[SCAN] Peptidoglycan synthesis drives FtsZ treadmilling-independent step of cytokinesis

SCAN

Title: Peptidoglycan synthesis drives FtsZ treadmilling-independent step of cytokinesis

Speaker: Mariana Pinho

Affiliation: Bacterial Cell Biology Lab, ITQB NOVA

Abstract:

Peptidoglycan, the major component of the bacterial wall, protects cells from mechanical stress resulting from high intracellular turgor. Bacilli and ovococcal species possess two peptidoglycan synthesis machineries, specifically dedicated to either cell elongation or septation. In contrast, coccoid bacteria like Staphylococcus aureus possess only one peptidoglycan biosynthetic machinery, which is diverted from the cell periphery to the septum in preparation for division. The molecular cue that coordinates this transition has remained elusive. Here, we investigated the localisation of S. aureus peptidoglycan biosynthesis proteins and showed that the putative lipid II flippase is recruited to the septum by the the divisome, driving peptidoglycan incorporation to midcell. The flippase recruitment corresponds to a turning point in cytokinesis, which is slow and dependent on FtsZ treadmilling before MurJ arrival, but becomes faster and, surprisingly, independent of FtsZ treadmilling, when peptidoglycan synthesis activity is recruited to the septum, providing additional force for cell envelope constriction.