Molecular characterization of autophagosomes from the yeast Saccharomyces cerevisiae

• Applicant: Professor Dr. Michael Thumm
• Subject Area: Microbiology, Virology and Immunology
• Term: from 2002 to 2006
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5374767

Legionella and Brucella spp. are severe pathogens causing Legionnaires disease and brucelliosis. After entering host cells by phagocytosis, they exploit the autophagic machinery to be taken up in an autophagosome-like organelle. To escape lysosomal breakdown the bacteria then prevent its fusion with lysosomes and finally trigger its maturation to a replication organelle. The bacteria-containing autophagosome plays a central role in virulence. Thus molecular characterization of this organelle is a way to identify novel targets for the treatment of these infections. We will isolate autophagosomes from already identified Saccharomyces cerevisiae mutants, which accumulate autophagosomes, and then identify autophagosome specific membrane proteins and lipids. The homologes of the yeast autophagosomal markers then can be used to characterize the bacteria-containing organelles in mammalian cells. Proteins of the autophagosomal outer membrane probably are involved in fusion of autophagosomes with lysosomes. Since inhibition of this fusion is crucial for virulence, also characterization of these components is planned. Yeast mutants defective in autophagosome biogenesis should accumulate autophagosomal components at a novel preautophagosomal compartment. Analysis of the preautophagosome in these mutants, thus is also part of the planned work to identify autophagosomal constituents.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1131: Life Inside Cells