Accumulation and release of the osmolyte glycerol is dependent of the putative MIP channel Spac977.17p in Schizosaccharromyces pombe

Gerald Kayingo, Vladimir Sirotkin, Stefan Hofmann, Bernard A. Prior

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Schizosaccharomyces pombe accumulates glycerol as an osmotic regulatory solute in response to hyper-osmotic conditions. Upon a decrease in the external osmolarity, the intracellular glycerol levels should be adjusted in order to attain osmotic homeostasis. In this study, the patterns and kinetics of glycerol export from S. pombe were investigated. Upon a decrease in external osmolarity, glycerol was rapidly exported from cells to the external medium. The amount of glycerol released from the cells was proportional to the degree of change in the external osmolarity. The export process was well controlled and was not affected by reduced temperature. This points to S. pombe controlling glycerol export using specialized facilitating proteins as has been found in Saccharomyces cerevisiae where a MIP family channel protein Fps1p is involved. Analysis of the S. pombe databases revealed a putative transport protein (Spac977.17p) with homology to glycerol channel proteins of the MIP family. However, expression of the gene into the S. cerevisiae strain lacking a glycerol channel protein (fps1Δ mutant), did not complement the defect in glycerol export during hypo-osmotic stress. Deletion of spac977.17, did not affect glycerol accumulation or release in S. pombe. The patterns and kinetics of glycerol release in the mutant were similar to those of the wild type strains suggesting that the export process is independent of Spac977.17p, the only putative MIP family glycerol channel homologue in S. pombe. While the process of glycerol export in response to hypo-osmotic stress is similar to budding yeast, the underlying molecular mechanism in S. pombe appears distinct from that described in S. cerevisiae. Further studies are needed to elucidate the physiological role of the Spac977.17p channel.

Original languageEnglish (US)
Pages (from-to)85-92
Number of pages8
JournalAntonie van Leeuwenhoek, International Journal of General and Molecular Microbiology
Issue number2
StatePublished - Feb 2004
Externally publishedYes


  • Glycerol export
  • Hypo-osmotic stress
  • MIP channel
  • S. pombe

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology


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