Simulations of stressosome activation emphasize allosteric interactions between RsbR and RsbT


The stressosome is a bacterial signalling complex that responds to environmental changes by initiating a protein partner switching cascade, which leads to the release of the alternative sigma factor, sigmaB. Stress perception increases the phosphorylation of the stressosome sensor protein, RsbR, and the scaffold protein, RsbS, by the protein kinase RsbT. Subsequent dissociation of RsbT from the stressosome activates the sigmaB cascade. However, the sequence of physical events that occur in the stressosome during signal transduction is insufficiently understood.

Here, we use computational modelling to correlate the structure of the stressosome with the efficiency of the phosphorylation reactions that occur upon activation by stress. In our model, the phosphorylation of any stressosome protein is dependent upon its nearest neighbours and their phosphorylation status. We compare different hypotheses about stressosome activation and find that only the model representing the allosteric activation of the kinase RsbT, by phosphorylated RsbR, qualitatively reproduces the experimental data.

Our simulations and the associated analysis of published data support the following hypotheses: (i) a simple Boolean model is capable of reproducing stressosome dynamics, (ii) different stressors induce identical stressosome activation patterns, and we also confirm that (i) phosphorylated RsbR activates RsbT, and (ii) the main purpose of RsbX is to dephosphorylate RsbS-P.


DOI: 10.1186/1752-0509-7-3

Projects: BaCell-SysMO

Journal: BMC Syst Biol


Date Published: 2013

Authors: Ulf Liebal, Thomas Millat, Jon Marles-Wright, Rick Lewis, Olaf Wolkenhauer

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Liebal, U. W., Millat, T., Marles-Wright, J., Lewis, R. J., & Wolkenhauer, O. (2013). Simulations of stressosome activation emphasize allosteric interactions between RsbR and RsbT. BMC Systems Biology, 7(1), 3.

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Created: 15th Jan 2013 at 14:19

Last updated: 15th Jan 2013 at 14:21

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