Regensburg 2016 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 60: Pattern Formation (Joint Session with DY)
BP 60.9: Vortrag
Donnerstag, 10. März 2016, 12:00–12:15, H46
A Protein Flux-based Mechanism for Midcell Sensing in Bacteria — •Silke Bergeler1, Dominik Schumacher2, Lotte Søgaard-Andersen2, and Erwin Frey1 — 1ASC for Theoretical Physics, Ludwig-Maximilians-Universität, München, Germany — 2Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
Precise positioning of the cell division site is crucial for the correct separation of the genetic material into the two daughter cells. In myxobacteria a cluster of Pom proteins (PomX, PomY, PomZ) is formed on the chromosome that performs a biased random walk to midcell and positively regulates cell division. To investigate how the Pom cluster, consisting of PomX and PomY, moves to midcell, we introduce a mathematical model in which PomZ dimers can attach to, diffuse on the nucleoid and can hydrolyze ATP and subsequently detach from the nucleoid primarily at the cluster. It is known that this type of particle dynamics leads to different fluxes of PomZ into the cluster from both sides along the long cell axis, if the cluster is at an off-center position, but it is not known how the force to move the cluster is generated. We model the PomZ dimers as springs, based on the observation that the bacterial chromosome and several proteins have elastic properties. As springs the PomZ dimers can exert a force on the PomXY cluster. Our model explains mid-plane localization of the Pom cluster. It predicts a decrease in the efficiency to find midcell for a large number of PomZ dimers in the cell and small ATP-hydrolysis rates of the ATPase PomZ, which is in agreement with our experimental findings. In summary, our study provides new mechanistic insights into intracellular positioning.