Gazzarrini Sabrina, Kang Ming, Epimashko Svetlana, Van Etten James L, Dainty Jack, Thiel Gerhard, Moroni Anna
Dipartimento di Biologia and Istituto di Biofisica-Consiglio Nazionale delle Ricerche, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy.
Proc Natl Acad Sci U S A. 2006 Apr 4;103(14):5355-60. doi: 10.1073/pnas.0600848103. Epub 2006 Mar 28.
Fast and selective transport of water through cell membranes is facilitated by water channels. Water channels belonging to the major intrinsic proteins (MIPs) family have been found in all three domains of life, Archaea, Bacteria, and Eukarya. Here we show that Chlorella virus MT325 has a water channel gene, aqpv1, that forms a functional aquaglyceroporin in oocytes. aqpv1 is transcribed during infection together with MT325 kcv, a gene encoding a previously undescribed type of viral potassium channel. Coexpression of AQPV1 and MT325-Kcv in Xenopus oocytes synergistically increases water transport, suggesting a possible concerted action of the two channels in the infection cycle. The two channels operate by a thermodynamically coupled mechanism that simultaneously alters water conductance and driving force for water movement. Considering the universal role of osmosis, this mechanism is relevant to any cell coexpressing water and potassium channels and could have pathological as well as basic physiological relevance.
水通道促进了水在细胞膜上的快速和选择性运输。属于主要内在蛋白（MIPs）家族的水通道已在古菌、细菌和真核生物这三个生命域中被发现。在此我们表明，小球藻病毒MT325拥有一个水通道基因aqpv1，其在卵母细胞中形成功能性水甘油通道蛋白。aqpv1在感染过程中与MT325 kcv一起转录，MT325 kcv是一个编码此前未描述的病毒钾通道类型的基因。AQPV1和MT325-Kcv在非洲爪蟾卵母细胞中的共表达协同增加了水运输，表明这两个通道在感染周期中可能协同作用。这两个通道通过一种热力学耦合机制运作，该机制同时改变水导率和水移动的驱动力。考虑到渗透作用的普遍作用，这种机制与任何共表达水通道和钾通道的细胞相关，并且可能具有病理以及基础生理学意义。
