Compartmentalization of the periplasm at cell division sites in <i>Escherichia coli</i> as shown by fluorescence photobleaching experiments

Foley, Michael; Brass, J. M.; Birmingham, John J.; Cook, William R.; Garland, P. B.; Higgins, Christopher F.; Rothfield, Lawrence

doi:10.1111/j.1365-2958.1989.tb00114.x

Cited by 41 publications

(18 citation statements)

References 22 publications

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“…The reduced mobility of OM proteins may also result from the existence of a barrier between the polar and cylindrical parts of the cell instead of the direct murein-OM interaction as proposed above. Indeed, experimental data support the presence of a diffusion barrier for periplasmic elements at the edges of polar regions and developing septa (14,43). Nevertheless, the parallelism observed between areas of inert murein and restricted OM protein mobility seems too strict to be purely accidental.…”

Section: Discussionmentioning

confidence: 95%

Restricted Mobility of Cell Surface Proteins in the Polar Regions of Escherichia coli

2004

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The polar regions of the Escherichia coli murein sacculus are metabolically inert and stable in time. Because the sacculus and the outer membrane are tightly associated, we investigated whether polar inert murein could restrict the mobility of other cell envelope elements. Cells were covalently labeled with a fluorescent reagent, chased in dye-free medium, and observed by microscopy. Fluorescent material was more efficiently retained at the cell poles than at any other location. The boundary between high and low fluorescence intensity areas was rather sharp. Labeled material consisted mostly of cell envelope proteins, among them the free and mureinbound forms of Braun's lipoprotein. Our results indicate that the mobility of at least some cell envelope proteins is restrained at regions in correspondence with underlying areas of inert murein.The peptidoglycan (murein) sacculus of the bacterial cell wall plays a key role in bacterial morphogenesis (21,34,45,46,54). In gram-negative bacteria such as Escherichia coli, the sacculus occupies the periplasmic space between the cytoplasmic membrane (IM) and the outer membrane (OM) and interacts with both of them (24,34,35,44,45). Interaction with the OM is mediated by a number of proteins able to link murein to components of the OM. Among them, Braun's lipoprotein (Lpp) is remarkable as the only known protein that binds covalently to murein in E. coli (5, 6). Lpp is the most abundant protein in the cell envelope and coexists in free (60 to 70%) and murein-bound (30 to 40%) forms (4, 22). The attachment of Lpp to the OM presumably occurs through the insertion of the acyl chains into the inner phospholipid leaflet of the OM (4, 34, 57). Free Lpp molecules form trimers which may contribute to the strength of the murein-OM complex by additional noncovalent interactions (8,9,57). The sacculus and the OM also interact by means of noncovalently bound molecules such as the peptidoglycan-associated lipoprotein (PAL) and OmpA proteins. The binding between PAL and the sacculus is very strong and involves a murein-binding-specific sequence (26). PAL anchors to the OM primarily by the acylated N terminus, but direct protein-protein interactions with other OM proteins have been demonstrated (1, 26, 33). One of the major OM proteins is OmpA. It is an integral membrane protein with domains protruding from both the external and internal leaflets. On the outer side, it functions as a phage receptor, and on the internal side, it interacts directly with murein (18, 36). The interaction of OmpA with murein is strong enough to stabilize the cell envelope in the absence of Lpp (48,56). In addition to Lpp, PAL, and OmpA, a number of other proteins able to interact with the OM and the sacculus, such as OmpF and OmpC, may contribute to the total interaction as well (38).The turgor pressure of the cell forces a physical contact between the IM and the sacculus (23). However, no specific attaching elements have been demonstrated up to now. Interestingly the PAL-TOL complex might play such a role sinc...

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Section: Discussionmentioning

confidence: 95%

Restricted Mobility of Cell Surface Proteins in the Polar Regions of Escherichia coli

2004

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“…The periseptal and polar annuli divide the periplasm into three types of subcompartments: two polar and two midcell compartments and one compartment at the site of future division. By monitoring fluorescence recovery after photobleaching at the periseptal and polar annuli, Foley et al (38) found that the recovery of fluorescence was uniformly low over the zones of the periseptal and polar annuli. They proposed that these regions are biochemically sequestered from the remainder of the periplasmic space.…”

Section: Discussionmentioning

confidence: 99%

Translocation of Jellyfish Green Fluorescent Protein via the Tat System of Escherichia coli and Change of Its Periplasmic Localization in Response to Osmotic Up-shock

Santini¹,

Bernadac²,

Zhang³

et al. 2001

Journal of Biological Chemistry

179

121

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The bacterial twin arginine translocation (Tat) pathway is capable of exporting cofactor-containing enzymes into the periplasm. To assess the capacity of the Tat pathway to export heterologous proteins and to gain information about the property of the periplasm, we fused the twin arginine signal peptide of the trimethylamine N-oxide reductase to the jellyfish green fluorescent protein (GFP). Unlike the Sec pathway, the Tat system successfully exported correctly folded GFP into the periplasm of Escherichia coli. Interestingly, GFP appeared as a halo in most cells and occasionally showed a polar localization in wild type strains. When subjected to a mild osmotic up-shock, GFP relocalized very quickly at the two poles of the cells. The conversion from the halo structure to a periplasmic gathering at particular locations was also observed with spherical cells of the ⌬rodA-pbpA mutant or of the wild type strain treated with lysozyme. Therefore, the periplasm is not a uniform compartment and the polarization of GFP is unlikely to be caused by simple invagination of the cytoplasmic membrane at the poles. Moreover, the polar gathering of GFP is reversible; the reversion was accelerated by glucose and inhibited by azide and carbonyl cyanide m-chlorophenylhydrazone, indicating an active adaptation of the bacteria to the osmolarity in the medium. These results strongly suggest a relocalization of periplasmic substances in response to environmental changes. The polar area might be the preferential zone where bacteria sense the change in the environment.The periplasmic space lies between the inner and the outer membranes of Gram-negative bacteria. A number of processes that are vital to the growth and viability of the cell occur within this compartment. Proteins residing in the periplasmic space fulfill important functions in the detection, processing, and uptake of essential nutrient substances. These proteins are exported into the periplasm mainly via two pathways: the unfolded proteins via the Sec system (1) and the folded enzymes containing redox cofactor via the Tat 1 (or Mtt) pathway (2-4).The periplasm might not be a uniformly homogenous compartment; fine structures known as Bayer patches/bridges (5) and periseptal and polar annuli (6 -9) have been described. The existence of these structures under physiological conditions is a subject of contention (10,11). Nevertheless, these structures were proposed to provide sites required for the export of outer membrane components, murein synthesis, secretion of bacteriophages, and cell divisions (12).On the other hand, polar bacterial organization was observed with a variety of bacterial species and concerns a disparate array of cellular functions (13). In addition to the well known examples of polar organelles such as flagella, pili, and stalklike appendages at the bacterial surface, accumulating evidence shows that periplasmic, inner membranous, and cytoplasmic proteins may also exhibit polar localization under certain condition. These proteins participate in various cellula...

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“…Areas of inert PG in the side wall were also observed and are thought to act as de novo poles around which new cell wall material is incorrectly oriented, resulting in branch formation (42). Interestingly, the poles of rodshaped cells not only are metabolically inert for PG but also constitute an area of restricted mobility for periplasmic proteins (55) and outer membrane proteins (39,42). A leap forward in the visualization of nascent PG was achieved recently by work of Daniel and Errington, who developed a novel high-resolution staining method to label nascent PG in gram-positive bacteria by using a fluorescent derivative of the antibiotic vancomycin (Van-FL) (31) (Fig.…”

Section: Pbp2xmentioning

confidence: 99%

Bacterial Cell Wall Synthesis: New Insights from Localization Studies

Scheffers

Pinho

2005

Microbiol Mol Biol Rev

532

489

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SUMMARY In order to maintain shape and withstand intracellular pressure, most bacteria are surrounded by a cell wall that consists mainly of the cross-linked polymer peptidoglycan (PG). The importance of PG for the maintenance of bacterial cell shape is underscored by the fact that, for various bacteria, several mutations affecting PG synthesis are associated with cell shape defects. In recent years, the application of fluorescence microscopy to the field of PG synthesis has led to an enormous increase in data on the relationship between cell wall synthesis and bacterial cell shape. First, a novel staining method enabled the visualization of PG precursor incorporation in live cells. Second, penicillin-binding proteins (PBPs), which mediate the final stages of PG synthesis, have been localized in various model organisms by means of immunofluorescence microscopy or green fluorescent protein fusions. In this review, we integrate the knowledge on the last stages of PG synthesis obtained in previous studies with the new data available on localization of PG synthesis and PBPs, in both rod-shaped and coccoid cells. We discuss a model in which, at least for a subset of PBPs, the presence of substrate is a major factor in determining PBP localization.

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Compartmentalization of the periplasm at cell division sites in Escherichia coli as shown by fluorescence photobleaching experiments

Cited by 41 publications

References 22 publications

Restricted Mobility of Cell Surface Proteins in the Polar Regions of Escherichia coli

Restricted Mobility of Cell Surface Proteins in the Polar Regions of Escherichia coli

Translocation of Jellyfish Green Fluorescent Protein via the Tat System of Escherichia coli and Change of Its Periplasmic Localization in Response to Osmotic Up-shock

Bacterial Cell Wall Synthesis: New Insights from Localization Studies

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