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The Chlamydia pneumoniae invasin protein Pmp21 recruits the EGF receptor for host cell entry

Katja Mölleken1, Elisabeth Becker, Johannes H Hegemann

  • 1Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine Universität, Düsseldorf, Germany.

Plos Pathogens
|May 2, 2013
PubMed

Insights

Chlamydia pneumoniae uses the Pmp21 protein as an invasin to bind to the EGFR receptor on host cells. This interaction is crucial for the internalization of elementary bodies and subsequent infection.

Area of Science:

  • Microbiology
  • Cell Biology
  • Infectious Diseases

Background:

  • Chlamydiae are obligate intracellular bacteria requiring host cell entry.
  • The molecular mechanisms of Chlamydia Elementary Body (EB) internalization were previously unknown.

Purpose of the Study:

  • To identify the specific invasin and host cell receptor involved in Chlamydia pneumoniae entry.
  • To elucidate the signaling pathways triggered by Chlamydia EB interaction with host cells.

Main Methods:

  • Identified Chlamydia pneumoniae Pmp21 as an invasin and Epidermal Growth Factor Receptor (EGFR) as its host cell receptor.
  • Manipulated EGFR expression in cells to assess its role in EB adhesion, internalization, and infectivity.
  • Investigated downstream signaling pathways including Grb2, c-Cbl, and ERK1/2 activation.

Main Results:

  • Pmp21 mediates EB binding and internalization via EGFR.
  • EGFR expression levels directly correlate with EB adhesion, internalization, and infectivity.
  • EGFR activation leads to recruitment of Grb2 and c-Cbl, and subsequent ERK1/2 activation, which is essential for EB entry.

Conclusions:

  • This study identifies the first known invasin-receptor interaction for host cell invasion by any Chlamydia species.
  • Pmp21-EGFR interaction is critical for Chlamydia pneumoniae infection, highlighting a novel therapeutic target.

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