Piet A.J. de Boer
Bacterial cytokinesis is mediated by the septal ring (SR, divisome), a cytoskeletal-like organelle that forms at the future site of cell fission and then drives the coordinate invagination of the inner membrane, peptidoglycan, and outer membrane layers during the process. In E.coli, the SR consists of at least ten essential division proteins and over twenty other proteins with redundant and/or non-essential activities in the division process. SR development involves assembly of an early FtsZ-ring (Z-ring) intermediate, recruitment of additional proteins to form a fission-competent SR, and further modifications after the onset of the fission process. The long-term goals of his lab's work is to understand at a molecular level: i) The composition and architecture of the SR, ii) How the SR assembles from its different components, iii) How the proper site for its assembly is determined, iv) How the SR drives cell fission, and v) How SR function is coordinated with other cell cycle events, such as nucleoid replication/segregation and cell elongation.
The peptidoglycan (PG, murein) sacculus is a major determinant of bacterial cell shape. In turn, shape of the sacculus is determined by trans-envelope cell elongation machineries (CEM's) that include PG synthases and hydrolases as well as a set of proteins, including MreB-actin, that somehow dictate the cellular distribution and activities of the PG enzymes such that cells grow as rods rather than spheres. They wish to understand the composition and architecture of CEM's and especially how the organization of PG enzymes in CEM's restricts cell/sacculus growth to a single axis during cell elongation.