The angiotensin receptors are a class of G protein-coupled receptors with angiotensins as ligands.[1] They are important in the renin-angiotensin system: they are responsible for the signal transduction of the main effector hormone.[2] [edit] Structure The AT1 and AT2 receptors share a sequence identity of ~30%, but have a similar affinity for angiotensin II, which is their main ligand. [edit] Members [edit] Overview table | Receptor | Mechanism[3] | | AT1 | | | AT2 | | | AT3 | | | AT4 | | The AT1 receptor is the best elucidated angiotensin receptor. [edit] Mechanism The angiotensin receptor is activated by the vasoconstricting peptide angiotensin II. The activated receptor in turn couples to Gq/11 and Gi/o and thus activates phospholipase C and increases the cytosolic Ca2+ concentrations, which in turn triggers cellular responses such as stimulation of protein kinase C. Activated receptor also inhibits adenylate cyclase and activates various tyrosine kinases.[2] [edit] Effects Effects mediated by the AT1 receptor include vasoconstriction, aldosterone synthesis and secretion, increased vasopressin secretion, cardiac hypertrophy, augmentation of peripheral noradrenergic activity, vascular smooth muscle cells proliferation, decreased renal blood flow, renal renin inhibition, renal tubular sodium reuptake, modulation of central sympathetic nervous system activity, cardiac contractility, central osmocontrol and extracellular matrix formation.[4] AT2 receptors are more plentiful in the fetus and neonate. The AT2 receptor remains enigmatic and controversial. Effects mediated by the AT2 receptor are suggested to include inhibition of cell growth, fetal tissue development, modulation of extracellular matrix, neuronal regeneration, apoptosis, cellular differentiation, and maybe vasodilation and left ventricular hypertrophy[5]. [edit] AT3 and AT4 Other poorly characterized subtypes include the AT3 and AT4 receptors. The AT4 receptor is activated by the angiotensin II metabolite angiotensin IV, and may play a role in regulation of the CNS extracellular matrix. [edit] See also [edit] References - ^ de Gasparo M, Catt KJ, Inagami T, Wright JW, Unger T (2000). "International union of pharmacology. XXIII. The angiotensin II receptors". Pharmacol. Rev. 52 (3): 415–72. PMID 10977869. http://pharmrev.aspetjournals.org/cgi/content/abstract/52/3/415.
- ^ a b Higuchi S, Ohtsu H, Suzuki H, Shirai H, Frank GD, Eguchi S (2007). "Angiotensin II signal transduction through the AT1 receptor: novel insights into mechanisms and pathophysiology". Clin. Sci. 112 (8): 417–28. doi:10.1042/CS20060342. PMID 17346243.
- ^ Unless else specified in box, then ref is: Senselab
- ^ Catt KJ, Mendelsohn FA, Millan MA, Aguilera G (1984). "The role of angiotensin II receptors in vascular regulation". J. Cardiovasc. Pharmacol. 6 Suppl 4: S575–86. doi:10.1097/00005344-198406004-00004. PMID 6083400.
- ^ *D'Amore A, Black MJ, Thomas WG (2005). "The angiotensin II type 2 receptor causes constituative growth of cardiomyocytes and does not antagonize angiotensin II type 1 receptor-mediated hypertrophy". Hypertension 46: 1347–1354. PMID 16286564.
[edit] External links | Transmembrane receptor: G protein-coupled receptors | | | Class A: Rhodopsin like | | | | | | | | | | | | | | | GPR ( 1, 3, 4, 6, 12, 15, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 31, 32, 33, 34, 35, 37, 39, 42, 44, 45, 50, 52, 55, 61, 62, 63, 65, 68, 75, 77, 78, 82, 83, 84, 85, 87, 88, 92, 101, 103, 109A, 109B, 119, 120, 132, 135, 137B, 139, 141, 142, 146, 148, 149, 150, 151, 152, 153, 160, 161, 162, 171, 173, 174, 176, 177, 182) | | | | Adenosine ( A1, A2A, A2B, A3) · P2Y ( 1, 2, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14) | | | | | | | Other | Acetylcholine ( M1, M2, M3, M4, M5) · Adrenomedullin · Anaphylatoxin ( C3a, C5a) · Angiotensin ( 1, 2) · Apelin · Bile acid · Bombesin ( BRS3, GRPR, NMBR) · Bradykinin ( B1, B2) · Cannabinoid ( CB1, CB2) · Chemokine · Cholecystokinin ( A, B) · Dopamine ( D1, D2, D3, D4, D5) · EBI2 · Endothelin ( A, B) · Estrogen · Formyl peptide ( 1, 2, 3) · Free fatty acid ( 1, 2, 3, 4) · FSH · Galanin ( 1, 2, 3) · Gonadotropin-releasing hormone ( 1, 2) · GHB receptor · Ghrelin · Histamine ( H1, H2, H3, H4) · Kisspeptin · Luteinizing hormone/choriogonadotropin · lysophosphatidic acid ( 1, 2, 3) · Lysophospholipid ( 1, 2, 3, 4, 5, 6, 7, 8) · MAS ( 1, 1L, D, E, F, G, X1, X2, X3, X4) · Melanocortin ( 1, 2, 3, 4, 5) · MCHR ( 1, 2) · Melatonin ( 1A, 1B, 1C) · Niacin ( 1, 2) · Motilin · Opioid ( Delta, Kappa, Mu, Nociceptin & Zeta, but not Sigma) · Olfactory · Opsin ( 3, 4, 5, 1LW, 1MW, 1SW, RGR, RRH) · Orexin ( 1, 2) · Oxytocin · Oxoglutarate · PAF · Prokineticin ( 1, 2) · Prolactin-releasing peptide · Protease-activated ( 1, 2, 3, 4) · Relaxin ( 1, 2, 3, 4) · Somatostatin ( 1, 2, 3, 4, 5) · Sphingosine-1-phosphate ( 1, 2, 3, 4, 5) · SREB · Succinate · TAAR ( 1, 2, 3, 5, 6, 8, 9) · Tachykinin ( 1, 2, 3) · Thyrotropin · Thyrotropin-releasing hormone · Urotensin-II · Vasopressin ( 1A, 1B, 2) | | | | Class B: Secretin like | | | GPR ( 56, 64, 97, 98, 110, 111, 112, 113, 114, 115, 116, 123, 124, 125, 126, 128, 133, 143, 144, 157) | | | Other | Brain-specific angiogenesis inhibitor ( 1, 2, 3) · Cadherin ( 1, 2, 3) · Calcitonin · CALCRL · CD97 · Corticotropin-releasing hormone ( 1, 2) · EMR ( 1, 2, 3) · Glucagon ( GR, GIPR, GLP1R, GLP2R) · Growth hormone releasing hormone · PACAPR1 · GPR · Latrophilin ( 1, 2, 3, ELTD1) · Methuselah-like proteins · Parathyroid hormone ( 1, 2) · Secretin · Vasoactive intestinal peptide ( 1, 2) | | | Class C: Metabotropic
glutamate / pheromone | | | TAS1R ( 1, 2, 3) · TAS2R ( 1, 3, 4, 5, 8, 9, 10, 12, 13, 14, 16, 38, 39, 40, 41, 43, 44, 45, 46, 47, 48, 49, 50) | | | Other | Calcium-sensing receptor · GABA B ( 1, 2) · Glutamate receptor ( Metabotropic glutamate ( 1, 2, 3, 4, 5, 6, 7, 8)) · GPRC6A · GPR ( 156, 158, 179) · RAIG ( 1, 2, 3, 4) | | | | Frizzled / Smoothened | | | |
