Schematic of the reactions of the stressosome. The reactions take place on the icosahedral stressosome structure, except for RsbT*, which is cytoplasmic RsbT. RsbT* initiates the general stress response by binding to RsbU and the subsequent release of σB through a partner switching mechanism. ‘Stim’ represents stimulation of the stressosome by a stressor. We tested three models of interactions between RsbR and RsbT: no interactions; RsbR as an activator of RsbT (A); RsbR-P as an activator of RsbT (B). The reaction parameters correspond to those of Table 1. Arrows represent reactions and lines with circles denote activation.