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It is the only aquaporin regulated by vasopressin.[1]
The basic job of aquaporin 2 is to reabsorb water from the urine while its being removed from the blood by the kidney. Aquaporin 2 is in kidney epithelial cells and usually lies dormant in intracellular vesicle membranes. When it is needed, vasopressin binds to the cell surface vasopressin receptor thereby activating a signaling pathway that causes the aquaporin 2 containing vesicles to fuse with the plasma membrane, so the aquaporin 2 can be used by the cell.[2]
This aquaporin is regulated in two ways by the peptide hormonevasopressin:
short-term regulation (minutes) through trafficking of AQP2 vesicles to the apical region where they fuse with the apical plasma membrane
long-term regulation (days) through an increase in AQP2 gene expression.
This aquaporin is also regulated by food intake. Fasting reduces expression of this aquaporin independently of vasopressin.
Clinical significance
Mutations in this channel are associated with nephrogenic diabetes insipidus, which can be autosomal dominant or recessive. Mutations in the vasopressin receptor cause a similar X-linked phenotype.
Lithium, which is often used to treat bipolar disorder, can cause acquired diabetes insipidus (characterized by the excretion of large volumes of dilute urine) by decreasing the expression of the AQP2 gene.
The expression of the AQP2 gene is increased during conditions associated with water retention such as pregnancy and congestive heart failure.
↑Dibas AI, Mia AJ, Yorio T (December 1998). "Aquaporins (water channels): role in vasopressin-activated water transport". Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine. 219 (3): 183–99. doi:10.3181/00379727-219-44332. PMID9824541.
↑Lodish H, Berk A, Kaiser CA, Krieger M, Scott MP, Bretscher A, Ploegh H, Matsudaira P (2008). Molecular Cell Biology (6th ed.). New York: Freeman. p. 445. ISBN978-0-7167-7601-7.
Robben JH, Knoers NV, Deen PM (August 2006). "Cell biological aspects of the vasopressin type-2 receptor and aquaporin 2 water channel in nephrogenic diabetes insipidus". American Journal of Physiology. Renal Physiology. 291 (2): F257–70. doi:10.1152/ajprenal.00491.2005. PMID16825342.
Deen PM, Weghuis DO, Sinke RJ, Geurts van Kessel A, Wieringa B, van Os CH (1994). "Assignment of the human gene for the water channel of renal collecting duct Aquaporin 2 (AQP2) to chromosome 12 region q12-->q13". Cytogenetics and Cell Genetics. 66 (4): 260–2. doi:10.1159/000133707. PMID7512890.
Uchida S, Sasaki S, Fushimi K, Marumo F (September 1994). "Isolation of human aquaporin-CD gene". The Journal of Biological Chemistry. 269 (38): 23451–5. PMID7522228.
Saito F, Sasaki S, Chepelinsky AB, Fushimi K, Marumo F, Ikeuchi T (1994). "Human AQP2 and MIP genes, two members of the MIP family, map within chromosome band 12q13 on the basis of two-color FISH". Cytogenetics and Cell Genetics. 68 (1–2): 45–8. doi:10.1159/000133885. PMID7525161.
Brown D (May 2003). "The ins and outs of aquaporin-2 trafficking". American Journal of Physiology. Renal Physiology. 284 (5): F893–901. doi:10.1152/ajprenal.00387.2002. PMID12676734.
Maruyama K, Sugano S (January 1994). "Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides". Gene. 138 (1–2): 171–4. doi:10.1016/0378-1119(94)90802-8. PMID8125298.
Deen PM, Verdijk MA, Knoers NV, Wieringa B, Monnens LA, van Os CH, van Oost BA (April 1994). "Requirement of human renal water channel aquaporin-2 for vasopressin-dependent concentration of urine". Science. 264 (5155): 92–5. doi:10.1126/science.8140421. PMID8140421.
Oksche A, Möller A, Dickson J, Rosendahl W, Rascher W, Bichet DG, Rosenthal W (November 1996). "Two novel mutations in the aquaporin-2 and the vasopressin V2 receptor genes in patients with congenital nephrogenic diabetes insipidus". Human Genetics. 98 (5): 587–9. doi:10.1007/s004390050264. PMID8882880.
Mulders SM, Knoers NV, Van Lieburg AF, Monnens LA, Leumann E, Wühl E, Schober E, Rijss JP, Van Os CH, Deen PM (February 1997). "New mutations in the AQP2 gene in nephrogenic diabetes insipidus resulting in functional but misrouted water channels". Journal of the American Society of Nephrology. 8 (2): 242–8. PMID9048343.
Ma T, Yang B, Umenishi F, Verkman AS (August 1997). "Closely spaced tandem arrangement of AQP2, AQP5, and AQP6 genes in a 27-kilobase segment at chromosome locus 12q13". Genomics. 43 (3): 387–9. doi:10.1006/geno.1997.4836. PMID9268644.
Canfield MC, Tamarappoo BK, Moses AM, Verkman AS, Holtzman EJ (October 1997). "Identification and characterization of aquaporin-2 water channel mutations causing nephrogenic diabetes insipidus with partial vasopressin response". Human Molecular Genetics. 6 (11): 1865–71. doi:10.1093/hmg/6.11.1865. PMID9302264.
Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K, Suyama A, Sugano S (October 1997). "Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library". Gene. 200 (1–2): 149–56. doi:10.1016/S0378-1119(97)00411-3. PMID9373149.
Vargas-Poussou R, Forestier L, Dautzenberg MD, Niaudet P, Déchaux M, Antignac C (December 1997). "Mutations in the vasopressin V2 receptor and aquaporin-2 genes in 12 families with congenital nephrogenic diabetes insipidus". Journal of the American Society of Nephrology. 8 (12): 1855–62. PMID9402087.
Kuwahara M (February 1998). "Aquaporin-2, a vasopressin-sensitive water channel, and nephrogenic diabetes insipidus". Internal Medicine. 37 (2): 215–7. doi:10.2169/internalmedicine.37.215. PMID9550615.
Goji K, Kuwahara M, Gu Y, Matsuo M, Marumo F, Sasaki S (September 1998). "Novel mutations in aquaporin-2 gene in female siblings with nephrogenic diabetes insipidus: evidence of disrupted water channel function". The Journal of Clinical Endocrinology and Metabolism. 83 (9): 3205–9. doi:10.1210/jc.83.9.3205. PMID9745427.
Saito T, Ishikawa S, Ito T, Oda H, Ando F, Higashiyama M, Nagasaka S, Hieda M, Saito T (June 1999). "Urinary excretion of aquaporin-2 water channel differentiates psychogenic polydipsia from central diabetes insipidus". The Journal of Clinical Endocrinology and Metabolism. 84 (6): 2235–7. doi:10.1210/jc.84.6.2235. PMID10372737.