%0 Journal Article
%T Simulations of stressosome activation emphasize allosteric interactions between RsbR and RsbT
%A Ulf W Liebal
%A Thomas Millat
%A Jon Marles-Wright
%A Richard J Lewis
%A Olaf Wolkenhauer
%J BMC Systems Biology
%D 2013
%I BioMed Central
%R 10.1186/1752-0509-7-3
%X 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.The stressosome signalling complex of Bacillus subtilis is activated in response to diverse environmental stresses, including ethanol, temperature, UV light, and osmolarity, and initiates a protein partner switching cascade that leads to the release of the alternative transcription factor ¦ÒB[1-3]. The complex is the most upstream component so far characterised of the environmental arm of the general stress response in B. subtilis[1,4]. Its activation results in the upregulation of nearly 200 genes, including proteins which provide protective adaption to environmental change [5-8].The stressosome has a supra-molecular structure of a truncated icosahedron [9,10] and consists of the presumed sensor protein, RsbR, and the scaffold protein, RsbS [11-13]. The cryo-EM structure of the stressosome revealed its molecular organisation with 40 copies of RsbR associated with 20 RsbS molecules (arranged in homodimers) (Figure 1A) [10]. In the ground state, 20 RsbT molecules are bound by 20 copies of RsbS [10]; RsbT dissociates from the stressosome following activation by environmental stress
%K Bacillus subtilis
%K Stressosome
%K Signalling
%K Cellular automaton
%K Stress response
%U http://www.biomedcentral.com/1752-0509/7/3