The Cpx pathway causes changes in peptidoglycan structure, turnover, and recycling

• Author / Creator

  Bernal, María Margarita

• Bacteria need to adapt to the ever-changing conditions in the environment and Escherichia coli employs the Cpx two-component system to protect the envelope, which consists of the inner membrane, periplasm, peptidoglycan, and outer membrane. Cpx is known to sense and respond to protein misfolding in the periplasm and changes to the inner membrane. In this study, we investigate the effect of the activation of the Cpx pathway on the peptidoglycan (PG) structure. We confirm the CpxR-mediated regulation of amiA, amiC, dacC, slt, mltB, ygaU, and ycbB using luminescent reporters. In addition, we confirm that these genes are activated in response to Cpx-inducing conditions. HPLC analysis shows that activation of four genes – ycbB, ygaU, slt70 and mltB - leads to changes in peptidoglycan cross-linking and turn over. Furthermore, absence of ycbB and ygaU caused activation of the Cpx pathway, suggesting that changes in PG can induce this stress response.

• Subjects / Keywords

  • E. coli
  • Peptidoglycan
  • L,D-transpeptidases
  • Stress responses
  • Lytic transglycosylase
  • Cell wall
  • Cpx pathway

• Graduation date

  Spring 2014

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3794117W

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.