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Updated: May 23, 2026

Live-Cell Forward Genetic Approach to Identify and Isolate Developmental Mutants in Chlamydia trachomatis
Published on: June 10, 2020
Chlamydia trachomatis Tarp cooperates with the Arp2/3 complex to increase the rate of actin polymerization
Shahanawaz Jiwani1, Ryan J Ohr, Elizabeth R Fischer
1Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA.
Abstract:
Actin polymerization is required for Chlamydia trachomatis entry into nonphagocytic host cells. Host and chlamydial actin nucleators are essential for internalization of chlamydiae by eukaryotic cells. The host cell Arp2/3 complex and the chlamydial translocated actin recruiting phosphoprotein (Tarp) are both required for entry. Tarp and the Arp2/3 complex exhibit unique actin polymerization kinetics individually, but the molecular details of how these two actin nucleators cooperate to promote bacterial entry is not understood. In this study we provide biochemical evidence that the two actin nucleators act synergistically by co-opting the unique attributes of each to enhance the dynamics of actin filament formation. This process is independent of Tarp phosphorylation. We further demonstrate that Tarp colocalization with actin filaments is independent of the Tarp phosphorylation domain. The results are consistent with a model in which chlamydial and host cell actin nucleators cooperate to increase the rate of actin filament formation.
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