Regulation of Peptidoglycan Synthesis by Outer-Membrane Proteins

Cell. 2010 Dec 23;143(7):1097-109. doi: 10.1016/j.cell.2010.11.038.

Abstract

Growth of the mesh-like peptidoglycan (PG) sacculus located between the bacterial inner and outer membranes (OM) is tightly regulated to ensure cellular integrity, maintain cell shape, and orchestrate division. Cytoskeletal elements direct placement and activity of PG synthases from inside the cell, but precise spatiotemporal control over this process is poorly understood. We demonstrate that PG synthases are also controlled from outside of the sacculus. Two OM lipoproteins, LpoA and LpoB, are essential for the function, respectively, of PBP1A and PBP1B, the major E. coli bifunctional PG synthases. Each Lpo protein binds specifically to its cognate PBP and stimulates its transpeptidase activity, thereby facilitating attachment of new PG to the sacculus. LpoB shows partial septal localization, and our data suggest that the LpoB-PBP1B complex contributes to OM constriction during cell division. LpoA/LpoB and their PBP-docking regions are restricted to γ-proteobacteria, providing models for niche-specific regulation of sacculus growth.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Outer Membrane Proteins / chemistry
  • Bacterial Outer Membrane Proteins / metabolism*
  • Cell Division
  • Cell Wall / metabolism
  • Escherichia coli / cytology*
  • Escherichia coli / enzymology
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / metabolism*
  • Lipoproteins / chemistry
  • Lipoproteins / metabolism
  • Penicillin-Binding Proteins / metabolism
  • Peptidoglycan / biosynthesis*
  • Peptidoglycan Glycosyltransferase / metabolism
  • Protein Interaction Domains and Motifs

Substances

  • Bacterial Outer Membrane Proteins
  • Escherichia coli Proteins
  • FtsI protein, E coli
  • Lipoproteins
  • LpoB protein, E coli
  • Penicillin-Binding Proteins
  • Peptidoglycan
  • Peptidoglycan Glycosyltransferase