Mechanisms of FtsZ-based cell division

Most bacteria and archaea divide using a cytokinetic structure, the Z-ring, which contains the tubulin-like FtsZ protein. The Z-ring recruits the divisome, a trans-membrane protein complex that synthesises peptidoglycan, which leads to cell constriction and division through inwards growth of the cell wall. With this proposal we aim to unravel the molecular events that drive cell division. To understand how the Z-ring organises division, we will reveal its structure using electron cryotomography in cells, for which we have developed EM technology to image complete division planes. We will uncover how cell wall is grown for division through a comprehensive structure and function analysis of divisomes, including how they polymerise lipid II into peptidoglycan. How Z-ring attachment activates the divisome will be analysed in vitro and in vivo. Usefulness and completeness of the mechanisms revealed will be tested with in vitro liposome experiments recapitulating peptidoglycan polymerisation and Z-rings, and enabling cell division reconstitution, a goal of synthetic biology. Since some FtsZ-containing archaea and bacteria have no cell wall, we will investigate how they divide without it. Finally, since cell elongation by the elongasome also involves peptidoglycan synthesis, we will uncover why the divisome thickens cell wall, while the elongasome widens it.