Fps1p controls the accumulation and release of the compatible solute glycerol in yeast osmoregulation.
Journal article, 1999
The accumulation of compatible solutes, such as glycerol, in the yeast Saccharomyces cerevisiae, is a ubiquitous mechanism in cellular osmoregulation. Here, we demonstrate that yeast cells control glycerol accumulation in part via a regulated, Fps1p-mediated export of glycerol. Fps1p is a member of the MIP family of channel proteins most closely related to the bacterial glycerol facilitators. The protein is localized in the plasma membrane. The physiological role of Fps1p appears to be glycerol export rather than uptake. Fps1 delta mutants are sensitive to hypo-osmotic shock, demonstrating that osmolyte export is required for recovery from a sudden drop in external osmolarity. In wild-type cells, the glycerol transport rate is decreased by hyperosmotic shock and increased by hypo-osmotic shock on a subminute time scale. This regulation seems to be independent of the known yeast osmosensing HOG and PKC signalling pathways. Mutants lacking the unique hydrophilic N-terminal domain of Fps1p, or certain parts thereof, fail to reduce the glycerol transport rate after a hyperosmotic shock. Yeast cells carrying these constructs constitutively release glycerol and show a dominant hyperosmosensitivity, but compensate for glycerol loss after prolonged incubation by glycerol overproduction. Fps1p may be an example of a more widespread class of regulators of osmoadaptation, which control the cellular content and release of compatible solutes.
Water-Electrolyte Balance
Gene Deletion
pharmacology
genetics
Osmolar Concentration
Fungal
Signal Transduction
Saccharomyces cerevisiae Proteins
genetics
Fungal Proteins
Membrane Proteins
metabolism
Gene Expression Regulation
Glycerol
Hypertonic Solutions
growth & development
Saccharomyces cerevisiae
metabolism
metabolism
metabolism
Biological Transport
genetics
Author
Markus J. Tamás
University of Gothenburg
K Luyten
F C Sutherland
A Hernandez
J Albertyn
H Valadi
University of Gothenburg
H Li
B A Prior
S G Kilian
J Ramos
L Gustafsson
University of Gothenburg
J M Thevelein
Stefan Hohmann
University of Gothenburg
Molecular Microbiology
0950-382X (ISSN) 1365-2958 (eISSN)
Vol. 31 4 1087-104Subject Categories
Biochemistry and Molecular Biology
PubMed
10096077