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Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Minireview cung cấp cho các bạn kiến thức về ngành y đề tài: The aquaporins. | Protein family review The aquaporins Elisabeth Kruse Norbert Uehlein and Ralf Kaldenhoff Address Institute of Botany Department of Applied Plant Sciences Darmstadt University of Technology SchnittspahnstraBe 10 D-64287 Darmstadt Germany. Correspondence Ralf Kaldenhoff. Email kaldenhoff@bio.tu-darmstadt.de Published 28 February 2006 Genome Biology 2006 7 206 doi l0.ll86 gb-2006-7-2-206 The electronic version of this article is the complete one and can be found online at http genomebiology.com 2006 7 2 206 2006 BioMed Central Ltd Summary Water is the major component of all living cells and efficient regulation of water homeostasis is essential for many biological processes. The mechanism by which water passes through biological membranes was a matter of debate until the discovery of the aquaporin water channels. Aquaporins are intrinsic membrane proteins characterized by six transmembrane helices that selectively allow water or other small uncharged molecules to pass along the osmotic gradient. In addition recent observations show that some aquaporins also facilitate the transport of volatile substances such as carbon dioxide CO2 and ammonia NH3 across membranes. Aquaporins usually form tetramers with each monomer defining a single pore. Aquaporin-related proteins are found in all organisms from archaea to mammals. In both uni- and multicellular organisms numerous isoforms have been identified that are differentially expressed and modified by post-translational processes thus allowing fine-tuned tissue-specific osmoregulation. In mammals aquaporins are involved in multiple physiological processes including kidney and salivary gland function. They are associated with several clinical disorders such as kidney dysfunction loss of vision and brain edema. Gene organization and evolutionary history The aquaporins are a family of small 24-30 kDa poreforming integral membrane proteins. This ancient protein family was first named after its archetype the major intrinsic .
