Berlin 2018 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 18: Focus Session: Physics of Microbial Systems - organized by Tobias Bollenbach and Benedikt Sabass
BP 18.7: Vortrag
Mittwoch, 14. März 2018, 11:30–11:45, H 2013
Sensitivity, dynamics and robustness of extracellular PhrA-signaling in Bacillus subtilis — Heiko Babel1,2, •Pablo Naranjo1,2, Stephanie Trauth1,2, Victor Sourjik1, and Ilka Bischofs1,2 — 1MPI for Terrestrial Microbiology, Marburg, Germany — 2BioQuant, University of Heidelberg, Germany
Communication is an essential for the self-organization of bacterial populations. The underlying molecular networks that serve this task are surprisingly diverse. In order to understand how the different architectures affect signaling performance, new biophysical tools are required that allow us to quantitatively characterize the function of individual network components and signaling processes in the bacterial cell. A common form of signaling in Gram-positive bacteria is by means of signaling peptides that are produced by an active export-import circuit and are sensed intracellularly. Here, we developed the first FRET-reporter to quantitatively study PhrA-signaling in Bacillus subtilis. Using acceptor photo-bleaching experiments we studied the intra- and extracellular dynamics in response to peptide stimulation and developed a mathematical model that fits the data well. We find that the PhrA signaling circuit, although relying on a low affinity receptor, exhibits exquisite sensitivity to low extracellular signal levels. Our data furthermore suggests that oligopermeases - a component that is shared by all RNPP-signaling circuits in Gram-positive bacteria - play a central role in governing the sensitivity and dynamics of extracellular peptide signaling, while potentially also limiting the robustness of signaling in the presence of other peptides.