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Chlamydia trachomatis tarp is phosphorylated by src family tyrosine kinases

Travis J Jewett1, Cheryl A Dooley, David J Mead

  • 1Host-Parasite Interactions Section, Laboratory of Intracellular Parasites, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, 903 South 4th Street, Hamilton, MT 59840, USA.

Biochemical and Biophysical Research Communications
|April 30, 2008
PubMed

Insights

Chlamydia trachomatis translocated actin-recruiting phosphoprotein (Tarp) is phosphorylated by host kinases like Src and Abl. However, inhibiting these kinases did not affect bacterial entry into host cells.

Area of Science:

  • Microbiology
  • Cell Biology
  • Biochemistry

Background:

  • Chlamydia trachomatis injects translocated actin-recruiting phosphoprotein (Tarp) into host cells post-attachment.
  • Tarp phosphorylation by host cell tyrosine kinases is crucial, but the specific kinases and its role in bacterial entry remain unclear.

Purpose of the Study:

  • To identify host cell kinases responsible for Tarp phosphorylation.
  • To investigate the role of Tarp phosphorylation in Chlamydia trachomatis entry into host cells.

Main Methods:

  • Utilized recombinant C. trachomatis Tarp for in vitro kinase assays.
  • Employed Src, Abl, Yes, and Fyn kinases to test Tarp phosphorylation.
  • Performed mutagenesis on Tarp tyrosine residues.
  • Inhibited Src and Abl kinases using chemical inhibitors in cell culture.

Main Results:

  • Recombinant Tarp was phosphorylated by purified Src, Abl, Yes, and Fyn kinases.
  • Mutagenesis studies suggested Src and Abl kinases phosphorylate the same Tarp residues.
  • Inhibition of Src and Abl kinases blocked Tarp phosphorylation in cultured cells.
  • Blocking Tarp phosphorylation did not impede Chlamydia trachomatis entry into host cells.

Conclusions:

  • C. trachomatis Tarp serves as a substrate for multiple host cell kinases, including Src and Abl.
  • Tarp phosphorylation by Src and Abl kinases is not essential for Chlamydia trachomatis invasion of host cells.

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