Yeast reveals unexpected roles and regulatory features of aquaporins and aquaglyceroporins.
BACKGROUND
The yeast Saccharomyces cerevisiae provides unique opportunities to study roles and regulation of aqua/glyceroporins using frontline tools of genetics and genomics as well as molecular cell and systems biology.


METHODS
S. cerevisiae has two similar orthodox aquaporins. Based on phenotypes mediated by gene deletion or overexpression as well as on their expression pattern, the yeast aquaporins play important roles in key aspects of yeast biology: establishment of freeze tolerance, during spore formation as well as determination of cell surface properties for substrate adhesion and colony formation. Exactly how the aquaporins perform those roles and the mechanisms that regulate their function under such conditions remain to be elucidated. S. cerevisiae also has two different aquaglyceroporins. While the role of one of them, Yfl054c, remains to be determined, Fps1 plays critical roles in osmoregulation by controlling the accumulation of the osmolyte glycerol. Fps1 communicates with two osmo-sensing MAPK signalling pathways to perform its functions but the details of Fps1 regulation remain to be determined.


CONCLUSIONS
Several phenotypes associated with aqua/glyceroporin function in yeasts have been established. However, how water and glycerol transport contribute to the observed effects is not understood in detail. Also many of the basic principles of regulation of yeast aqua/glyceroporins remain to be elucidated.


CONCLUSIONS
Studying the yeast aquaporins and aquaglyceroporins offers rich insight into the life style, evolution and adaptive responses of yeast and rewards us with discoveries of unexpected roles and regulatory mechanisms of members of this ancient protein family. This article is part of a Special Issue entitled Aquaporins.
Department of Chemistry and Molecular Biology, University of Gothenburg, Sweden.
Doryaneh
D
Ahmadpour
Department of Chemistry and Molecular Biology, University of Gothenburg, Sweden.
Cecilia
C
Geijer
Department of Chemistry and Molecular Biology, University of Gothenburg, Sweden.
Markus J
MJ
Tamás
Experimental Medical Science, Medical Structural biology, Lund University, Sweden.
Karin
K
Lindkvist-Petersson
Department of Chemistry and Molecular Biology, University of Gothenburg, Sweden. Electronic address: stefan.hohmann@gu.se.
Stefan
S
Hohmann
D000222:Adaptation, Physiological / Q000502:physiology; D000595:Amino Acid Sequence; D051397:Aquaglyceroporins / Q000737:chemistry / Q000502:physiology*; D020346:Aquaporins / Q000737:chemistry / Q000502:physiology*; D005615:Freezing; D008969:Molecular Sequence Data; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*
D051397:Aquaglyceroporins; D020346:Aquaporins; D029701:Saccharomyces cerevisiae Proteins
Aquaporin; Freeze tolerance; MAPK pathway; Osmoregulation; Signal transduction; Stress resistance