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 1934150654  54 NWPALSIVIIIIMTIGGNILVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYVWPLPRYLCPVWISL 133
Cdd:cd15305     1 NWPALLILIIIILTIGGNILVIMAVSLEKKLQNATNFFLMSLAVADMLVGILVMPVSLIAILYDYAWPLPRYLCPIWISL 80

                          90       100
                  ....*....|....*....|..
gi 1934150654 134 DVLFSTASIMHLCAISLDRCIS 155
Cdd:cd15305    81 DVLFSTASIMHLCAISLDRYVA 102

serotonin receptor subtype 2C, 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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  54 NWPALSIVIIIIMTIGGNILVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYVWPLPRYLCPVWISL 133
Cdd:cd15305     1 NWPALLILIIIILTIGGNILVIMAVSLEKKLQNATNFFLMSLAVADMLVGILVMPVSLIAILYDYAWPLPRYLCPIWISL 80

                          90       100
                  ....*....|....*....|..
gi 1934150654 134 DVLFSTASIMHLCAISLDRCIS 155
Cdd:cd15305    81 DVLFSTASIMHLCAISLDRYVA 102

serotonin receptor subtype 2C, 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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  54 NWPALSIVIIIIMTIGGNILVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYVWPLPRYLCPVWISL 133
Cdd:cd15305     1 NWPALLILIIIILTIGGNILVIMAVSLEKKLQNATNFFLMSLAVADMLVGILVMPVSLIAILYDYAWPLPRYLCPIWISL 80

                          90       100
                  ....*....|....*....|..
gi 1934150654 134 DVLFSTASIMHLCAISLDRCIS 155
Cdd:cd15305    81 DVLFSTASIMHLCAISLDRYVA 102

serotonin receptor subtype 2A, 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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  54 NWPALSIVIIIIMTIGGNILVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYVWPLPRYLCPVWISL 133
Cdd:cd15304     1 NWPALLTVIVIILTIAGNILVIMAVSLEKKLQNATNYFLMSLAIADMLLGFLVMPVSMLTILYGYRWPLPSKLCAVWIYL 80

                          90       100
                  ....*....|....*....|..
gi 1934150654 134 DVLFSTASIMHLCAISLDRCIS 155
Cdd:cd15304    81 DVLFSTASIMHLCAISLDRYIA 102

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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd14967    19 LVILAVYRNRRLRTVTNYFIVSLAVADLLVALLVMPFSAVYTLLGY-WPFGPVLCRFWIALDVLCCTASILNLCAISLDR 97

                  ....*..
gi 1934150654 153 CIS-SYP 158
Cdd:cd14967    98 YLAiTRP 104

serotonin receptor subtypes 1, 5 and 7, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes serotonin receptor subtypes 1, 5, and 7 that are activated by the neurotransmitter serotonin. The 5-HT1 and 5-HT5 receptors mediate inhibitory neurotransmission by coupling to G proteins of the G(i/o) family. The 5-HT1 receptor subfamily includes 5-HT1A, 5-HT1B, 5-HT1D, 5-HT1E, and 5-HT1F. There is no 5-HT1C receptor subtype, as it has been reclassified as 5-HT2C receptor. 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. The 5-HT7 receptor is coupled to Gs, which positively stimulates adenylate cyclase activity, leading to increased intracellular cAMP formation 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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDyVWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15064    20 LVIAAILLTRKLHTPANYLIASLAVADLLVAVLVMPLSAVYELTG-RWILGQVLCDIWISLDVTCCTASILHLCVIALDR 98

serotonin receptor subtype 7, member of the class A family of seven-transmembrane G protein-coupled receptors; The 5-HT7 receptor, one of 14 mammalian serotonin receptors, is a member of the class A of GPCRs and is activated by the neurotransmitter serotonin (5-hydroxytryptamine, 5-HT). 5-HT7 receptor mainly couples to Gs protein, which positively stimulates adenylate cyclase, leading to increased intracellular cAMP formation and calcium influx. 5-HT7 receptor is expressed in various human tissues, mainly in the brain, the lower gastrointestinal tract and in vital blood vessels including the coronary artery. 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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15329    20 LVIIAVCLVKKLRTPSNYLIVSLAVSDLLVALLVMPLAIIYELSGY-WPFGEILCDVWISFDVLLCTASILNLCAISVDR 98

serotonin receptor subtype 2 from insects, 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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  54 NWPALSIVIIIIMTIGGNILVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCPVWISL 133
Cdd:cd15307     1 NYWALLALVLVLGTAAGNILVCLAIAWERRLQNVTNYFLMSLAITDLMVAVLVMPLGILTLVKGH-FPLSSEHCLTWICL 79

                          90       100       110
                  ....*....|....*....|....*....|....*...
gi 1934150654 134 DVLFSTASIMHLCAISLDRCIS-SYPCDWteGRRKGVR 170
Cdd:cd15307    80 DVLFCTASIMHLCTISVDRYLSlRYPMRF--GRNKTRR 115

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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15051    20 LVCLAVAVNRRLRNLTNYFIVSLAVTDLLLGLLVLPFSAIYELRGE-WPLGPVFCNIYISLDVMLCTASILNLFAISLDR 98

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        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15065    19 LVCLAIFTDRRLRKKSNLFIVSLAVADLLVALLVMTFAVVNDLLGY-WLFGETFCNIWISFDVMCSTASILNLCAISLDR 97

                  ..
gi 1934150654 153 CI 154
Cdd:cd15065    98 YI 99

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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLH-NATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYlCPVWISLDVLFSTASIMHLCAISLD 151
Cdd:cd15057    20 LVIAAVLRFRHLRsKVTNYFIVSLAVSDLLVAILVMPWAAVNEVAGY-WPFGSF-CDVWVSFDIMCSTASILNLCVISVD 97

                  .
gi 1934150654 152 R 152
Cdd:cd15057    98 R 98

muscarinic acetylcholine receptor subfamily, 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. 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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15049    20 LVILSFRVNRQLRTVNNYFLLSLACADLIIGLVSMNLYTVYLVMGY-WPLGPLLCDLWLALDYVASNASVMNLLLISFDR 98

                          90
                  ....*....|....*...
gi 1934150654 153 CIS-----SYPCDWTEGR 165
Cdd:cd15049    99 YFSvtrplTYRAKRTPKR 116

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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILyDYVWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15314    20 LVIISIAHFKQLHTPTNYLILSLAVADLLVGGLVMPPSMVRSV-ETCWYFGDLFCKIHSSFDITLCTASILNLCFISIDR 98

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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSllAILYDYV-WPLPRYLCPVWISLDVLFSTASIMHLCAISLD 151
Cdd:cd15055    20 LVIISISHFKQLHTPTNLLLLSLAVADFLVGLLVMPFS--MIRSIETcWYFGDTFCKLHSSLDYILTSASIFNLVLIAID 97

                  .
gi 1934150654 152 R 152
Cdd:cd15055    98 R 98

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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15058    20 LVIIAIARTSRLQTMTNIFITSLACADLVMGLLVVPLGATIVVTGK-WQLGNFWCELWTSVDVLCVTASIETLCVIAVDR 98

                  ...
gi 1934150654 153 CIS 155
Cdd:cd15058    99 YIA 101

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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15056    20 LVIVAVCTDRQLRKKTNYFVVSLAVADLLVAVLVMPFGAIELVNNR-WIYGETFCLVRTSLDVLLTTASIMHLCCIALDR 98

alpha-2 adrenergic receptors subtype B, 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        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15321    26 LVIIAVLTSRSLRAPQNLFLVSLAAADILVATLIIPFSLANELMGY-WYFRKTWCEIYLALDVLFCTSSIVHLCAISLDR 104

D4 dopamine receptor of the D2-like family, 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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYVWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15308    20 LVCLSVCTERALKTTTNYFIVSLAVADLLLALLVLPLYVYSEFQGGVWTLSPVLCDALMTMDVMLCTASIFNLCAISVDR 99

                  ...
gi 1934150654 153 CIS 155
Cdd:cd15308   100 FIA 102

serotonin receptor subtypes 1B and 1D, 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        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1934150654  74 VIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILyDYVWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15333    25 VIATIYLTRKLHTPANYLIASLAVTDLLVSILVMPISIVYTV-TGTWTLGQVVCDIWLSSDITCCTASILHLCVIALDR 102

serotonin receptor subtype 1F, 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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDyVWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15334    20 LVITAIIVTRKLHHPANYLICSLAVTDFLVAVLVMPFSIMYIVKE-TWIMGQVVCDIWLSVDITCCTCSILHLSAIALDR 98

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        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15322    20 LVIIAVFTSRALKAPQNLFLVSLASADILVATLVIPFSLANEVMGY-WYFGKVWCEIYLALDVLFCTSSIVHLCAISLDR 98

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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILyDYVWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15317    20 VVIISISHFKQLHSPTNMLVLSLATADFLLGLCVMPFSMIRTV-ETCWYFGDLFCKFHTGLDLLLCTTSIFHLCFIAIDR 98

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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  74 VIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPlslLAILYDYV--WPLPRYLCPVWISLDVLFSTASIMHLCAISLD 151
Cdd:cd15330    21 VVAAIALERSLQNVANYLIGSLAVTDLMVSVLVLP---MAALYQVLnkWTLGQVTCDLFIALDVLCCTSSILHLCAIALD 97

                  .
gi 1934150654 152 R 152
Cdd:cd15330    98 R 98

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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15060    20 LVILSVFTYRPLRIVQNFFIVSLAVADLAVAIFVLPLNVAYFLLGK-WLFGIHLCQMWLTCDILCCTASILNLCAIALDR 98

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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDyVWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd14993    20 LVIAVVLRNKHMRTVTNYFLVNLAVADLLVSLFCMPLTLLENVYR-PWVFGEVLCKAVPYLQGVSVSASVLTLVAISIDR 98

                  ....*..
gi 1934150654 153 CIS-SYP 158
Cdd:cd14993    99 YLAiCYP 105

muscarinic acetylcholine receptor subtype M2, 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. Activation of M2 receptor causes a decrease in cAMP production, generally leading to inhibitory-type effects. This causes an outward current of potassium in the heart, resulting in a decreased heart rate. 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        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15297    20 LVMVSIKVNRHLQTVNNYFLFSLACADLIIGVFSMNLYTLYTVIGY-WPLGPVVCDLWLALDYVVSNASVMNLLIISFDR 98

                          90
                  ....*....|.
gi 1934150654 153 --CIS---SYP 158
Cdd:cd15297    99 yfCVTkplTYP 109

beta-2 adrenergic receptors (adrenoceptors), member of the class A family of seven-transmembrane G protein-coupled receptors; Beta-2 AR is activated by adrenaline that plays important roles in cardiac function and pulmonary physiology. While beta-1 AR and beta-2 AR 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, beta-2 AR can couple to both G(s) and G(i) proteins in the heart. Moreover, beta-2 AR activation leads to smooth muscle relaxation and bronchodilation in the lung. The beta adrenergic receptors are a subfamily of the class A rhodopsin-like G protein-coupled receptors.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDyVWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15957    20 LVITAIAKFERLQTVTNYFITSLACADLVMGLAVVPFGAAHILLK-TWTFGNFWCEFWTSIDVLCVTASIETLCVIAVDR 98

neuropeptide Y receptors and related proteins, member of the class A family of seven-transmembrane G protein-coupled receptors; NPY is a 36-amino acid peptide neurotransmitter with a C-terminal tyrosine amide residue that is widely distributed in the brain and the autonomic nervous system of many mammalian species. NPY exerts its functions through five, G-protein coupled receptor subtypes including NPY1R, NPY2R, NPY4R, NPY5R, and NPY6R; however, NPY6R is not functional in humans. NYP receptors are also activated by its two other family members, peptide YY (PYY) and pancreatic polypeptide (PP). They typically couple to Gi or Go proteins, which leads to a decrease in adenylate cyclase activity, thereby decreasing intracellular cAMP levels, and are involved in diverse physiological roles including appetite regulation, circadian rhythm, and anxiety. Also included in this subgroup is prolactin-releasing peptide (PrRP) receptor (previously known as GPR10), which is activated by its endogenous ligand PrRP, a neuropeptide possessing C-terminal Arg-Phe-amide motif. There are two active isoforms of PrRP in mammals: one consists of 20 amino acid residues (PrRP-20) and the other consists of 31 amino acid residues (PrRP-31). PrRP receptor shows significant sequence homology to the NPY receptors, and a micromolar level of NPY can bind and completely inhibit the PrRP-evoked intracellular calcium response in PrRP receptor-expressing cells, suggesting that the PrRP receptor shares a common ancestor with the NPY receptors.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLC---PVWISLDVLFSTASIMhlcAIS 149
Cdd:cd15203    20 LVIYVVLRNKSMQTVTNIFILNLAVSDLLLCLVSLPFTLIYTLTKN-WPFGSILCklvPSLQGVSIFVSTLTLT---AIA 95

                  ....*
gi 1934150654 150 LDRCI 154
Cdd:cd15203    96 IDRYQ 100

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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDyVWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15958    20 LVIVAIGRTQRLQTLTNLFITSLACADLVMGLLVVPFGATLVVRG-RWLYGSFFCELWTSVDVLCVTASIETLCVIAIDR 98

                          90       100
                  ....*....|....*....|..
gi 1934150654 153 CIS-----SYPCDWTEGRRKGV 169
Cdd:cd15958    99 YLAitspfRYQSLLTRARAKGI 120

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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILyDYVWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15318    20 FVVVTVSHFKALHTPTNFLLLSLALADMLLGLTVLPFSTIRSV-ESCWYFGDSFCRLHTCLDTLFCLTSIFHLCFISIDR 98

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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSL-LAILYDyvWPLPRYLCPVWISLDVLFSTASIMHLCAISLD 151
Cdd:cd15309    20 LVCMAVSREKALQTTTNYLIVSLAVADLLVATLVMPWVVyLEVVGE--WRFSRIHCDIFVTLDVMMCTASILNLCAISID 97

                  .
gi 1934150654 152 R 152
Cdd:cd15309    98 R 98

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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCPVWISLDVLFSTASIMHLCAISLDR 152
Cdd:cd15299    23 LVIVSFKVNKQLKTVNNYFLLSLACADLIIGVISMNLFTTYIIMNR-WALGNLACDLWLSIDYVASNASVMNLLVISFDR 101

                  ...
gi 1934150654 153 CIS 155
Cdd:cd15299   102 YFS 104

muscarinic acetylcholine receptor GAR-2 and similar proteins, 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. 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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  72 ILVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYVWPLPRYLCPVWISLDVLFSTASIMHLCAISLD 151
Cdd:cd15302    19 ILVLLSFYVDRNIRQPSNYFIASLAVSDLLIGLESMPFYTVYVLNGDYWPLGWVLCDLWLSVDYTVCLVSIYTVLLITID 98

                  ....
gi 1934150654 152 RCIS 155
Cdd:cd15302    99 RYCS 102

type 2 opsins in animals, member of the class A family of seven-transmembrane G protein-coupled receptors; This rhodopsin family represents the type 2 opsins found in vertebrates and invertebrates except sponge. Type 2 opsins primarily function as G protein coupled receptors and are responsible for vision as well as for circadian rhythm and pigment regulation. On the contrary, type 1 opsins such as bacteriorhodopsin and proteorhodopsin are found in both prokaryotic and eukaryotic microbes, functioning as light-gated ion channels, proton pumps, sensory receptors and in other unknown functions. Although these two opsin types share seven-transmembrane domain topology and a conserved lysine reside in the seventh helix, type 1 opsins do not activate G-proteins and are not evolutionarily related to type 2. Type 2 opsins can be classified into six distinct subfamilies including the vertebrate opsins/encephalopsins, the G(o) opsins, the G(s) opsins, the invertebrate G(q) opsins, the photoisomerases, and the neuropsins.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1934150654  73 LVIMAVSMEKKLHNATNYFLMSLAIADMLVGLLVMPLSLLAILYDYvWPLPRYLCpVWISLDV-LFSTASIMHLCAISLD 151
Cdd:cd14969    20 LVIIVFLKKKKLRTPLNLFLLNLALADLLMSVVGYPLSFYSNLSGR-WSFGDPGC-VIYGFAVtFLGLVSISTLAALAFE 97

                  ....
gi 1934150654 152 RCIS 155
Cdd:cd14969    98 RYLV 101