Bacterial Cytoskeletal Elements Establishment of morphogenesis in bacteria ? ? Cytoskeletal elements The bacterial cytoskeleton Eukaryotes tubulin actin IFs Bacteria FtsZ MreB Ccrp (Crescentin) 3D structures of cytoskeletal elements Phylogeny of FtsZ Tubulin ortholog FtsZ forms a ring-like structure in the cell centre Immuno-fluorescence of FtsZ (red) and DNA (green) in Bacillus subtilis E. coli: FtsZ-GFP Tubulin forms hollow tubules, while FtsZ forms single strand polymers Assembly of the divisome Cell division in Bacillus subtilis Actin Treadmilling Plasmid segregation via a double protein filament K. Gerdes, J. Pogliano Bipolar movement through search and capturing of a second plasmid ParM-Alexa 488, ParR-Alexa red D. Mullins Structures of actin-like proteins F-actin and MreB filaments MreB MreB ParM ParM MreB J. Löwe Depletion of MreB (or MreC) leads to the formation of round cells and is lethal 2 4 6 doubling times membrane-stain The depletion of MreB leads to a loss in rod- shaped cell morphology GFP-MreB: dynamc helical filaments? GFP-MreB 2D arrangement of MreB filaments 3D arrangement of MreB filaments Filament dynamics at 100 nm resolution: TIRF-SIM YFP-MreB N-SIM A. Rohrbach Model for the generation of rod shape Intermediate-Filament proteins Crescentin affects cell curvature in Caulobacter crescentus C. Jacobs-Wagner, Yale Crescentin localizes to the short axis of the cell Crescentin forms left handed helices Crescentin-YFP Deletion of IF encoding genes leads to loss of cell shape in Helicobacter pylori Ccrps (coiled coil-rich proteins) form long bundles of filaments Cell curvature through mechanical bending of cells via a rigid protein filament Positioning of magnetosomes through an actin-like protein (MamK) Spiroplasma melliferum Bacterial cytoskeletal elements Model for the function of MreB Motility of Spiroplasma Filament formation in a mammalian cell system YFP-MreB CFP-Mbl mCherry-MreBH .