Identifikation und funktionelle Charakterisierung von Effektorproteinen des Typ III-Sekretionssystems von Chlamydia pneumoniae

• Applicant: Professor Dr. Uwe Groß
• Subject Area: Parasitology and Biology of Tropical Infectious Disease Pathogens
• Term: from 2002 to 2007
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5373615

Like many gram-negative bacteria, the obligate intracellular pathogen Chlamydia pneumoniae expresses a type III secretion system (TTSS). Several genes coding for proteins of the TTSS have been investigated by us both, on RNA and on protein level. It was shown that all of the following, YscN (ATPase), LcrE (supposed to be the "lid" of the TTSS), LcrH and ycE (both believed to be chaperons) are expressed late during intracellular development (24-48h p.i.). Additionally, we could demonstrate that the genes coding for potential effector proteins (incA, incB and incC) are transcribed relatively early during the intracellular development and that the respective proteins are localized to the membranes of the inclusion bodies. Very little is known about proteins that are secreted into the host cell via the TTSS. In this project, putative genes that are considered to be involved in the TTSS-associated communication between C. pneumoniae and its host cell will therefore be identified and characterized. Furthermore, using the yeast two-hybrid system, host cell proteins which might interact with these bacterial effector proteins will be identified. For this purpose, we will not only use HEp-2 cells but also Sacharomyces cerevisiae as target cells because in contrast to the former, yeast cells are not immortalized and a high degree of overlap exists betwen signal pathways of S. cerevisiae and other eukaryotic cells. Finally, C. pneumoniae proteins that have been shown to interact with cellular proteins will be expressed in HEp-2 cells or in S. cerevisiae in order to precisely analyse the resulting modulation of target-cell gene expression and to investigate its underlying mechanism(s).

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