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oai:recercat.cat:20.500.12327/22392025-10-22T11:27:15Zcom_2072_4428com_2072_4427col_2072_487898

2025-10-22T11:27:15Z urn:hdl:20.500.12327/2239 The pH sensitivity of Aqp0 channels in tetraploid and diploid teleosts Chauvigné, François Zapater, Cinta Stavang, Jon Anders Taranger, Geir Lasse Cerdà, Joan Finn, Roderick Nigel Producció Animal Aqüicultura Water homeostasis and the structural integrity of the vertebrate lens is partially mediated by AQP0 channels. Emerging evidence indicates that external pH may be involved in channel gating. Here we show that a tetraploid teleost, the Atlantic salmon, retains 4 aqp0 genes (aqp0a1, -0a2, -0b1, and -0b2), which are highly, but not exclusively, expressed in the lens. Functional characterization reveals that,although each paralog permeateswater efficiently, the permeability is respectively shifted to the neutral, alkaline, or acidic pH in Aqp0a1, -0a2, and -0b1, whereas that of Aqp0b2 is not regulated by external pH. Mutagenesis studies demonstrate that Ser38, His39, and His40 residues in the extracellular transmembrane domain of a-helix 2 facing the water pore are critical for the pH modulation of water transport. To validate these findings, we show that both zebrafish Aqp0a and -0b are functional water channels with respective pH sensitivities toward alkaline or acid pH ranges and that an N-terminal allelic variant (Ser19) of Aqp0b exists that abolishes water transport in Xenopus laevis oocytes. The data suggest that the alkaline pH sensitivity is a conserved trait in teleost Aqp0 a-type channels, whereas mammalian AQP0 and some teleost Aqp0 b-type channels display an acidic pH permeation preference. 2025-10-22T11:27:15Z 2025-10-22T11:27:15Z 2015-02-09 info:eu-repo/semantics/article Chauvigne, François, Cinta Zapater, Jon Anders Stavang, Geir Lasse Taranger, Joan Cerda, and Roderick Nigel Finn. 2015. “The pH sensitivity of Aqp0 channels in tetraploid and diploid teleosts”. FASEB Journal 29(5). doi:10.1096/fj.14-267625 0892-6638 http://hdl.handle.net/20.500.12327/2239 https://doi.org/10.1096/fj.14-267625 eng FASEB Journal MICINN/Programa Nacional de Proyectos de Investigación Fundamental/AGL2010-15597/ES/AQUAPORINAS TESTICULARES DURANTE LA ESPERMATOGENESIS DE PECES MARINOS Y LA ACTIVACION Y PERMEABILIDAD ESPERMATICA/ http://creativecommons.org/licenses/by-nc/4.0/ info:eu-repo/semantics/openAccess Attribution-NonCommercial 4.0 International Wiley Open Access