Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The high water permeability characteristic of mammalian red cell membranes is now known to be caused by the protein AQP1. This channel freely permits movement of water across the cell membrane, but it is not permeated by other small, uncharged molecules or charged solutes. AQP1 is a tetramer with each subunit containing an aqueous pore likened to an hourglass formed by obversely arranged tandem repeats. Cryoelectron microscopy of reconstituted AQP1 membrane crystals has revealed the three-dimensional structure at 3-6 A. AQP1 is distributed in apical and basolateral membranes of renal proximal tubules and descending thin limbs as well as capillary endothelia. Ten mammalian aquaporins have been identified in water-permeable tissues and fall into two groupings. Orthodox aquaporins are water-selective and include AQP2, a vasopressin-regulated water channel in renal collecting duct, in addition to AQP0, AQP4, and AQP5. Multifunctional aquaglyceroporins AQP3, AQP7, and AQP9 are permeated by water, glycerol, and some other solutes. Aquaporins are being defined in numerous other species including amphibia, insects, plants, and microbials. Members of the aquaporin family are implicated in numerous physiological processes as well as the pathophysiology of a wide range of clinical disorders.
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PMID:Cellular and molecular biology of the aquaporin water channels. 1087 56

Aquaporins (AQP) are integral membrane proteins that serve as channels in the transfer of water, and in some cases, small solutes across the membrane. They are conserved in bacteria, plants, and animals. Structural analyses of the molecules have revealed the presence of a pore in the center of each aquaporin molecule. In mammalian cells, more than 10 isoforms (AQP0-AQP10) have been identified so far. They are differentially expressed in many types of cells and tissues in the body. AQP0 is abundant in the lens. AQP1 is found in the blood vessels, kidney proximal tubules, eye, and ear. AQP2 is expressed in the kidney collecting ducts, where it shuttles between the intracellular storage sites and the plasma membrane under the control of antidiuretic hormone (ADH). Mutations of AQP2 result in diabetes insipidus. AQP3 is present in the kidney collecting ducts, epidermis, urinary, respiratory, and digestive tracts. AQP3 in organs other than the kidney may be involved in the supply of water to them. AQP4 is present in the brain astrocytes, eye, ear, skeletal muscle, stomach parietal cells, and kidney collecting ducts. AQP5 is in the secretory cells such as salivary, lacrimal, and sweat glands. AQP5 is also expressed in the ear and eye. AQP6 is localized intracellular vesicles in the kidney collecting duct cells. AQP7 is expressed in the adipocytes, testis, and kidney. AQP8 is expressed in the kidney, testis, and liver. AQP9 is present in the liver and leukocytes. AQP10 is expressed in the intestine. The diverse and characteristic distribution of aquaporins in the body suggests their important and specific roles in each organ.
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PMID:Aquaporins: water channel proteins of the cell membrane. 1524 1

Aquaporin 4 (AQP4) is abundantly expressed in the perivascular glial endfeet in the central nervous system (CNS), where it is involved in the exchange of fluids between blood and brain. At this location, AQP4 contributes to the formation and/or the absorption of the brain edema that may arise following pathologies such as brain injuries, brain tumours, and cerebral ischemia. As vasopressin and its G-protein-coupled receptor (V1(a)R) have been shown to affect the outcome of brain edema, we have investigated the regulatory interaction between AQP4 and V1(a)R by heterologous expression in Xenopus laevis oocytes. The water permeability of AQP4/V1(a)R-expressing oocytes was reduced in a vasopressin-dependent manner, as a result of V1(a)R-dependent internalization of AQP4. Vasopressin-dependent internalization was not observed in AQP9/V1(a)R-expressing oocytes. The regulatory interaction between AQP4 and V1(a)R involves protein kinase C (PKC) activation and is reduced upon mutation of Ser(180) on AQP4 to an alanine. Thus, the present study demonstrates at the molecular level a functional link between the vasopressin receptor V1(a)R and AQP4. This functional interaction between AQP4 and V1(a)R may prove to be a potential therapeutic target in the prevention and treatment of brain edema.
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PMID:Vasopressin-dependent short-term regulation of aquaporin 4 expressed in Xenopus oocytes. 1980 Sep 50