Bacterial Cell Division

Abstract

Bacterial cell division or cytokinesis is the process in which a bacterial cell is split into two progeny cells, each with a copy of the chromosome. In most bacteria this process in initiated by the formation of the Z ring, a dynamic structure consisting of polymers of FtsZ , a tublin family member. The Z ring recruits additional division proteins to form the septal ring, also called the divisome, which leads to the synthesis of the septum separating the progeny cells. Spatial regulation of Z‐ring formation occurs primarily through negative regulators of FtsZ assembly that are positioned within the cell. The Z ring forms where the concentration of these negative regulators is at a minimum. A variety of regulators and mechanisms for positioning them have been identified in different bacteria. Among the mechanisms are the binding of a regulator to the segregating chromosome or the divisome itself and a self‐organizing system. Key concepts: Division depends on a cytoskeletal element (Z ring) that functions as a scaffold to recruit all the division proteins. Spatial regulation of Z ring placement involves positioning inhibitors of FtsZ in the cell to prevent FtsZ polymers from coalescing into the ring. Dynamic self‐organization – the ability of proteins to form dynamic structures and patterns fuelled by nucleotide hydrolysis; the Min system produces an oscillatory pattern and FtsZ filaments have the ability to form rings when attached to a lipid bilayer that has a cylindrical shape.

Quantitative analysis of time-series fluorescence microscopy using a spot tracking method: application to Min protein dynamics

“…In Escherichia coli and other rod-shaped bacteria, cell division depends on the precise placement of a division septum in the middle of the cell, a process initiated by the assembly of an equatorial ring (Z-ring) of the tubulin-like FtsZ GTPase on the cytoplasmic membrane (Lutkenhaus & Addinall 1997;Rothfield et al 1999). The Z-ring assembly is spatially restricted to midcell by nucleoid occlusion (Woldringh et al 1991;Yu & Margolin 1999) and by the dynamics of the Min system (de Boer et al 1989;Rothfield et al 2001).…”

A DNA damage checkpoint in Caulobacter crescentus inhibits cell division through a direct interaction with FtsW

“…In E. coli, these components assemble in an ordered fashion. The first protein to assemble is FtsZ, which polymerizes at mid-cell into a ring-like structure that is tethered to the cytoplasmic surface of the inner membrane (Lutkenhaus and Addinall 1997;Adams and Errington 2009). In addition to its direct role in constriction, the Z-ring also nucleates assembly of the rest of the divisome, which ultimately coordinates constriction and membrane invagination with construction of a septum, a process that requires localized peptidoglycan synthesis .…”

Mouse models for assessing the cross-protective efficacy of oral non-typhoidal Salmonella vaccine candidates harbouring in-frame deletions of the ATP-dependent protease lon and other genes

“…Thus, we constructed inframe markerless deletion mutants that included lon deletion in both S. Typhimurium and S. Enteritidis. Bacterial cell division occurs through the formation of an FtsZ ring (Z ring) at the site of division, which is inhibited by SulA, a member of the SOS regulon and a specific target of the Lon protease, by binding to a polymerizationcompetent form of FtsZ in a 1 : 1 ratio (Lutkenhaus & Addinall, 1997). The inhibition of FtsZ-mediated cell division by the expression of SulA induces a filamentous form of S. Typhimurium that is unable to invade epithelial cells (Humphrey et al, 2011).…”