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 45645740   2 DYLQRIEQQKCMVSQDVSYQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:cd15331 143 DLDRVLKTGVCLISQDYGYTIFSTVGAFYVPLLLMIIIYWKIYQAA 188

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 45645740   2 DYLQRIEQQKCMVSQDVSYQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:cd15331 143 DLDRVLKTGVCLISQDYGYTIFSTVGAFYVPLLLMIIIYWKIYQAA 188

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 45645740   2 DYLQRIEQQKCMVSQDVSYQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:cd15331 143 DLDRVLKTGVCLISQDYGYTIFSTVGAFYVPLLLMIIIYWKIYQAA 188

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 45645740   8 EQQKCMVSQDVSYQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:cd15328 148 DSEECQVSQEPSYTVFSTFGAFYLPLCVVLFVYWKIYKAA 187

dopamine 1-like receptor 2 from Drosophila melanogaster and similar proteins, member of the class A family of seven-transmembrane G protein-coupled receptors; G protein-coupled dopamine 1-like receptor 2 is expressed in Drosophila heads and it shows significant sequence similarity with vertebrate and invertebrate dopamine receptors. Although the Drosophila Dop1R2 receptor does not cluster into the D1-like structural group, it does show pharmacological properties similar to D1-like receptors. As shown in vertebrate D1-like receptors, agonist stimulation of Dop1R2 activates adenylyl cyclase to increase cAMP levels and also generates a calcium signal through stimulation of phospholipase C.

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gi 45645740   9 QQKCMVSQDVSYQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:cd15067 149 PNQCLFTDDSGYLIFSSCVSFYIPLVVMLFTYYRIYRAA 187

serotonin receptor subtype 1E, 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 45645740  10 QKCMVSQD-VSYQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:cd15335 148 SQCIIQHDhVIYTIYSTFGAFYIPLTLILILYYRIYHAA 186

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.

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gi 45645740   6 RIEQQKCMVSQDVSYQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:cd15330 145 RSDPDACTISKDPGYTIYSTFGAFYIPLILMLVLYGRIFKAA 186

amine receptors and similar proteins, member of the class A family of seven-transmembrane G protein-coupled receptors; Amine receptors of the class A family of GPCRs include adrenoceptors, 5-HT (serotonin) receptors, muscarinic cholinergic receptors, dopamine receptors, histamine receptors, and trace amine receptors. The receptors of amine subfamily are major therapeutic targets for the treatment of neurological disorders and psychiatric diseases. 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 45645740  12 CMVSQDVSYQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:cd14967 151 CEFTPNKIYVLVSSVISFFIPLLIMIVLYARIFRVA 186

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 45645740    14 VSQDVSYQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:pfam00001 145 LSKPVSYTLLISVLGFLLPLLVILVCYTLIIRTL 178

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.

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gi 45645740  12 CMVSQDVSYQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:cd15055 155 CVVVVNFIWGVVDLVLTFILPCTVMIVLYMRIFVVA 190

alpha-2 adrenergic receptors, 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. 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 45645740  11 KCMVSQDVSYQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:cd15059 151 QCELSDDPGYVLFSSIGSFYIPLLIMIIVYARIYRAA 187

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 45645740  12 CMVSQDVSYQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:cd15325 150 CQITEEPGYALFSALGSFYLPLAIILVMYCRVYVVA 185

beta adrenergic receptors (adrenoceptors), member of the class A family of seven-transmembrane G protein-coupled receptors; The beta adrenergic receptor (beta adrenoceptor), also known as beta AR, is activated by hormone adrenaline (epinephrine) and plays important roles in regulating cardiac function and heart rate, as well as pulmonary physiology. 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 beta-ARs can lead to cardiac dysfunction such as arrhythmias or heart failure. 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 45645740  20 YQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:cd15058 166 YAIASSVVSFYIPLLIMIFVYARVFLIA 193

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.

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gi 45645740   6 RIEQQKCMVSQDVSYQVFATCCTFYVPLLVILALYWKIYQTA 47
Cdd:cd15057 153 YADPCQCDSSLNRTYAISSSLISFYIPVAIMIVTYTRIYRIA 194