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Bead Aggregation Assays for the Characterization of Putative Cell Adhesion Molecules
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Bead Aggregation Assays for the Characterization of Putative Cell Adhesion Molecules

Published on: October 17, 2014

A novel group of Moraxella catarrhalis UspA proteins mediates cellular adhesion via CEACAMs and vitronectin

Darryl J Hill1, Cheryl Whittles, Mumtaz Virji

  • 1School of Cellular & Molecular Medicine, University of Bristol, Bristol, United Kingdom. Darryl.J.Hill@bristol.ac.uk

Plos One
|October 11, 2012
PubMed

Insights

Moraxella catarrhalis surface proteins can swap functional regions, creating new variants like UspA2V. These variants enhance bacterial adhesion and immune evasion, revealing greater UspA protein diversity.

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Molecular Biology

Background:

  • Moraxella catarrhalis (Mx) is a significant cause of otitis media and COPD exacerbations.
  • Surface proteins UspA1 and UspA2 mediate Mx adhesion to human receptors, playing a role in pathogenesis.
  • Genetic recombination can create hybrid UspA proteins (UspA2H), but functional exchange is poorly understood.

Purpose of the Study:

  • To investigate the potential for functional region exchange between Moraxella catarrhalis UspA1 and UspA2 adhesins.
  • To identify novel UspA variants and characterize their adhesive properties.

Main Methods:

  • Genetic analysis of Moraxella catarrhalis isolates.
  • Characterization of UspA protein variants, including UspA2V.
  • Assays to determine binding to CEACAMs and integrins via vitronectin.

Main Results:

  • Moraxella catarrhalis can incorporate the UspA1 CEACAM-binding region into UspA1 and UspA2 proteins.
  • Novel UspA2 Variant (UspA2V) proteins were identified in approximately 14% of isolates.
  • UspA2/2V variants with the CEACAM-binding domain facilitate binding to CEACAMs and integrins through vitronectin.

Conclusions:

  • The UspA protein family in Moraxella catarrhalis is more diverse than previously recognized.
  • Functional regions can be exchanged between UspA proteins in vivo, leading to novel adhesive capabilities.
  • These exchanges may enhance bacterial pathogenesis and immune evasion strategies.

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