| Primary Identifier | IPR000161 | Type | Family |
| Short Name | Vprsn_rcpt_V2 |
| description | G protein-coupled receptors (GPCRs) constitute a vast protein family that encompasses a wide range of functions, including various autocrine, paracrine and endocrine processes. They show considerable diversity at the sequence level, on the basis of which they can be separated into distinct groups []. The term clan can be used to describe the GPCRs, as they embrace a group of families for which there are indications of evolutionary relationship, but between which there is no statistically significant similarity in sequence []. The currently known clan members include rhodopsin-like GPCRs (Class A, GPCRA), secretin-like GPCRs (Class B, GPCRB), metabotropic glutamate receptor family (Class C, GPCRC), fungal mating pheromone receptors (Class D, GPCRD), cAMP receptors (Class E, GPCRE) and frizzled/smoothened (Class F, GPCRF) [, , , , ]. GPCRs are major drug targets, and are consequently the subject of considerable research interest. It has been reported that the repertoire of GPCRs for endogenous ligands consists of approximately 400 receptors in humans and mice []. Most GPCRs are identified on the basis of their DNA sequences, rather than the ligand they bind, those that are unmatched to known natural ligands are designated by as orphan GPCRs, or unclassified GPCRs [].The rhodopsin-like GPCRs (GPCRA) represent a widespread protein family that includes hormone, neurotransmitter and light receptors, all of which transduce extracellular signals through interaction with guanine nucleotide-binding (G) proteins. Although their activating ligands vary widely in structure and character, the amino acid sequences of the receptors are very similar and are believed to adopt a common structural framework comprising 7 transmembrane (TM) helices [, , ].Vasopressin and oxytocin are members of the neurohypophyseal hormone familyfound in all mammalian species. They are present at high levels in theposterior pituitary. Vasopressin has an essential role in the control ofthe water content of the body, acting in the kidney to increase water andsodium absorption. In higher concentrations, vasopressin stimulatescontraction of vascular smooth muscle, stimulates glycogen breakdown in theliver, induces platelet activation, and evokes release of corticotrophinfrom the anterior pituitary. Vasopressin and its analogues are usedclinically to treat diabetes insipidus.The V2 receptor is found in high levels in the osmoregulatory epithelia ofthe terminal urinary tract, where it stimulates water reabsorption. Itis also present in lower levels in the endothelium and blood vessels of somespecies, where it induces vasodilation. In the CNS, binding sites arefound in the subiculum, with lower levels in caudate-putamen and islandsof Calleja. The receptor is involved in an effector pathway that formscAMP through activation of G proteins. |
