seven-transmembrane G protein-coupled receptor superfamily; This hierarchical evolutionary model represents the seven-transmembrane (7TM) receptors, often referred to as G protein-coupled receptors (GPCRs), which transmit physiological signals from the outside of the cell to the inside via G proteins. GPCRs constitute the largest known superfamily of transmembrane receptors across the three kingdoms of life that respond to a wide variety of extracellular stimuli including peptides, lipids, neurotransmitters, amino acids, hormones, and sensory stimuli such as light, smell and taste. All GPCRs share a common structural architecture comprising of seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops. A general feature of GPCR signaling is agonist-induced conformational changes in the receptors, leading to activation of the heterotrimeric G proteins, which consist of the guanine nucleotide-binding G-alpha subunit and the dimeric G-beta-gamma subunits. The activated G proteins then bind to and activate numerous downstream effector proteins, which generate second messengers that mediate a broad range of cellular and physiological processes. However, some 7TM receptors, such as the type 1 microbial rhodopsins, do not activate G proteins. Based on sequence similarity, GPCRs can be divided into six major classes: class A (the rhodopsin-like family), class B (the Methuselah-like, adhesion and secretin-like receptor family), class C (the metabotropic glutamate receptor family), class D (the fungal mating pheromone receptors), class E (the cAMP receptor family), and class F (the frizzled/smoothened receptor family). Nearly 800 human GPCR genes have been identified and are involved essentially in all major physiological processes. Approximately 40% of clinically marketed drugs mediate their effects through modulation of GPCR function for the treatment of a variety of human diseases including bacterial infections.

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gi 746891777   1 FIIVMLLASLNSCCNPWIYMLFTGHLFHEL 30
Cdd:cd15387  268 FIIAMLLASLNSCCNPWIYMFFTGHLFHDL 297

oxytocin receptor, member of the class A family of seven-transmembrane G protein-coupled receptors; Oxytocin is a peptide of nine amino acids synthesized in the hypothalamus and is released from the posterior pituitary gland. Oxytocin plays an important role in sexual reproduction of both sexes and is structurally very similar to vasopressin. Although vasopressin and oxytocin differ only by two amino acids and stimulate the same cAMP/PKA pathway, they have divergent physiological functions. Vasopressin is involved in regulating blood pressure and the balance of water and sodium ions, whereas oxytocin plays an important role in the uterus during childbirth and in lactation.

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gi 746891777   1 FIIVMLLASLNSCCNPWIYMLFTGHLFHEL 30
Cdd:cd15387  268 FIIAMLLASLNSCCNPWIYMFFTGHLFHDL 297

oxytocin receptor, member of the class A family of seven-transmembrane G protein-coupled receptors; Oxytocin is a peptide of nine amino acids synthesized in the hypothalamus and is released from the posterior pituitary gland. Oxytocin plays an important role in sexual reproduction of both sexes and is structurally very similar to vasopressin. Although vasopressin and oxytocin differ only by two amino acids and stimulate the same cAMP/PKA pathway, they have divergent physiological functions. Vasopressin is involved in regulating blood pressure and the balance of water and sodium ions, whereas oxytocin plays an important role in the uterus during childbirth and in lactation.

                         10        20        30
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gi 746891777   1 FIIVMLLASLNSCCNPWIYMLFTGHLFHEL 30
Cdd:cd15387  268 FIIAMLLASLNSCCNPWIYMFFTGHLFHDL 297

vasopressin receptor subtype 1B, member of the class A family of seven-transmembrane G protein-coupled receptors; The V1b receptor is specifically expressed in corticotropes of the anterior pituitary and plays a critical role in regulating the activity of hypothalamic-pituitary-adrenal axis, a key part of the neuroendocrine system that controls reactions to stress, by maintaining adrenocorticotropic hormone (ACTH) and corticosterone levels. Vasopressin (also known as arginine vasopressin or anti-diuretic hormone) is synthesized in the hypothalamus and is released from the posterior pituitary gland. The actions of vasopressin are mediated by the interaction of this hormone with three receptor subtypes: V1aR, V1bR, and V2R. These subtypes are differ in localization, function, and signaling pathways. Activation of V1aR and V1bR stimulate phospholipase C, while activation of V2R stimulates adenylate cyclase. Although vasopressin and oxytocin differ only by two amino acids and stimulate the same cAMP/PKA pathway, they have divergent physiological functions. Vasopressin is involved in regulating blood pressure and the balance of water and sodium ions, whereas oxytocin plays an important role in the uterus during childbirth and in lactation.

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gi 746891777   1 FIIVMLLASLNSCCNPWIYMLFTGHLFHE 29
Cdd:cd15386  273 FTITMLLASLSSCCNPWIYMFFSGHLLQD 301

vasopressin receptor 2, member of the class A family of seven-transmembrane G protein-coupled receptors; The vasopressin type 2 receptor (V2R) is a G(s)-coupled receptor that controls balance of water and sodium ion by regulating their reabsorption in the renal collecting duct. Mutations of V2R is responsible for nephrogenic diabetes insipidus. Vasopressin (also known as arginine vasopressin or anti-diuretic hormone) is synthesized in the hypothalamus and is released from the posterior pituitary gland. The actions of vasopressin are mediated by the interaction of this hormone with three receptor subtypes: V1aR, V1bR, and V2R. These subtypes are differ in localization, function, and signaling pathways. Activation of V1aR and V1bR stimulate phospholipase C, while activation of V2R stimulates adenylate cyclase. Although vasopressin and oxytocin differ only by two amino acids and stimulate the same cAMP/PKA pathway, they have divergent physiological functions. Vasopressin is involved in regulating blood pressure and the balance of water and sodium ions, whereas oxytocin plays an important role in the uterus during childbirth and in lactation.

                         10        20        30
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gi 746891777   1 FIIVMLLASLNSCCNPWIYMLFTGHLFHEL 30
Cdd:cd15388  266 FTILMLLASLNSCTNPWIYMAFSSSVSKEL 295