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Revisiting the Hog Pathway of C. glabrata
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Poster number: 13
Zeljkica Jandric, Wolfgang Reiter, Gustav Ammerer, Christoph Schüller
Max F. Perutz Laboratories, Department of Biochemistry University of Vienna, Dr.Bohr-
Gasse 9/5, A-1030 Vienna, Austria
Signal transduction networks mediated by mitogen – activated protein kinases
(MAPK) play essential roles in eukaryotic cells. Yeast cells have developed
osmoadaptation pathways to cope with osmotic changes in the microenvironment.
In Saccharomyces cerevisiae five MAPK pathways are well characterized. One of
these, especially associated with stress response, is the High Osmolarity Glycerol
(HOG) pathway . Stress induced phosphorylation triggers the activation of the key
MAPK, Hog1. After being phosphorylated by the upstream MAPKK Pbs2, Hog1
enters the cell nucleus and modulates the transcription of its target genes.
Orthologues of the all HOG pathway compounds found in Saccharomyces
cerevisiae have been identified in fungi and animals.
The human fungal pathogen Candida glabrata is closely related to Saccharomyces
cerevisiae. It is a common commensal but in immunocompromised cancer and
transplant patients or elder persons it can turn into an opportunistic pathogen.
Depending on the host environment, Candida glabrata has to adapt to
environmental changes during invasion and adaptation steps. We investigated the
role of Hog1 in Candida glabrata. Several stress sources were used to identify HOGspecific
phenotypes and to analyze the role of Hog1 in Candida glabrata. As
expected, the deletion of Hog1 caused osmostress hypersensitivity. Physiological
stress conditions, such as nutrients starvation, were simulated by infection of
macrophages with Candida glabrata and determination of the number of surviving
Candida cells. Cghog1∆ cells showed a much higher sensitivity to macrophages
compared to wild type cells. Further investigations focus on stress induced gene
transcription in Cghog1∆ cells and comparison of the transcription pattern to cells
without Hog1 deletion.