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Mammalian 14-3-3beta associates with the Chlamydia trachomatis inclusion membrane via its interaction with IncG

M A Scidmore1, T Hackstadt

  • 1Host-Parasite Interactions Section, Laboratory of Intracellular Parasites, National Institutes of Allergy and Infectious Diseases, Rocky Mountain Laboratories, Hamilton, MT 59840, USA.

Molecular Microbiology
|March 22, 2001
PubMed

Insights

Researchers discovered that Chlamydia trachomatis uses a host protein, 14-3-3beta, to interact with its inclusion membrane via the IncG protein. This interaction is specific to C. trachomatis and involves IncG phosphorylation.

Area of Science:

  • Microbiology
  • Cell Biology
  • Molecular Biology

Background:

  • Chlamydiae are obligate intracellular bacteria that reside within a modified vacuole.
  • Chlamydial inclusion membrane proteins (Inc) are crucial for modulating the host cell environment.
  • Four Inc proteins (IncD-G) are expressed early after infection.

Purpose of the Study:

  • To identify host proteins interacting with chlamydial inclusion membrane proteins.
  • To elucidate the mechanism of interaction between IncG and host factors.
  • To determine the specificity of host-pathogen interactions during Chlamydia infection.

Main Methods:

  • Yeast two-hybrid screening to identify interacting proteins.
  • Indirect immunofluorescence microscopy to confirm interactions in infected cells.
  • Co-immunoprecipitation and site-directed mutagenesis to analyze binding interfaces and phosphorylation.

Main Results:

  • The host protein 14-3-3beta specifically interacts with the chlamydial IncG protein.
  • IncG is phosphorylated and binds 14-3-3beta via a conserved motif.
  • 14-3-3beta interacts with Chlamydia trachomatis inclusions, but not those of C. psittaci or C. pneumoniae.

Conclusions:

  • 14-3-3beta is the first identified eukaryotic protein to interact with the chlamydial inclusion.
  • The interaction involves phosphorylation of IncG and a specific binding motif.
  • This interaction is specific to Chlamydia trachomatis, suggesting a role in its unique pathogenesis.

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