DipM, a new factor required for peptidoglycan remodelling during cell division in Caulobacter crescentus

• Published in: Molecular microbiology Vol. 77; no. 1; pp. 90 - 107
• Main Authors: Möll, Andrea, Schlimpert, Susan, Briegel, Ariane, Jensen, Grant J, Thanbichler, Martin
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01-07-2010; Blackwell Publishing Ltd; Blackwell; Wiley
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biological and medical sciences; Caulobacter crescentus; Caulobacter crescentus - cytology; Caulobacter crescentus - metabolism; Caulobacter crescentus - physiology; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Cell Division; Cytokines; Cytoplasm; DNA Mutational Analysis; DNA, Bacterial; Endopeptidases - genetics; Endopeptidases - metabolism; Enzymes; Fundamental and applied biological sciences. Psychology; Gram-negative bacteria; Membrane Proteins - metabolism; Microbiology; Miscellaneous; Molecular Sequence Data; Mutation; Peptidoglycan - metabolism; Periplasmic Proteins - genetics; Periplasmic Proteins - metabolism; Protein Binding; Protein Structure, Tertiary; Proteins; Sequence Analysis, DNA; Cell division; Caulobacter crescentus; Peptidoglycan; Bacteria; Caulobacterales; Caulobacteraceae; Life Sciences
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/j.1365-2958.2010.07224.x

In bacteria, cytokinesis is dependent on lytic enzymes that facilitate remodelling of the cell wall during constriction. In this work, we identify a thus far uncharacterized periplasmic protein, DipM, that is required for cell division and polarity in Caulobacter crescentus. DipM is composed of four peptidoglycan binding (LysM) domains and a C-terminal lysostaphin-like (LytM) peptidase domain. It binds to isolated murein sacculi in vitro, and is recruited to the site of constriction through interaction with the cell division protein FtsN. Mutational analyses showed that the LysM domains are necessary and sufficient for localization of DipM, while its peptidase domain is essential for function. Consistent with a role in cell wall hydrolysis, DipM was found to interact with purified murein sacculi in vitro and to induce cell lysis upon overproduction. Its inactivation causes severe defects in outer membrane invagination, resulting in a significant delay between cytoplasmic compartmentalization and final separation of the daughter cells. Overall, these findings indicate that DipM is a periplasmic component of the C. crescentus divisome that facilitates remodelling of the peptidoglycan layer and, thus, coordinated constriction of the cell envelope during the division process.