Microbial Morphogenesis and Growth Laboratory, Institut Pasteur, Paris, France
Andrey Aristov
Microbial Morphogenesis and Growth Laboratory, Institut Pasteur, Paris, France
Laura Alvarez
Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, Umeå, Sweden
Gizem Özbaykal
Microbial Morphogenesis and Growth Laboratory, Institut Pasteur, Paris, France; Université Paris Diderot, Sorbonne-Paris-Cité, Paris, France
Thibault Chaze
Proteomics Platform, Institut Pasteur, Paris, France
Enno Rainer Oldewurtel
Microbial Morphogenesis and Growth Laboratory, Institut Pasteur, Paris, France
Mariette Matondo
Proteomics Platform, Institut Pasteur, Paris, France
Felipe Cava
Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, Umeå, Sweden
David Bikard
Synthetic Biology Laboratory, Institut Pasteur, Paris, France
Cell shape and cell-envelope integrity of bacteria are determined by the peptidoglycan cell wall. In rod-shaped Escherichia coli, two conserved sets of machinery are essential for cell-wall insertion in the cylindrical part of the cell: the Rod complex and the class-A penicillin-binding proteins (aPBPs). While the Rod complex governs rod-like cell shape, aPBP function is less well understood. aPBPs were previously hypothesized to either work in concert with the Rod complex or to independently repair cell-wall defects. First, we demonstrate through modulation of enzyme levels that aPBPs do not contribute to rod-like cell shape but are required for mechanical stability, supporting their independent activity. By combining measurements of cell-wall stiffness, cell-wall insertion, and PBP1b motion at the single-molecule level, we then present evidence that PBP1b, the major aPBP, contributes to cell-wall integrity by repairing cell wall defects.
