Expression of heterologous aquaporins for functional analysis in Saccharomyces cerevisiae
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In this study the yeast Saccharomyces cerevisiae, which is a genetically tractable model for analysis of osmoregulation, has been used for analysis of heterologous aquaporins. Aquaporin water channels play important roles in the control of water homeostasis in individual cells and multicellular organisms. We have investigated the effects of functional expression of the mammalian aquaporins AQP1 and AQP5 and the aquaglyceroporins AQP3 and AQP9. Expression of aquaporins caused moderate growth inhibition under hyperosmotic stress, while expression of aquaglyceroporins mediated strong growth inhibition due to glycerol loss. Water transport was monitored in protoplasts, where the kinetics of bursting was influenced by presence of aquaporins but not aquaglyceroporins. We observed glycerol transport through aquaglyceroporins, but not aquaporins, in a yeast strain deficient in glycerol production, whose growth depends on glycerol inflow. In addition, a gene reporter assay allowed to indirectly monitor the effect of AQP9-mediated enhanced glycerol loss on osmoadaptation. Transport activity of certain aqua(glycero)porins was diminished by low pH or CuSO4, suggesting that yeast can potentially be used for screening of putative aquaporin inhibitors. We conclude that yeast is a versatile system for functional studies of aquaporins, and it can be developed to screen for compounds of potential pharmacological use.
KeywordsWater transport Glycerol Aquaglyceroporin Inhibitors Yeast Osmoadaptation
- Albertyn J, Hohmann S, Thevelein JM, Prior BA (1994) GPD1, which encodes glycerol-3-phosphate dehydrogenase, is essential for growth under osmotic stress in Saccharomyces cerevisiae, and its expression is regulated by the high-osmolarity glycerol response pathway. Mol Cell Biol 14:4135–4144PubMedGoogle Scholar
- Hohmann S, Nielsen S, Agre P (eds) (2001) Aquaporins. AcademicGoogle Scholar
- Pahlman AK, Granath K, Ansell R, Hohmann S, Adler L (2001) The yeast glycerol 3-phosphatases Gpp1p and Gpp2p are required for glycerol biosynthesis and differentially involved in the cellular responses to osmotic, anaerobic, and oxidative stress. J Biol Chem 276:3555–3563PubMedCrossRefGoogle Scholar