The renal plumbing system: aquaporin water channels.
Aquaporins are channels that facilitate movement of water across lipid bilayers. They are expressed in multiple tissues and are essential for regulation of body water homeostasis. The kidney is the main organ responsible for this regulation, and at least seven aquaporins are expressed at distinct sites in the kidney. Aquaporin expression correlates with observed water permeability of each nephron segment: proximal tubule and descending thin limb of Henle have constitutive high water permeability due to expression of AQP1, whereas collecting duct water permeability is tightly regulated by the antidiuretic hormone vasopressin via regulation of AQP2. This review aims at providing insight into renal aquaporins, with special focus on AQP2.
Nejsum
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Department of Molecular and Cellular Physiology, Beckman Center for Molecular and Genetic Medicine, B107, Stanford University School of Medicine, 279 Campus Drive, Stanford, California 94305-5435, USA. nejsum@stanford.edu
D000818:Animals; D051399:Aquaporin 2; D020346:Aquaporins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D001834:Body Water / Q000378:metabolism*; D003919:Diabetes Insipidus / Q000235:genetics; D006801:Humans; D007668:Kidney / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D014667:Vasopressins / Q000502:physiology
C496023:AQP2 protein, human; C496024:Aqp2 protein, mouse; D051399:Aquaporin 2; D020346:Aquaporins; D014667:Vasopressins