Bacillus subtilis MreB Orthologs Self-Organize into Filamentous Structures underneath the Cell Membrane in a Heterologous Cell System.
01.11.2011
Dempwolff F, Reimold C, Reth M, Graumann PL
PLoS One. 2011;6(11):e27035.
Actin-like bacterial cytoskeletal element MreB has been shown to be essential for the maintenance of rod cell shape in many bacteria. MreB forms rapidly remodelling helical filaments underneath the cell membrane in Bacillus subtilis and in other bacterial cells, and co-localizes with its two paralogs, Mbl and MreBH. To study the function of these proteins we used a synthetic biology approach namely the rebuilding of these bacterial protein complexes in the evolutionary distant environment of a Drosophila S2 Schneider cell. In this system MreB proteins form ATP-regulated filaments underneath the S2 cell membrane. An extended expression of MreB resulted in the formation of membrane protrusions, showing that like actin, MreB can exert force against the cell membrane. When co-expressed, MreB, Mbl and MreBH built up mixed filaments underneath the cell membrane. Our study shows, that MreB paralogs form a self-organizing and dynamic filamentous scaffold underneath the membrane that is able to recruit other proteins to the cell surface.
A YFP-MreB D158A mutant protein with reduced ATPase activity forms extrusions (green) on the surface
of S2 cells. Note that the cell membrane (red) is below the focal plane and appears as a haze.