VAAM-Jahrestagung 2011 Karlsruhe, 3.–6. April 2011

possibility that the transcription elongation machinery is specificallymodified during asexual development.[1] Schier et al (2002): FEBS Lett. 523: 143-6.[2] Bathe et al (2010): Eukaryot Cell. 9: 1901-12.CBP020Will not be presented!CBP021Subcellular localization of Sortase A in staphylococciW. Yu*, D.D. Demircioglu, S. Perconti, F. GötzDepartment of Microbial Genetics, University of Tübingen, Tübingen,GermanyCell wall anchored surface proteins play important roles in the pathogenicityof Staphylococcus aureus. While the biochemical process of anchoringsurface proteins by Sortase A (SrtA) in S. aureus has been studied in detail,the spatial and temporal knowledge is largely missing. By anchoring redfluorescent protein Mcherry to the peptidoglycan (Mch-cw) as a modelsystem for localization studies, we found that Mch-cw strongly accumulatedat crosswall (septum) when S. aureus was treated with cell wall biosynthesisantibiotics, such as moenomycin or penicillin. The accumulation wasabolished in S. aureus ΔsrtA. Second, in a S. aureus ΔtagO mutant that lackswall teichoic acid, both the presentation of Mch-cw to cell surface and celldivision are greatly delayed. A Sortase-GFP fusion showed that Sortase Awas predominantly localized at the septum with a few foci localized at thesidewall in S. aureus wild type. However, these data were provided byplasmid-based fusion proteins that need to be verified by immunofluorescentmicroscopy study. Further, we seek to understand the localization of SortaseA in the presence of cell wall biosynthesis antibiotics as well as in S. aureusΔtagO. Our data suggested that anchoring of surface proteins to cell wall isclosely connected with cell division and occurs mainly at the crosswall.CBP022Bactofilins: a new class of cytoskeletal proteinsJ. Kühn* 1,2 , A. Briegel 3 , E. Mörschel 2 , J. Kahnt 4 , G.J. Jensen 3 ,M. Thanbichler 1,21 Research Group Prokaryotic Cell Biology, Max Planck Institute forTerrestrial Microbiology, Marburg, Germany2 Department of Biology, Philipps-University, Marburg, Germany3 Division of Biology and Howard Hughes Medical Institute, CaliforniaInstitute of Technology, Pasadena, USA4 Department of Ecophysiology, Max Planck Institute for TerrestrialMicrobiology, Marburg, GermanyThe cytoskeleton plays a key role in the temporal and spatial organization ofboth prokaryotic and eukaryotic cells. Moreover, the principal set-up ofthese scaffolding proteins shows striking similarities in both branches,including nucleotide cofactor-dependent and -independent components.Here, we report the identification of a new class of polymer-formingproteins, termed bactofilins, that are widely conserved among bacteria. InCaulobacter crescentus, two bactofilin paralogues cooperate to form a sheetlikestructure lining the cytoplasmic membrane in proximity of the stalkedcell pole. These assemblies mediate polar localization of a peptidoglycansynthase involved in stalk morphogenesis, thus complementing the functionof the actin-like cytoskeleton and the cell division machinery in theregulation of cell wall biogenesis. In other bacteria, bactofilins can establishrod-shaped filaments or associate with the cell division apparatus, indicatingconsiderable structural and functional flexibility. Bactofilins polymerizespontaneously in the absence of additional cofactors in vitro, forming stableribbon- or rod-like filament bundles. Our results suggest that these structureshave evolved as an alternative to intermediate filaments, serving as versatilemolecular scaffolds in a variety of cellular pathways.[1] Kühn, J. et al (2010): Bactofilins, a ubiquitous class of cytoskeletal proteins mediating polarlocalization of a cell wall synthase in Caulobacter crescentus. EMBO J. 29:327-339.CBP023Helicobacter pylori posseses four coiled coil rich proteins(Ccrp) that affect cell shape and form extendedfilamentous structuresM. Specht* 1 , S. Schätzle 2 , P.L. Graumann 1 , B. Waidner 21 Department of Microbiology, Albert-Ludwigs-University, Freiburg,Germany2 Institute for Medical Microbiology and Hygiene, University MedicalCenter, Freiburg, GermanyPathogenicity of the human pathogen Helicobacter pylori relies upon itscapacity to adapt to a hostile environment and to escape the host response.Therefore, the shape, motility, and pH homeostasis of these bacteria arespecifically adapted to the gastric mucus. Recently, we have shown that thehelical shape of H. pylori depends on two coiled coil rich proteins (Ccrp),which form extended filamentous structures and are required for themaintenance of cell morphology to different extents. Next to the genescoding for Ccrp59 and Ccrp1143 proteins, we have found that H. pyloripossesses two additional genes potentially encoding Ccrp proteins. Indeed,Ccrp58 and Ccrp1142 also have an impact on cell morphology indicating acomplex system for maintenance of cell shape of this human pathogen.Likewise both new identified proteins build up filamentous structures invitro. Interestingly, although all Ccrp mutants posses a normal flagellaformation, the strains displayed a reduced motility. All four Ccrps havedifferent multimerization and filamentation properties suggesting a systemof individual filaments. Thus, H. pylori cells express four Ccrp-proteins thatdifferentially affect cell morphology and have somewhat differentbiochemical properties, suggesting that helical cell shape is establishedthrough a complex network of individual cytoskeletal components.CBP024Localization pattern of a Gram positive conjugationmachineryT. Bauer 1 , T. Rösch* 1,2 , M. Itaya 3 , P.L. Graumann 11 Faculty of Biology II/Microbiology, Albert-Ludwigs University, Freiburg,Germany2 Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University, Freiburg, Germany3 Institute for Advanced Biosciences, Laboratory of Genome DesigningBiology, Tsuruoka, JapanConjugation is an efficient way for the transfer of genetic informationbetween bacteria, even between highly diverged species, and a major causefor the spreading of resistance genes. We have investigated the subcellularlocalization of several conserved conjugation proteins encoded on plasmidpLS20 found in Bacillus subtilis. We show that VirB1, VirB4, VirB11 andVirD4 homologs assemble at a single cell pole, but also at other sites alongthe cell membrane, in cells during lag phase of growth. SSB-like SsbCprotein also localizes to the cell pole, but when overproduced lowersconjugation efficiency, indicating that SsbC is also part of the conjugationmachinery, but must be present in moderate amounts. BiFC analyses showthat VirB4 and VirD4 interact at the cell pole and, less frequently, at othersites along the membrane, suggesting that this is a preferred site for theassembly of an active conjugation apparatus, but not the sole site. TIRFmicroscopy shows that pLS20 is largely membrane-associated, and isfrequently found at the cell pole, indicating that transfer takes place at thepole. All analysed conjugative proteins localize to the pole or the membranein stationary phase cells and in cells that have been resuspended in freshmedium, but no longer in cells that enter exponential growth, although atleast VirB4 is synthesized at equal level. These data reveal an unusualassembly/disassembly timing for the pLS20 conjugation machinery andsuggest that specific localization of conjugation proteins in non-growingcells and delocalization during growth are the reason why pLS20conjugation only occurs during early exponential (lag) phase.CBP025Dynamic range in bacterial chemotaxisA. Krembel*, S. Neumann, V. SourjikCenter for Molecular Biology, DKFZ-ZMBH Alliance, University ofHeidelberg, Heidelberg, GermanyMost motile bacteria are able to follow chemical gradients in itsenvironment through a mechanism called chemotaxis. Bacterial chemotaxisspektrum | Tagungsband 2011