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Neisseria meningitidis App, a new adhesin with autocatalytic serine protease activity

Davide Serruto1, Jeannette Adu-Bobie, Maria Scarselli

  • 1IRIS, Chiron S. r.l., via Fiorentina 1, 53100 Siena, Italy.

Molecular Microbiology
|April 5, 2003
PubMed

Insights

Adhesion and penetration protein (App) from Neisseria meningitidis mediates bacterial adherence to human epithelial cells. This autotransporter protein, expressed in E. coli, has its binding domain in the carboxy-terminal region.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Bacterial Pathogenesis

Background:

  • Neisseria meningitidis colonizes the respiratory tract and can cause sepsis and meningitis.
  • Molecules mediating N. meningitidis host cell interactions are largely unknown.
  • App (Adhesion and penetration protein) is an autotransporter homologous to H. influenzae Hap protein.

Purpose of the Study:

  • To analyze the functional properties of the App protein.
  • To confirm App's role in bacterial adhesion to host cells.

Main Methods:

  • Expressed app gene in Escherichia coli.
  • Analyzed App protein localization, processing, and release.
  • Tested adhesion of App-expressing E. coli to Chang epithelial cells.
  • Confirmed App's role in N. meningitidis adhesion.

Main Results:

  • App protein was exported to the E. coli surface and released into the supernatant.
  • E. coli expressing App demonstrated adherence to Chang epithelial cells.
  • App's serine protease activity is in the amino-terminal domain; binding domain is in the carboxy-terminal region.
  • App was confirmed to mediate adhesion in N. meningitidis.

Conclusions:

  • App is a functional autotransporter protein mediating bacterial adhesion to host cells.
  • App's distinct functional domains (protease and binding) were identified.
  • App plays a role in N. meningitidis adhesion to human epithelial cells.

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