Figure 2

B. subtilis sporulation network model architecture. This cartoon model represents the sporulation initiation in B. subtilis. IPTG relieves LacI repression on the gene coding for KinA. KinA dimer auto-phosphorylation is regulated by an unknown sporulation signal (SS), which is generated by the unfavourable environmental conditions (lack of nutrients or high density population). Activated KinA transfers phosphor groups to Spo0F, which then leads to Spo0A phosphorylation via the phosphotransferase Spo0B. Dephosphorylation of Spo0F and Spo0A is modelled by abstracting the phosphatase species Spo0E and RapA. Spo0A~P acts as a transcription factor, and activates gene transcription by binding to the spoll promoters. mRNAs are translated into important sporulation initiation proteins, AA, AB, AC, IIE, GA and GB.