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The rickettsia surface cell antigen 4 applies mimicry to bind to and activate vinculin

HaJeung Park1, Jun Hyuck Lee, Edith Gouin

  • 1Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA.

The Journal of Biological Chemistry
|August 16, 2011
PubMed

Insights

Rickettsia surface antigen sca4 binds and activates vinculin, a key host cell protein. This interaction mimics a natural cellular process, aiding Rickettsia pathogenesis and host cell invasion.

Area of Science:

  • Microbiology
  • Cell Biology
  • Structural Biology

Background:

  • Pathogenic Rickettsia species, including R. prowazekii (typhus agent), cause significant disease.
  • Intracellular pathogens like Rickettsia utilize host cell cytoskeleton for invasion and spread.

Purpose of the Study:

  • To elucidate the mechanism by which Rickettsia surface antigen sca4 interacts with and manipulates the host cell cytoskeleton.
  • To investigate the role of sca4 in Rickettsia pathogenesis.

Main Methods:

  • Co-localization studies of sca4 with vinculin in transfected cells.
  • Biochemical assays to demonstrate sca4 binding and activation of vinculin.
  • Crystal structure determination of vinculin bound to sca4 VBS.

Main Results:

  • Rickettsia sca4 co-localizes with vinculin at focal adhesions.
  • Sca4 binds and activates vinculin via conserved Vinculin Binding Sites (VBSs), mimicking the vinculin-talin interaction.
  • Crystal structures reveal a novel vinculin conformation upon binding sca4.

Conclusions:

  • Sca4 activates vinculin through molecular mimicry, facilitating interaction with the actin cytoskeleton.
  • This mechanism is crucial for Rickettsia pathogenesis and host cell manipulation.
  • Vinculin plays a significant role in Rickettsia infection processes.

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