Division site selection in Bacillus subtilis: Structure and function of the novel component MinJ

• Applicant: Professor Dr. Marc Bramkamp
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2010 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 182460133

In rod-shaped bacteria the site of septation is usually found with exquisite precision. In Escherichia coli and Bacillus subtilis two inhibitory systems have been connected with division site selection, the nucleoid occlusion system and the Min system. In B. subtilis the Min system was supposed to consist out of three proteins, DivIVA, MinD, and MinC. MinCD is the actual inhibitory complex of cytokinesis, while DivIVA imposes topological control on MinCD. We and others recently identified a new member of the B. subtilis Min system, MinJ. It came as a surprise to learn that MinJ is an actual adapter that bridges DivIVA and MinD. We have found that the role of the MinCDJ system controls cytokinesis not only at the level of FtsZ inhibition, but also at the level of membrane integral division proteins. In this proposal I wish to address five major points that will help to understand the function of the B. subtilis Min system in more detail. i) We will map the interactions sites that MinJ has with DivIVA, MinD, and with the membrane integral division proteins. ii) We want to obtain structural information of MinJ. iii) We will investigate what the exact effect of MinCD on the membrane proteins of the divisome is iv) We will employ newly developed screening techniques to answer the question whether there are hitherto unidentified partners in this process. v) We wish to find out how the inhibitory function of MinCD is overcome during sporulation of B. subtilis, although the Min system is still active under these conditions.

• DFG Programme: Research Grants