in many neurological processes in the central nervous system (CNS). The neurotransmitter dopamine is the primary endogenous agonist for dopamine receptors. Dopamine receptors consist of at least five subtypes: D1, D2, D3, D4, and D5. The D1 and D5 subtypes are members of the D1-like family of dopamine receptors, whereas the D2, D3 and D4 subtypes are members of the D2-like family. Activation of D2-like family receptors is linked to G proteins of the G(i) family. This leads to a decrease in adenylate cyclase activity, thereby decreasing cAMP levels. Dopamine receptors are major therapeutic targets for neurological and psychiatric disorders such as drug abuse, depression, schizophrenia, or Parkinson's disease.

                        10        20        30
                ....*....|....*....|....*....|....*....
gi 62087838   9 CDC-ISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15309 216 CDCnIPPALYSAFTWLGYVNSAVNPIIYTTFNIEFRKAF 254

trace amine-associated receptor 5 and similar receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; Included in this group are mammalian TAAR5, TAAR6, TAAR8, TAAR9, and similar proteins. They are among the 15 identified trace amine-associated receptors (TAARs), a distinct subfamily within the class A G protein-coupled receptors. Trace amines are endogenous amines of unknown function that have strong structural and metabolic similarity to classical monoamine neurotransmitters (serotonin, noradrenaline, adrenaline, dopamine, and histamine), which play critical roles in human and animal physiological activities such as cognition, consciousness, mood, motivation, perception, and autonomic responses. However, trace amines are found in the mammalian brain at very low concentrations compared to classical monoamines. Trace amines, including p-tyramine, beta-phenylethylamine, and tryptamine, are also thought to act as chemical messengers to exert their biological effects in vertebrates. 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.

                        10        20        30
                ....*....|....*....|....*....|....*.
gi 62087838  12 ISPGL-FDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15317 255 ITPAIvFDAVIWLGYFNSAFNPFIYAFFYPWFRKAF 290

serotonin receptor subtype 2B, member of the class A family of seven-transmembrane G protein-coupled receptors; The 5-HT2 receptors are a subfamily of serotonin receptors that bind the neurotransmitter serotonin (5HT; 5-hydroxytryptamine) in the central nervous system (CNS). The 5-HT2 subfamily is composed of three subtypes that mediate excitatory neurotransmission: 5-HT2A, 5-HT2B, and 5-HT2C. They are selectively linked to G proteins of the G(q/11) family and activate phospholipase C, which leads to activation of protein kinase C and calcium release. In the CNS, serotonin is involved in the regulation of appetite, mood, sleep, cognition, learning and memory, as well as implicated in diseases such as migraine, schizophrenia, and depression. Indeed, 5-HT2 receptors are attractive targets for a variety of psychoactive drugs, ranging from atypical antipsychotic drugs, antidepressants, and anxiolytics, which have an antagonistic action on 5-HT2 receptors, to hallucinogens, which act as agonists at postsynaptic 5-HT2 receptors. 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.

                        10        20        30
                ....*....|....*....|....*....|....*..
gi 62087838  16 LFDVLTWLGYCNSTMNPIIYPLFMRDFKRALGRFLPC 52
Cdd:cd15306 240 LMEIFVWIGYVSSGVNPLVYTLFNKTFRDAFGRYITC 276

serotonin receptor subtype 4, member of the class A family of seven-transmembrane G protein-coupled receptors; The 5-HT4 subtype is a member of the serotonin receptor family that belongs to the class A G protein-coupled receptors, and binds the neurotransmitter serotonin (5HT; 5-hydroxytryptamine) in the mammalian central nervous system (CNS). 5-HT4 receptors are selectively linked to G proteins of the G(s) family, which positively stimulate adenylate cyclase, causing cAMP formation and activation of protein kinase A. 5-HT4 receptor-specific agonists have been shown to enhance learning and memory in animal studies. Moreover, hippocampal 5-HT4 receptor expression has been reported to be inversely correlated with memory performance in humans. 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.

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gi 62087838  22 WLGYCNSTMNPIIYPLFMRDFKRA 45
Cdd:cd15056 270 WLGYINSGLNPFLYAFFNKSFRRA 293

alpha-1 adrenergic receptors subtype A, member of the class A family of seven-transmembrane G protein-coupled receptors; The alpha-1 adrenergic receptors (or adrenoceptors) are a subfamily of the class A rhodopsin-like GPCRs that share a common architecture of seven transmembrane helices. This subfamily consists of three highly homologous receptor subtypes that primarily mediate smooth muscle contraction: alpha-1A, alpha-1B, and alpha-1D. Activation of alpha-1 receptors by catecholamines such as norepinephrine and epinephrine couples to the G(q) protein, which then activates the phospholipase C pathway, leading to an increase in IP3 and calcium. Consequently, the elevation of intracellular calcium concentration leads to vasoconstriction in smooth muscle of blood vessels. In addition, activation of alpha-1 receptors by phenylpropanolamine (PPA) produces anorexia and may induce appetite suppression in rats.

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gi 62087838  13 SPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15325 228 SDTVFKITFWLGYFNSCINPIIYPCSSQEFKKAF 261

cholecystokinin receptors and related proteins, member of the class A family of seven-transmembrane G protein-coupled receptors; This group represents four G-protein coupled receptors that are members of the RFamide receptor family, including cholecystokinin receptors (CCK-AR and CCK-BR), orexin receptors (OXR), neuropeptide FF receptors (NPFFR), and pyroglutamylated RFamide peptide receptor (QRFPR). These RFamide receptors are activated by their endogenous peptide ligands that share a common C-terminal arginine (R) and an amidated phenylanine (F) motif. CCK-AR (type A, alimentary; also known as CCK1R) is found abundantly on pancreatic acinar cells and binds only sulfated CCK-peptides with very high affinity, whereas CCK-BR (type B, brain; also known as CCK2R), the predominant form in the brain and stomach, binds CCK or gastrin and discriminates poorly between sulfated and non-sulfated peptides. CCK is implicated in regulation of digestion, appetite control, and body weight, and is involved in neurogenesis via CCK-AR. There is some evidence to support that CCK and gastrin, via their receptors, are involved in promoting cancer development and progression, acting as growth and invasion factors. Orexins (OXs; also referred to as hypocretins) are neuropeptide hormones that regulate the sleep-wake cycle and potently influence homeostatic systems regulating appetite and feeding behavior or modulating emotional responses such as anxiety or panic. OXs are synthesized as prepro-orexin (PPO) in the hypothalamus and then proteolytically cleaved into two forms of isoforms: orexin-A (OX-A) and orexin-B (OX-B). OXA is a 33 amino-acid peptide with N-terminal pyroglutamyl residue and two intramolecular disulfide bonds, whereas OXB is a 28 amino-acid linear peptide with no disulfide bonds. OX-A binds orexin receptor 1 (OX1R) with high-affinity, but also binds with somewhat low-affinity to OX2R, and signals primarily to Gq coupling, whereas OX-B shows a strong preference for the orexin receptor 2 (OX2R) and signals through Gq or Gi/o coupling. The 26RFa, also known as QRFP (Pyroglutamylated RFamide peptide), is a 26-amino acid residue peptide that exerts similar orexigenic activity including the regulation of feeding behavior in mammals. It is the ligand for G-protein coupled receptor 103 (GPR103), which is predominantly expressed in paraventricular (PVN) and ventromedial (VMH) nuclei of the hypothalamus. GPR103 shares significant protein sequence homology with orexin receptors (OX1R and OX2R), which have recently shown to produce a neuroprotective effect in Alzheimer's disease by forming a functional heterodimer with GPR103. Neuropeptide FF (NPFF) is a mammalian octapeptide that has been implicated in a wide range of physiological functions in the brain including pain sensitivity, insulin release, food intake, memory, blood pressure, and opioid-induced tolerance and hyperalgesia. The effects of NPFF are mediated through neuropeptide FF1 and FF2 receptors (NPFF1-R and NPFF2-R) which are predominantly expressed in the brain. NPFF induces pro-nociceptive effects, mainly through the NPFF1-R, and anti-nociceptive effects, mainly through the NPFF2-R.

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gi 62087838  12 ISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd14993 262 NFLLILPFAQLLGYSNSAINPIIYCFMSKKFRRGF 296

trace amine-associated receptor 5, member of the class A family of seven-transmembrane G protein-coupled receptors; The trace amine-associated receptor 5 is one of the 15 identified amine-activated G protein-coupled receptors (TAARs), a distinct subfamily within the class A G protein-coupled receptors. Trace amines are endogenous amines of unknown function that have strong structural and metabolic similarity to classical monoamine neurotransmitters (serotonin, noradrenaline, adrenaline, dopamine, and histamine), which play critical roles in human and animal physiological activities such as cognition, consciousness, mood, motivation, perception, and autonomic responses. However, trace amines are found in the mammalian brain at very low concentrations compared to classical monoamines. Trace amines, including p-tyramine, beta-phenylethylamine, and tryptamine, are also thought to act as chemical messengers to exert their biological effects in vertebrates. 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.

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gi 62087838  14 PGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15318 250 PLLFDIIIWFAYFNSACNPLIYVFSYPWFRKAL 282

serotonin receptor subtype 5, member of the class A family of seven-transmembrane G protein-coupled receptors; 5-HT5 receptor, one of 14 mammalian 5-HT receptors, is activated by the neurotransmitter and peripheral signal mediator serotonin (also known as 5-hydroxytryptamine or 5-HT). The 5-HT5A and 5-HT5B receptors have been cloned from rat and mouse, but only the 5-HT5A isoform has been identified in human because of the presence of premature stop codons in the human 5-HT5B gene, which prevents a functional receptor from being expressed. 5-HT5 receptors mediate inhibitory neurotransmission by coupling to G proteins of the G(i/0) family, which lead to a decrease in adenylate cyclase activity, thereby decreasing intracellular cAMP levels and calcium influx. In the CNS, serotonin is involved in the regulation of appetite, mood, sleep, cognition, learning and memory, as well as implicated in neurologic disorders such as migraine, schizophrenia, and depression.

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gi 62087838   4 SPQAVCDcISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15328 218 SPLCSCD-IPPIWKSIFLWLGYSNSFFNPLIYTAFNKNYNNAF 259

muscarinic acetylcholine receptor DM1, member of the class A family of seven-transmembrane G protein-coupled receptors; This subgroup includes muscarinic acetylcholine receptor DM1-like from invertebrates. Muscarinic acetylcholine receptors (mAChRs) regulate the activity of many fundamental central and peripheral functions. The mAChR family consists of 5 subtypes M1-M5, which can be further divided into two major groups according to their G-protein coupling preference. The M1, M3 and M5 receptors selectively interact with G proteins of the G(q/11) family, whereas the M2 and M4 receptors preferentially link to the G(i/o) types of G proteins. Activation of mAChRs by agonist (acetylcholine) leads to a variety of biochemical and electrophysiological responses. In general, the exact nature of these responses and the subsequent physiological effects mainly depend on the molecular and pharmacological identity of the activated receptor subtype(s). 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.

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gi 62087838   1 CIPSPQAVCDCISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKR 44
Cdd:cd15301 225 LIKAFFPCSDTIPTELWDFSYYLCYINSTINPLCYALCNAAFRR 268

muscarinic acetylcholine receptor subtype M3, member of the class A family of seven-transmembrane G protein-coupled receptors; Muscarinic acetylcholine receptors (mAChRs) regulate the activity of many fundamental central and peripheral functions. The mAChR family consists of 5 subtypes M1-M5, which can be further divided into two major groups according to their G-protein coupling preference. The M1, M3 and M5 receptors selectively interact with G proteins of the G(q/11) family, whereas the M2 and M4 receptors preferentially link to the G(i/o) types of G proteins. The M3 receptor is mainly located in smooth muscle, exocrine glands and vascular endothelium. It induces vomiting in the central nervous system and is a critical regulator of glucose homeostasis by modulating insulin secretion. Generally, M3 receptor causes contraction of smooth muscle resulting in vasoconstriction and increased glandular secretion. 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.

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gi 62087838  10 DCISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRALGRFLPCpRC 55
Cdd:cd15299 229 SCIPKTYWNLGYWLCYINSTVNPVCYALCNKTFRTTFKMLLLC-QC 273

7 transmembrane receptor (rhodopsin family); This family contains, amongst other G-protein-coupled receptors (GCPRs), members of the opsin family, which have been considered to be typical members of the rhodopsin superfamily. They share several motifs, mainly the seven transmembrane helices, GCPRs of the rhodopsin superfamily. All opsins bind a chromophore, such as 11-cis-retinal. The function of most opsins other than the photoisomerases is split into two steps: light absorption and G-protein activation. Photoisomerases, on the other hand, are not coupled to G-proteins - they are thought to generate and supply the chromophore that is used by visual opsins.

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gi 62087838     9 CDCISPGLFDVLTWLGYCNSTMNPIIY 35
Cdd:pfam00001 230 LSRLLDKALSVTLWLAYVNSCLNPIIY 256

beta-1 adrenergic receptors (adrenoceptors), member of the class A family of seven-transmembrane G protein-coupled receptors; The beta-1 adrenergic receptor (beta-1 adrenoceptor), also known as beta-1 AR, is activated by adrenaline (epinephrine) and plays important roles in regulating cardiac function and heart rate. The human heart contains three subtypes of the beta AR: beta-1 AR, beta-2 AR, and beta-3 AR. Beta-1 AR and beta-2 AR, which expressed at about a ratio of 70:30, are the major subtypes involved in modulating cardiac contractility and heart rate by positively stimulating the G(s) protein-adenylate cyclase-cAMP-PKA signaling pathway. In contrast, beta-3 AR produces negative inotropic effects by activating inhibitory G(i) proteins. The aberrant expression of betrayers can lead to cardiac dysfunction such as arrhythmias or heart failure.

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gi 62087838  10 DCISPGLFDVLTWLGYCNSTMNPIIY---PLFMRDF 42
Cdd:cd15958 263 ELVPDWLFVFFNWLGYANSAFNPIIYcrsPDFRKAF 298

G protein-coupled receptor 119, also called glucose-dependent insulinotropic receptor, member of the class A family of seven-transmembrane G protein-coupled receptors; GPR119 is activated by oleoylethanolamide (OEA), a naturally occurring bioactive lipid with hypophagic and anti-obesity effects. Immunohistochemistry and double-immunofluorescence studies revealed the predominant GPR119 localization in pancreatic polypeptide (PP)-cells of islets. In addition, GPR119 expression is elevated in islets of obese hyperglycemic mice as compared to control islets, suggesting a possible involvement of this receptor in the development of obesity and diabetes. GPR119 has a significant sequence similarity with the members of the endothelial differentiation gene family. 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.

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gi 62087838   6 QAVCD--CISPGLFDVLTWLGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd15104 241 QALCDecKLYDVLEDYLWLLGLCNSLLNPWIYAFWQKEVRRAL 283

adenosine receptor subfamily, member of the class A family of seven-transmembrane G protein-coupled receptors; The adenosine receptors (or P1 receptors), a family of G protein-coupled purinergic receptors, bind adenosine as their endogenous ligand. There are four types of adenosine receptors in human, designated as A1, A2A, A2B, and A3. Each type is encoded by a different gene and has distinct functions with some overlap. For example, both A1 and A2A receptors are involved in regulating myocardial oxygen consumption and coronary blood flow in the heart, while the A2A receptor also has a broad spectrum of anti-inflammatory effects in the body. These two receptors also expressed in the brain, where they have important roles in the release of other neurotransmitters such as dopamine and glutamate, while the A2B and A3 receptors found primarily in the periphery and play important roles in inflammation and immune responses. The A1 and A3 receptors preferentially interact with G proteins of the G(i/o) family, thereby lowering the intracellular cAMP levels, whereas the A2A and A2B receptors interact with G proteins of the G(s) family, activating adenylate cyclase to elevate cAMP levels.

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gi 62087838  23 LGYCNSTMNPIIYPLFMRDFKRAL 46
Cdd:cd14968 262 LSHANSAVNPIVYAYRIRKFRQTF 285