The morphogenetic MreBCD proteins of Escherichia coli form an essential membrane-bound complex
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The morphogenetic MreBCD proteins of Escherichia coli form an essential membrane-bound complex. / Kruse, Thomas; Bork-Jensen, Jette; Gerdes, Kenn.
In: Molecular Microbiology, Vol. 55, No. 1, 01.2005, p. 78-89.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - The morphogenetic MreBCD proteins of Escherichia coli form an essential membrane-bound complex
AU - Kruse, Thomas
AU - Bork-Jensen, Jette
AU - Gerdes, Kenn
PY - 2005/1
Y1 - 2005/1
N2 - MreB proteins of Escherichia coli, Bacillus subtilis and Caulobacter crescentus form actin-like cables lying beneath the cell surface. The cables are required to guide longitudinal cell wall synthesis and their absence leads to merodiploid spherical and inflated cells prone to cell lysis. In B. subtilis and C. crescentus, the mreB gene is essential. However, in E. coli, mreB was inferred not to be essential. Using a tight, conditional gene depletion system, we systematically investigated whether the E. coli mreBCD-encoded components were essential. We found that cells depleted of mreBCD became spherical, enlarged and finally lysed. Depletion of each mre gene separately conferred similar gross changes in cell morphology and viability. Thus, the three proteins encoded by mreBCD are all essential and function in the same morphogenetic pathway. Interestingly, the presence of a multicopy plasmid carrying the ftsQAZ genes suppressed the lethality of deletions in the mre operon. Using GFP and cell fractionation methods, we showed that the MreC and MreD proteins were associated with the cell membrane. Using a bacterial two-hybrid system, we found that MreC interacted with both MreB and MreD. In contrast, MreB and MreD did not interact in this assay. Thus, we conclude that the E. coli MreBCD form an essential membrane-bound complex. Curiously, MreB did not form cables in cell depleted for MreC, MreD or RodA, indicating a mutual interdependency between MreB filament morphology and cell shape. Based on these and other observations we propose a model in which the membrane-associated MreBCD complex directs longitudinal cell wall synthesis in a process essential to maintain cell morphology.
AB - MreB proteins of Escherichia coli, Bacillus subtilis and Caulobacter crescentus form actin-like cables lying beneath the cell surface. The cables are required to guide longitudinal cell wall synthesis and their absence leads to merodiploid spherical and inflated cells prone to cell lysis. In B. subtilis and C. crescentus, the mreB gene is essential. However, in E. coli, mreB was inferred not to be essential. Using a tight, conditional gene depletion system, we systematically investigated whether the E. coli mreBCD-encoded components were essential. We found that cells depleted of mreBCD became spherical, enlarged and finally lysed. Depletion of each mre gene separately conferred similar gross changes in cell morphology and viability. Thus, the three proteins encoded by mreBCD are all essential and function in the same morphogenetic pathway. Interestingly, the presence of a multicopy plasmid carrying the ftsQAZ genes suppressed the lethality of deletions in the mre operon. Using GFP and cell fractionation methods, we showed that the MreC and MreD proteins were associated with the cell membrane. Using a bacterial two-hybrid system, we found that MreC interacted with both MreB and MreD. In contrast, MreB and MreD did not interact in this assay. Thus, we conclude that the E. coli MreBCD form an essential membrane-bound complex. Curiously, MreB did not form cables in cell depleted for MreC, MreD or RodA, indicating a mutual interdependency between MreB filament morphology and cell shape. Based on these and other observations we propose a model in which the membrane-associated MreBCD complex directs longitudinal cell wall synthesis in a process essential to maintain cell morphology.
KW - Amino Acid Sequence
KW - Cell Membrane
KW - Escherichia coli
KW - Escherichia coli Proteins
KW - Genes, Bacterial
KW - Green Fluorescent Proteins
KW - Membrane Proteins
KW - Models, Molecular
KW - Molecular Sequence Data
KW - Protein Binding
KW - Suppression, Genetic
KW - Two-Hybrid System Techniques
U2 - 10.1111/j.1365-2958.2004.04367.x
DO - 10.1111/j.1365-2958.2004.04367.x
M3 - Journal article
C2 - 15612918
VL - 55
SP - 78
EP - 89
JO - Molecular Microbiology
JF - Molecular Microbiology
SN - 0950-382X
IS - 1
ER -
ID: 45524616