Conditional osmotic stress in yeast: a system to study transport through aquaglyceroporins and osmostress signaling

Sara Karlgren, Nina Pettersson, Bodil Nordlander, John C. Mathai, Jeffrey L. Brodsky, Mark L. Zeidel, Roslyn M. Bill, Stefan Hohmann*

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

The accumulation and transport of solutes are hallmarks of osmoadaptation. In this study we have employed the inability of the Saccharomyces cerevisiae gpd1Δ gpd2Δ mutant both to produce glycerol and to adapt to high osmolarity to study solute transport through aquaglyceroporins and the control of osmostress-induced signaling. High levels of different polyols, including glycerol, inhibited growth of the gpd1Δ gpd2Δ mutant. This growth inhibition was suppressed by expression of the hyperactive allele Fps1-AΔ of the osmogated yeast aquaglyceroporin, Fps1. The degree of suppression correlated with the relative rate of transport of the different polyols tested. Transport studies in secretory vesicles confirmed that Fps1-Δ1 transports polyols at increased rates compared with wild type Fps1. Importantly, wild type Fps1 and Fps1-Δ1 showed similarly low permeability for water. The growth defect on polyols in the gpd1Δ gpd2Δ mutant was also suppressed by expression of a heterologous aquaglyceroporin, rat AQP9. We surmised that this suppression was due to polyol influx, causing the cells to passively adapt to the stress. Indeed, when aquaglyceroporin-expressing gpd1Δ gpd2Δ mutants were treated with glycerol, xylitol, or sorbitol, the osmosensing HOG pathway was activated, and the period of activation correlated with the apparent rate of polyol uptake. This observation supports the notion that deactivation of the HOG pathway is closely coupled to osmotic adaptation. Taken together, our "conditional" osmotic stress system facilitates studies on aquaglyceroporin function and reveals features of the osmosensing and signaling system. © 2005 by The American Society for Biochemistry and Molecular Biology, Inc.

Original languageEnglish
Pages (from-to)7186-7193
Number of pages8
JournalJournal of Biological Chemistry
Volume280
Issue number8
Early online date17 Dec 2004
DOIs
Publication statusPublished - 25 Feb 2005

Bibliographical note

© 2005 The American Society for Biochemistry and Molecular Biology, Inc.

Keywords

  • biological transport
  • kinetics
  • mutation
  • osmotic pressure
  • porins
  • saccharomyces cerevisiae
  • signal transduction
  • sugar alcohols

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    Karlgren, S., Pettersson, N., Nordlander, B., Mathai, J. C., Brodsky, J. L., Zeidel, M. L., Bill, R. M., & Hohmann, S. (2005). Conditional osmotic stress in yeast: a system to study transport through aquaglyceroporins and osmostress signaling. Journal of Biological Chemistry, 280(8), 7186-7193. https://doi.org/10.1074/jbc.M413210200