elzbieta.petelenz@gmm.gu.se

Supervisor: STEFAN HOHMANN

hohmann@gmm.gu.se

Yeast, especially Saccharomyces cerevisiae, is a commonly used model organism for many fields of research – genetics, physiology, biochemistry, but also structural biology, bioinformatics and many others. The main focus of this project is the functioning of the osmoregulatory HOG (High Osmolarity Glycerol) pathway in the yeast Saccharomyces cerevisiae. It is an example of a MAP kinase cascade.

Yeast strains suitable for studying and quantification of the osmotic stress response in single yeast cells are being developed. The strains are supposed to express suitable GFP (Green Fluorescent Protein) fusion constructs, designed to monitor protein localisation within the cell and possibly to perform FRET (Fluorescence Resonance Energy Transfer). For this purpose fluorescence microscopy, as well as optical manipulation tools combined with micro-fluid systems, and prospectively flow cytometry, is being used. Another aspect is examining cell volume changes, by using optical tweezers and micro-fluidic channels (in collaboration with Dag Hanstorp’s group, Department of Physics, Göteborg University). The collected data will serve to refine existing mathematical models of the HOG pathway.

The HOG pathway is divided into two branches: Sln1 and Sho1. In this project the contributions of each branch and mechanisms of their regulation are being explored, with emphasis on feedback regulation. In collaboration with prof. Edda Klipp and her group, the obtained data will be used to test different model scenarios, with respect to individual contributions of the two branches of the HOG pathway to the stress signal transduction.