Characterization of human aquaporin ion channels in a yeast expression system as a tool for novel ion channel discovery.

Autor:	Nourmohammadi S; School of Biomedicine, Faculty of Health and Medical Sciences, and the Institute for Photonics and Advanced Sensing, University of Adelaide, Adelaide, SA 5005, Australia., Henderson SW; School of Biomedicine, Faculty of Health and Medical Sciences, and the Institute for Photonics and Advanced Sensing, University of Adelaide, Adelaide, SA 5005, Australia., Ramesh SA; Biological Sciences, College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia., Yool AJ; School of Biomedicine, Faculty of Health and Medical Sciences, and the Institute for Photonics and Advanced Sensing, University of Adelaide, Adelaide, SA 5005, Australia.
Jazyk:	angličtina
Zdroj:	Bioscience reports [Biosci Rep] 2024 Aug 28; Vol. 44 (8).
DOI:	10.1042/BSR20240542
Abstrakt:	Aquaporin (AQP) channels found in all domains of life are transmembrane proteins which mediate passive transport of water, glycerol, signaling molecules, metabolites, and charged solutes. Discovery of new classes of ion-conducting AQP channels has been slow, likely reflecting time- and labor-intensive methods required for traditional electrophysiology. Work here defines a sensitive mass-throughput system for detecting AQP ion channels, identified by rescue of cell growth in the K+-transport-defective yeast strain CY162 following genetic complementation with heterologously expressed cation-permeable channels, using the well characterized human AQP1 channel for proof of concept. Results showed AQP1 conferred transmembrane permeability to cations which rescued survival in CY162 yeast. Comprehensive testing showed that growth response properties fully recapitulated AQP1 pharmacological agonist and antagonist profiles for activation, inhibition, dose-dependence, and structure-function relationships, demonstrating validity of the yeast screening tool for AQP channel identification and drug discovery efforts. This method also provided new information on divalent cation blockers of AQP1, pH sensitivity of antagonists, and ion permeability of human AQP6. Site-directed mutagenesis of AQP1 channel regulatory domains confirmed that yeast growth rescue was mediated by the introduced channels. Optical monitoring with a lithium-sensitive photoswitchable probe in living cells independently demonstrated monovalent cation permeability of AQP1 channels in yeast plasma membrane. Ion channel properties of AQP1 expressed in yeast were consistent with those of AQP1 expressed in Xenopus laevis oocyte and K+-transport defective Escherichia coli. Outcomes here establish a powerful new approach for efficient screening of phylogenetically diverse AQPs for yet untested functions as cation channels. (© 2024 The Author(s).)
Databáze:	MEDLINE
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