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 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLFN-WNFGSGICMFWLITD 94
Cdd:cd15295     1 VVLLFLMSLLALVIVLGNALVIIAFVVDKNLRHRSNYFFLNLAISDFFVGAISIPLYIPYTLTNrWDFGRGLCVFWLVID 80

                          90       100       110
                  ....*....|....*....|....*....|....*
gi 1039755817  95 YLLCTASVYNIVLISYDRYQSVSNACVHSVMHSHT 129
Cdd:cd15295    81 YLLCTASVYNIVLISYDRYQSVSNAVSYRNQQTAT 115

histamine receptor subtype H4R, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes histamine subtype H4R, a member 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        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLFN-WNFGSGICMFWLITD 94
Cdd:cd15295     1 VVLLFLMSLLALVIVLGNALVIIAFVVDKNLRHRSNYFFLNLAISDFFVGAISIPLYIPYTLTNrWDFGRGLCVFWLVID 80

                          90       100       110
                  ....*....|....*....|....*....|....*
gi 1039755817  95 YLLCTASVYNIVLISYDRYQSVSNACVHSVMHSHT 129
Cdd:cd15295    81 YLLCTASVYNIVLISYDRYQSVSNAVSYRNQQTAT 115

chemokine receptor-like protein; Provisional

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  30 MVGNAVVILAFVVDRNLRHRSNYFFlNLAISDFLVgLISIPLYIPHVLFNWNFGSGICMFWLITDYLLCTASVYNIVLIS 109
Cdd:PHA02834   43 LIGNVLVIAVLIVKRFMFVVDVYLF-NIAMSDLML-VFSFPFIIHNDLNEWIFGEFMCKLVLGVYFVGFFSNMFFVTLIS 120

                          90
                  ....*....|
gi 1039755817 110 YDRYQSVSNA 119
Cdd:PHA02834  121 IDRYILVVNA 130

histamine receptor subtype H4R, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes histamine subtype H4R, a member 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        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLFN-WNFGSGICMFWLITD 94
Cdd:cd15295     1 VVLLFLMSLLALVIVLGNALVIIAFVVDKNLRHRSNYFFLNLAISDFFVGAISIPLYIPYTLTNrWDFGRGLCVFWLVID 80

                          90       100       110
                  ....*....|....*....|....*....|....*
gi 1039755817  95 YLLCTASVYNIVLISYDRYQSVSNACVHSVMHSHT 129
Cdd:cd15295    81 YLLCTASVYNIVLISYDRYQSVSNAVSYRNQQTAT 115

histamine receptor subtypes H3R and H3R-like, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes histamine subtypes H3R and H3R-like, 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        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLF-NWNFGSGICMFWLITD 94
Cdd:cd15296     1 VILAVLMALLVVATVLGNALVILAFVVDSSLRTQGNFFFLNLAISDFLVGGFCIPLYIPYVLTgRWKFGRGLCKLWLVVD 80

                          90       100       110
                  ....*....|....*....|....*....|....*
gi 1039755817  95 YLLCTASVYNIVLISYDRYQSVSNACVHSVMHSHT 129
Cdd:cd15296    81 YLLCTASVFNIVLISYDRFLSVTRAVSYRAQKGMT 115

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 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLFN--WNFGSGICMFWLIT 93
Cdd:cd15302     1 ILLALITAILSIITVIGNILVLLSFYVDRNIRQPSNYFIASLAVSDLLIGLESMPFYTVYVLNGdyWPLGWVLCDLWLSV 80

                          90       100
                  ....*....|....*....|...
gi 1039755817  94 DYLLCTASVYNIVLISYDRYQSV 116
Cdd:cd15302    81 DYTVCLVSIYTVLLITIDRYCSV 103

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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPH-VLFNWNFGSGICMFWLITD 94
Cdd:cd15059     1 VAISSIVSVVILLIIVGNVLVIVAVLTSRKLRAPQNWFLVSLAVADILVGLLIMPFSLVNeLMGYWYFGSVWCEIWLALD 80

                          90       100
                  ....*....|....*....|....*
gi 1039755817  95 YLLCTASVYNIVLISYDRYQSVSNA 119
Cdd:cd15059    81 VLFCTASIVNLCAISLDRYWSVTQA 105

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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLFN-WNFGSGICMFWLITD 94
Cdd:cd15301     1 VLIVIVAAVLSLVTVGGNVMVMISFKIDKQLQTISNYFLFSLAVADFAIGVISMPLFTVYTALGyWPLGYEVCDTWLAID 80

                          90       100
                  ....*....|....*....|...
gi 1039755817  95 YLLCTASVYNIVLISYDRYQSVS 117
Cdd:cd15301    81 YLASNASVLNLLIISFDRYFSVT 103

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 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLFN-WNFGSGICMFWLITD 94
Cdd:cd15299     4 VLIAFLTGILALVTIIGNILVIVSFKVNKQLKTVNNYFLLSLACADLIIGVISMNLFTTYIIMNrWALGNLACDLWLSID 83

                          90       100
                  ....*....|....*....|...
gi 1039755817  95 YLLCTASVYNIVLISYDRYQSVS 117
Cdd:cd15299    84 YVASNASVMNLLVISFDRYFSIT 106

histamine subtype H1 receptor, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes histamine receptor subtype H1R, 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). H1R selectively interacts with the G(q)-type G protein that activates phospholipase C and the phosphatidylinositol pathway. Antihistamines, a widely used anti-allergy medication, act on the H1 subtype and produce drowsiness as a side effect. 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 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLFN-WNFGSGICMFWLITD 94
Cdd:cd15050     1 APLGIALSTISLITVILNLLVLYAVRTERKLHTVGNLYIVSLSVADLIVGAVVMPLNIVYLLESkWILGRPVCLFWLSMD 80

                          90       100
                  ....*....|....*....|...
gi 1039755817  95 YLLCTASVYNIVLISYDRYQSVS 117
Cdd:cd15050    81 YVASTASIFSLFILCIDRYRSVQ 103

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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  18 LAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPL-YIPHVLFNWNFGSGICMFWLITDYL 96
Cdd:cd15331     3 TSIILGLLILATIIGNVFVIAAILLERSLQGVSNYLILSLAVADLMVAVLVMPLsAVYEVSQHWFLGPEVCDMWISMDVL 82

                          90       100
                  ....*....|....*....|....
gi 1039755817  97 LCTASVYNIVLISYDRYQSVSNAC 120
Cdd:cd15331    83 CCTASILHLVAIALDRYWAVTNID 106

tyramine receptors and similar proteins, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes tyramine-specific receptors and similar proteins found in insects and other invertebrates. These tyramine receptors form a distinct receptor family that is phylogenetically different from the other tyramine/octopamine receptors which also found in 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 1039755817  18 LAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYI-PHVLFNWNFGSGICMFWLITDYL 96
Cdd:cd15061     2 LISFLILAIIFTIFGNLLVILAVATTRRLRTITNCYIVSLATADLLVGVLVLPLAIiRQLLGYWPLGSHLCDFWISLDVL 81

                          90       100
                  ....*....|....*....|..
gi 1039755817  97 LCTASVYNIVLISYDRYQSVSN 118
Cdd:cd15061    82 LCTASILNLCCISLDRYFAITY 103

muscarinic acetylcholine receptor subtype M1, 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. M1 is the dominant mAChR subtype involved in learning and memory. It is linked to synaptic plasticity, neuronal excitability, and neuronal differentiation during early development. 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 1039755817  25 FAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLF-NWNFGSGICMFWLITDYLLCTASVY 103
Cdd:cd17790    10 LSLVTVTGNLLVLISFKVNSELKTVNNYFLLSLACADLIIGAFSMNLYTTYILMgHWALGTVACDLWLALDYVASNASVM 89

                          90
                  ....*....|....
gi 1039755817 104 NIVLISYDRYQSVS 117
Cdd:cd17790    90 NLLIISFDRYFSIT 103

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 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPH-VLFNWNFGSGICMFWLITD 94
Cdd:cd15297     1 VFIVLVAGSLSLVTIIGNILVMVSIKVNRHLQTVNNYFLFSLACADLIIGVFSMNLYTLYtVIGYWPLGPVVCDLWLALD 80

                          90       100       110
                  ....*....|....*....|....*....|....
gi 1039755817  95 YLLCTASVYNIVLISYDRYQSVSNACVHSVMHSH 128
Cdd:cd15297    81 YVVSNASVMNLLIISFDRYFCVTKPLTYPVKRTT 114

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 1039755817  17 PLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLFN-WNFGSGICMFWLITDY 95
Cdd:cd15065     1 LIGIFLSLIIVLAIFGNVLVCLAIFTDRRLRKKSNLFIVSLAVADLLVALLVMTFAVVNDLLGyWLFGETFCNIWISFDV 80

                          90       100
                  ....*....|....*....|..
gi 1039755817  96 LLCTASVYNIVLISYDRYQSVS 117
Cdd:cd15065    81 MCSTASILNLCAISLDRYIHIK 102

alpha-1 adrenergic receptors subtype B, 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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIP-HVLFNWNFGSGICMFWLITD 94
Cdd:cd15326     1 ILLGLVLGAFILFAIVGNILVILSVVCNRHLRIPTNYFIVNLAIADLLLSFTVLPFSATlEILGYWVFGRIFCDIWAAVD 80

                          90       100
                  ....*....|....*....|...
gi 1039755817  95 YLLCTASVYNIVLISYDRYQSVS 117
Cdd:cd15326    81 VLCCTASILSLCAISIDRYIGVR 103

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        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  29 IMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIP-HVLFNWNFGSGICMFWLITDYLLCTASVYNIVL 107
Cdd:cd15063    14 VVLGNLLVIAAVLCSRKLRTVTNLFIVSLACADLLVGTLVLPFSAVnEVLDVWIFGHTWCQIWLAVDVWMCTASILNLCA 93

                          90
                  ....*....|
gi 1039755817 108 ISYDRYQSVS 117
Cdd:cd15063    94 ISLDRYLAIT 103

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 1039755817  32 GNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLFN--WNFGSGICMFWLITDYLLCTASVYNIVLIS 109
Cdd:cd15305    17 GNILVIMAVSLEKKLQNATNFFLMSLAVADMLVGILVMPVSLIAILYDyaWPLPRYLCPIWISLDVLFSTASIMHLCAIS 96

                          90       100
                  ....*....|....*....|
gi 1039755817 110 YDRYQSVSNACVHSVMHSHT 129
Cdd:cd15305    97 LDRYVAIRNPIEHSRFNSRT 116

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        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  18 LAFLMSsfafaiMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPL-YIPHVLFNWNFGSGICMFWLITDYL 96
Cdd:cd15207     9 LIFLLC------VVGNVLVCLVVAKNPRMRTVTNYFILNLAVSDLLVGVFCMPFtLVDNILTGWPFGDVMCKLSPLVQGV 82

                          90       100
                  ....*....|....*....|
gi 1039755817  97 LCTASVYNIVLISYDRYQSV 116
Cdd:cd15207    83 SVAASVFTLVAIAVDRYRAV 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        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  13 AAQVPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPH-VLFNWNFGSGICMFWL 91
Cdd:cd15333     2 GLKISLAVLLALITLATTLSNAFVIATIYLTRKLHTPANYLIASLAVTDLLVSILVMPISIVYtVTGTWTLGQVVCDIWL 81

                          90       100       110
                  ....*....|....*....|....*....|..
gi 1039755817  92 ITDYLLCTASVYNIVLISYDRYQSVSNACVHS 123
Cdd:cd15333    82 SSDITCCTASILHLCVIALDRYWAITDAVEYS 113

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 1039755817  30 MVGNAVVILAFVVDRNLRHR-SNYFFLNLAISDFLVGLISIPL-YIPHVLFNWNFGSgICMFWLITDYLLCTASVYNIVL 107
Cdd:cd15057    15 LLGNALVIAAVLRFRHLRSKvTNYFIVSLAVSDLLVAILVMPWaAVNEVAGYWPFGS-FCDVWVSFDIMCSTASILNLCV 93

                          90
                  ....*....|.
gi 1039755817 108 ISYDRYQSVSN 118
Cdd:cd15057    94 ISVDRYWAISS 104

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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIP-HVLFNWNFGSGICMFWLITD 94
Cdd:cd15327     1 VGVGVFLAIFILMAIVGNILVILSVACNRHLQTVTNYFIVNLAIADLLLSTTVLPFSATlEVLGFWAFGRVFCDIWAAVD 80

                          90       100
                  ....*....|....*....|..
gi 1039755817  95 YLLCTASVYNIVLISYDRYQSV 116
Cdd:cd15327    81 VLCCTASILSLCVISVDRYVGV 102

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        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  18 LAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLF-NWNFGSGICMFWLITDYL 96
Cdd:cd15054     3 VAAFLCLIILLTVAGNSLLILLIFTQRSLRNTSNYFLVSLFMSDLMVGLVVMPPAMLNALYgRWVLARDFCPIWYAFDVM 82

                          90
                  ....*....|....*..
gi 1039755817  97 LCTASVYNIVLISYDRY 113
Cdd:cd15054    83 CCSASILNLCVISLDRY 99

alpha-1 adrenergic receptors, 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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLY-IPHVLFNWNFGSGICMFWLITD 94
Cdd:cd15062     1 IVVGVALGAFILFAIGGNLLVILSVACNRHLRTPTHYFIVNLAVADLLLSFTVLPFSaTLEVLGYWAFGRIFCDVWAAVD 80

                          90       100
                  ....*....|....*....|...
gi 1039755817  95 YLLCTASVYNIVLISYDRYQSVS 117
Cdd:cd15062    81 VLCCTASIMSLCVISVDRYIGVR 103

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 1039755817  18 LAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLF-NWNFGSGICMFWLITDYL 96
Cdd:cd15334     3 ISLTLSILALMTTAINSLVITAIIVTRKLHHPANYLICSLAVTDFLVAVLVMPFSIMYIVKeTWIMGQVVCDIWLSVDIT 82

                          90       100
                  ....*....|....*....|....*..
gi 1039755817  97 LCTASVYNIVLISYDRYQSVSNACVHS 123
Cdd:cd15334    83 CCTCSILHLSAIALDRYRAITDAVEYA 109

alpha-2 adrenergic receptors subtype C, 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 1039755817  18 LAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLFN-WNFGSGICMFWLITDYL 96
Cdd:cd15323     3 LAAVVGFLIVFTIVGNVLVVIAVLTSRALRAPQNLFLVSLASADILVATLVMPFSLANELMGyWYFGQVWCNIYLALDVL 82

                          90       100
                  ....*....|....*....|...
gi 1039755817  97 LCTASVYNIVLISYDRYQSVSNA 119
Cdd:cd15323    83 FCTSSIVHLCAISLDRYWSVTQA 105

alpha-2 adrenergic receptors subtype D, 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 1039755817  18 LAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPH-VLFNWNFGSGICMFWLITDYL 96
Cdd:cd15324     3 IVLVVVVIILVTIVGNVLVVVAVFTSRALRAPQNLFLVSLASADILVATLVIPFSLANeVMGYWYFGSTWCAFYLALDVL 82

                          90       100
                  ....*....|....*....|...
gi 1039755817  97 LCTASVYNIVLISYDRYQSVSNA 119
Cdd:cd15324    83 FCTSSIVHLCAISLDRYWSVTKA 105

insect photoreceptors R1-R6 and similar proteins, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes the insect photoreceptors and their closely related proteins. The Drosophila eye is composed of about 800 unit eyes called ommatidia, each of which contains eight photoreceptor cells (R1-R8). The six outer photoreceptors (R1-R6) function like the vertebrate rods and are responsible for motion detection in dim light and image formation. The R1-R6 photoreceptors express a blue-absorbing pigment, Rhodopsin 1(Rh1). The inner photoreceptors (R7 and R8) are considered the equivalent of the color-sensitive vertebrate cone cells, which express a range of different pigments. The R7 photoreceptors express one of two different UV absorbing pigments, either Rh3 or Rh4. Likewise, the R8 photoreceptors express either the blue absorbing pigment Rh5 or green absorbing pigment Rh6. These photoreceptors belong the class A of the G protein-coupled receptors and possess seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  18 LAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVgLISIPLYIPHVLFN-WNFGSGICMFWLITDYL 96
Cdd:cd15079     3 LGFIYIFLGIVSLLGNGLVIYIFSTTKSLRTPSNMLVVNLAISDFLM-MIKMPIFIYNSFYEgWALGPLGCQIYAFLGSL 81

                          90       100
                  ....*....|....*....|..
gi 1039755817  97 LCTASVYNIVLISYDRYQSVSN 118
Cdd:cd15079    82 SGIGSIWTNAAIAYDRYNVIVK 103

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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  16 VPLAFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLY-IPHVLFNWNFGSGICMFWLITD 94
Cdd:cd15325     1 IVLGVILGGFILFGVLGNILVILSVACHRHLQTVTHYFIVNLAVADLLLTSTVLPFSaIFEILGYWAFGRVFCNIWAAVD 80

                          90       100
                  ....*....|....*....|...
gi 1039755817  95 YLLCTASVYNIVLISYDRYQSVS 117
Cdd:cd15325    81 VLCCTASIMSLCIISIDRYIGVS 103

Drosophila melanogaster beta-adrenergic receptor-like octopamine receptors and similar receptors in bilateria; member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes Drosophila beta-adrenergic-like octopamine receptors and similar proteins. The biogenic amine octopamine is the invertebrate equivalent of vertebrate adrenergic neurotransmitters and exerts its effects through different G protein-coupled receptor types. Insect octopamine receptors are involved in the modulation of carbohydrate metabolism, muscular tension, cognition and memory. The activation of octopamine receptors mediating these actions leads to an increase in adenylate cyclase activity, thereby increasing cAMP levels. In Drosophila melanogaster, three subgroups have been classified on the basis of their structural homology and functional equivalents with vertebrate beta-adrenergic receptors: DmOctBeta1R, DmOctBeta2R, and DmOctBeta3R.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1039755817  19 AFLMSSFAFAIMVGNAVVILAFVVDRNLRHRSNYFFLNLAISDFLVGLISIPLYIPHVLFN-WNFGSGICMFWLITDYLL 97
Cdd:cd15066     3 GFAMTLIILAAIFGNLLVIISVMRHRKLRVITNYFVVSLAMADMLVALCAMTFNASVEITGrWMFGYFMCDVWNSLDVYF 82

                          90       100
                  ....*....|....*....|.
gi 1039755817  98 CTASVYNIVLISYDRYQSVSN 118
Cdd:cd15066    83 STASILHLCCISVDRYYAIVQ 103