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Biomimetic Materials to Characterize Bacteria-host Interactions
12:22

Biomimetic Materials to Characterize Bacteria-host Interactions

Published on: November 16, 2015

FadA from Fusobacterium nucleatum utilizes both secreted and nonsecreted forms for functional oligomerization for

Minghua Xu1, Mitsunori Yamada, Mei Li

  • 1Department of Periodontics, Case Western Reserve University, Cleveland, Ohio 44106, USA.

The Journal of Biological Chemistry
|June 26, 2007
PubMed

Insights

Fusobacterium nucleatum uses a novel adhesin, FadA, in two forms (pre-FadA and mFadA) to bind and invade host cells. This dual-form adhesin mechanism is crucial for bacterial pathogenesis.

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Molecular Biology

Background:

  • Fusobacterium nucleatum is a Gram-negative anaerobe linked to human infections like periodontal disease and preterm birth.
  • A novel adhesin, FadA, has been identified in F. nucleatum, mediating host-cell interactions.

Purpose of the Study:

  • To investigate the structure, function, and host-cell binding mechanisms of the novel FadA adhesin from Fusobacterium nucleatum.
  • To elucidate the roles of the different forms of FadA in bacterial adhesion and invasion.

Main Methods:

  • Expression of FadA in Escherichia coli to study bacterial binding to host cells.
  • Purification and characterization of pre-FadA and mature FadA (mFadA) forms.
  • In vitro binding assays using fluorescence-labeled mFadA and epithelial cells.

Main Results:

  • FadA exists in two forms: membrane-anchored pre-FadA and secreted mFadA, forming complexes.
  • mFadA alone did not bind host cells, but binding and invasion occurred when co-administered with pre-FadA.
  • Pre-FadA is insoluble alone but becomes soluble when complexed with mFadA or at acidic pH.

Conclusions:

  • FadA functions as a unique bacterial adhesin/invasin utilizing two forms for structural and functional purposes.
  • The pre-FadA-mFadA complex, likely anchored in the inner membrane and protruding through the outer membrane, facilitates bacterial invasion.
  • Understanding FadA's mechanism is key to developing strategies against F. nucleatum-associated diseases.

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