Aquaporin-1 Explained

Aquaporin 1 (AQP-1) is a protein that in humans is encoded by the AQP1 gene.

AQP-1 is a widely expressed water channel, whose physiological function has been most thoroughly characterized in the kidney. It is found in the basolateral and apical plasma membranes of the proximal tubules, the descending limb of the loop of Henle, and in the descending portion of the vasa recta. Additionally, it is found in red blood cells, vascular endothelium, the gastrointestinal tract, sweat glands, lungs, and the central nervous system.^[1]

Neural AQP-1 receptors are regulated by vasopressin AVPR1A receptor activity.^[2]

Function

Aquaporins are a family of small integral membrane proteins related to the major intrinsic protein (MIP or AQP0). This gene encodes an aquaporin which functions as both a molecular water channel protein and as a non-selective cation channel gated by cyclic guanosine monophosphate (cGMP).^[3] It is a homotetramer with six bilayer spanning domains and N-glycosylation sites. The AQP1 monomer consists of six transmembrane alpha helices that are connected by five loops (A to E).^[4] The protein physically resembles channel proteins and is abundant in erythrocytes and renal tubes. The gene encoding this aquaporin is a possible candidate for disorders involving imbalance in ocular fluid movement.^[5]

See also

• Aquaporin
• Colton antigen system

Further reading

• Knepper MA . The aquaporin family of molecular water channels . Proceedings of the National Academy of Sciences of the United States of America . 91 . 14 . 6255–8 . July 1994 . 7517546 . 44179 . 10.1073/pnas.91.14.6255 . 1994PNAS...91.6255K . free .
• Borgnia M, Nielsen S, Engel A, Agre P . Cellular and molecular biology of the aquaporin water channels . Annual Review of Biochemistry . 68 . 425–58 . 2000 . 10872456 . 10.1146/annurev.biochem.68.1.425 .
• Horster M . Embryonic epithelial membrane transporters . American Journal of Physiology. Renal Physiology . 279 . 6 . F982-96 . December 2000 . 11097616 . 10.1152/ajprenal.2000.279.6.F982 . 33398595 .
• Yool AJ, Weinstein AM . New roles for old holes: ion channel function in aquaporin-1 . News in Physiological Sciences . 17 . 2 . 68–72 . April 2002 . 11909995 . 10.1152/nips.01372.2001 . 36525343 .
• Book: 10.1002/0470868759.ch4 . The Architecture of a Water-Selective Pore in the Lipid Bilayer Visualized by Electron Crystallography in Vitreous Ice . Ion Channels: From Atomic Resolution Physiology to Functional Genomics . Novartis Foundation Symposia . 2008 . Mitra . Alok K. . Ren . Gang . Reddy . Vijay S. . Cheng . Anchi . Froger . Alexandrine . 33–50 . 978-0-470-84375-8 .
• Ripoche P, Goossens D, Devuyst O, Gane P, Colin Y, Verkman AS, Cartron JP . Role of RhAG and AQP1 in NH3 and CO2 gas transport in red cell ghosts: a stopped-flow analysis . Transfusion Clinique et Biologique . 13 . 1–2 . 117–22 . 2006 . 16574458 . 10.1016/j.tracli.2006.03.004 .
• Preston GM, Carroll TP, Guggino WB, Agre P . Appearance of water channels in Xenopus oocytes expressing red cell CHIP28 protein . Science . 256 . 5055 . 385–7 . April 1992 . 1373524 . 10.1126/science.256.5055.385 . 8550043 . 1992Sci...256..385P .
• Preston GM, Agre P . Isolation of the cDNA for erythrocyte integral membrane protein of 28 kilodaltons: member of an ancient channel family . Proceedings of the National Academy of Sciences of the United States of America . 88 . 24 . 11110–4 . December 1991 . 1722319 . 53083 . 10.1073/pnas.88.24.11110 . 1991PNAS...8811110P . free .
• Smith BL, Agre P . Erythrocyte Mr 28,000 transmembrane protein exists as a multisubunit oligomer similar to channel proteins . The Journal of Biological Chemistry . 266 . 10 . 6407–15 . April 1991 . 10.1016/S0021-9258(18)38133-X . 2007592 . free .
• Denker BM, Smith BL, Kuhajda FP, Agre P . Identification, purification, and partial characterization of a novel Mr 28,000 integral membrane protein from erythrocytes and renal tubules . The Journal of Biological Chemistry . 263 . 30 . 15634–42 . October 1988 . 10.1016/S0021-9258(19)37635-5 . 3049610 . free .
• Zelinski T, Kaita H, Lewis M, Coghlan G, Philipps S, Belcher E, McAlpine PJ, Coopland G, Wong P . 6 . The Colton blood group locus. A linkage analysis . Transfusion . 28 . 5 . 435–8 . 1988 . 3166547 . 10.1046/j.1537-2995.1988.28588337331.x . 35893178 .
• Preston GM, Jung JS, Guggino WB, Agre P . Membrane topology of aquaporin CHIP. Analysis of functional epitope-scanning mutants by vectorial proteolysis . The Journal of Biological Chemistry . 269 . 3 . 1668–73 . January 1994 . 10.1016/S0021-9258(17)42079-5 . 7507481 . free .
• Skach WR, Shi LB, Calayag MC, Frigeri A, Lingappa VR, Verkman AS . Biogenesis and transmembrane topology of the CHIP28 water channel at the endoplasmic reticulum . The Journal of Cell Biology . 125 . 4 . 803–15 . May 1994 . 7514605 . 2120064 . 10.1083/jcb.125.4.803 .
• Li X, Yu H, Koide SS . The water channel gene in human uterus . Biochemistry and Molecular Biology International . 32 . 2 . 371–7 . February 1994 . 7517253 .
• Walz T, Smith BL, Agre P, Engel A . The three-dimensional structure of human erythrocyte aquaporin CHIP . The EMBO Journal . 13 . 13 . 2985–93 . July 1994 . 7518771 . 395186 . 10.1002/j.1460-2075.1994.tb06597.x .
• Preston GM, Smith BL, Zeidel ML, Moulds JJ, Agre P . Mutations in aquaporin-1 in phenotypically normal humans without functional CHIP water channels . Science . 265 . 5178 . 1585–7 . September 1994 . 7521540 . 10.1126/science.7521540 . 1994Sci...265.1585P .
• Smith BL, Preston GM, Spring FA, Anstee DJ, Agre P . Human red cell aquaporin CHIP. I. Molecular characterization of ABH and Colton blood group antigens . The Journal of Clinical Investigation . 94 . 3 . 1043–9 . September 1994 . 7521882 . 295159 . 10.1172/JCI117418 .
• van Hoek AN, Wiener MC, Verbavatz JM, Brown D, Lipniunas PH, Townsend RR, Verkman AS . Purification and structure-function analysis of native, PNGase F-treated, and endo-beta-galactosidase-treated CHIP28 water channels . Biochemistry . 34 . 7 . 2212–9 . February 1995 . 7532004 . 10.1021/bi00007a015 .
• Keen TJ, Inglehearn CF, Patel RJ, Green ED, Peluso DC, Bhattacharya SS . Localization of the aquaporin 1 (AQP1) gene within a YAC contig containing the polymorphic markers D7S632 and D7S526 . Genomics . 25 . 2 . 599–600 . January 1995 . 7540589 . 10.1016/0888-7543(95)80070-3 .

External links

• • Gallery of Aquaporin Simulations

Notes and References

1. 2923372 . 2010 . Francesca . B. . Rezzani . R. . Aquaporin and Blood Brain Barrier . Current Neuropharmacology . 8 . 2 . 92–96 . 10.2174/157015910791233132 . 21119879 .
2. Rauen K, Pop V, Trabold R, Badaut J, Plesnila N . Vasopressin V1a Receptors Regulate Cerebral Aquaporin 1 after Traumatic Brain Injury . Journal of Neurotrauma . 37 . 4 . 665–674 . February 2020 . 31547764 . 7045352 . 10.1089/neu.2019.6653 .
3. Boassa D, Yool AJ . Single amino acids in the carboxyl terminal domain of aquaporin-1 contribute to cGMP-dependent ion channel activation . BMC Physiology . 3 . 12 . October 2003 . 14561230 . 269983 . 10.1186/1472-6793-3-12 . free .
4. Kong Y, Ma J . Dynamic mechanisms of the membrane water channel aquaporin-1 (AQP1) . Proceedings of the National Academy of Sciences of the United States of America . 98 . 25 . 14345–9 . December 2001 . 11717407 . 64684 . 10.1073/pnas.251507998 . 2001PNAS...9814345K . free .
5. Web site: Entrez Gene: AQP1 aquaporin 1 (Colton blood group).