title: Chlamydia trachomatis Tarp cooperates with the Arp2/3 complex to increase the rate of actin polymerization.
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.
authors.affiliation: Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA.
authors.forename: Shahanawaz
authors.initials: S
authors.lastname: Jiwani
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Ohr
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Fischer
authors.forename: Ted
authors.initials: T
authors.lastname: Hackstadt
authors.forename: Stephenie
authors.initials: S
authors.lastname: Alvarado
authors.forename: Adriana
authors.initials: A
authors.lastname: Romero
authors.forename: Travis J
authors.initials: TJ
authors.lastname: Jewett
mesh_terms: D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism*; D000199:Actins / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D002692:Chlamydia trachomatis / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D010750:Phosphoproteins / Q000378:metabolism*; D058105:Polymerization
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; D001426:Bacterial Proteins; D010750:Phosphoproteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins