PMID:19346310

Citation	Varma, A and Young, KD (2009) In Escherichia coli, MreB and FtsZ direct the synthesis of lateral cell wall via independent pathways that require PBP 2. J. Bacteriol. 191:3526-33
Abstract	In Escherichia coli, the cytoplasmic proteins MreB and FtsZ play crucial roles in ensuring that new muropeptide subunits are inserted into the cell wall in a spatially correct way during elongation and division. In particular, to retain a constant diameter and overall shape, new material must be inserted into the wall uniformly around the cell's perimeter. Current thinking is that MreB accomplishes this feat through intermediary proteins that tether peptidoglycan synthases to the outer face of the inner membrane. We tested this idea in E. coli by using a DD-carboxypeptidase mutant that accumulates pentapeptides in its peptidoglycan, allowing us to visualize new muropeptide incorporation. Surprisingly, inhibiting MreB with the antibiotic A22 did not result in uneven insertion of new wall, although the cells bulged and lost their rod shapes. Instead, uneven (clustered) incorporation occurred only if MreB and FtsZ were inactivated simultaneously, providing the first evidence in E. coli that FtsZ can direct murein incorporation into the lateral cell wall independently of MreB. Inhibiting penicillin binding protein 2 (PBP 2) alone produced the same clustered phenotype, implying that MreB and FtsZ tether peptidoglycan synthases via a common mechanism that includes PBP 2. However, cell shape was determined only by the presence or absence of MreB and not by the even distribution of new wall material as directed by FtsZ.
Links	PubMed PMC2681889 Online version:10.1128/JB.01812-08
Keywords	Arabinose/pharmacology; Aztreonam/pharmacology; Bacterial Proteins/metabolism; Cell Wall/drug effects; Cell Wall/metabolism; Cytoskeletal Proteins/metabolism; Escherichia coli/cytology; Escherichia coli/drug effects; Escherichia coli/metabolism; Escherichia coli Proteins/antagonists & inhibitors; Escherichia coli Proteins/genetics; Escherichia coli Proteins/metabolism; Escherichia coli Proteins/physiology; Microscopy, Confocal; Models, Biological; Penicillin-Binding Proteins/antagonists & inhibitors; Penicillin-Binding Proteins/physiology; Peptidoglycan/metabolism; Thiourea/analogs & derivatives; Thiourea/pharmacology
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ECOLI:FTSZ		GO:0043164: Gram-negative-bacterium-type cell wall biogenesis	ECO:0000316:	UniProtKB:P0A9A6	P		Table 1 strain 3 In the absence of MreB, FtsZ can tether and direct a generalized and evenly dispersed peptidoglycan, via a PBP2 pathway, producing a spherical-shaped cell	complete CACAO 3945
ECOLI:MREB		GO:0043164: Gram-negative-bacterium-type cell wall biogenesis	ECO:0000316:	UniProtKB:P0A9A6	P		Table 1 Strain 2 MreB can tether peptidoglycan synthesis via a PBP2 pathway independently of FtsZ, producing a rod-shaped cell	complete CACAO 3943
ECOLI:MREB		GO:0005200: structural constituent of cytoskeleton	ECO:0000270:		F		Fig 2	complete CACAO 3675

References

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