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The Chlamydia effector TarP mimics the mammalian leucine-aspartic acid motif of paxillin to subvert the focal adhesion kinase during invasion.

Thwaites T, Nogueira AT, Campeotto I, Silva AP, Grieshaber SS, Carabeo RA - J. Biol. Chem. (2014)

Bottom Line: The conserved leucine residues within the L(D/E)XLLXXL motif were essential to the recruitment of FAK, Cdc42, p34(Arc), and actin to the plasma membrane.In the absence of FAK, TarP-LD-mediated F-actin assembly was reduced, highlighting the functional relevance of this interaction.Together, the data indicate that a prokaryotic version of the paxillin LD2 domain targets the FAK signaling pathway, with TarP representing the first example of an LD-containing Type III virulence effector.

View Article: PubMed Central - PubMed

Affiliation: From the Centre for Molecular Microbiology and Infection, Imperial College, London SW7 2AZ, United Kingdom, Bacteriology Section, Programme in Microbiology, Institute of Medical Sciences, School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom, and.

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The TarP-LD domain does not recruit actin or p34Arc in cells lacking FAK.A, FAK−/− cells can support pedestal structures induced by EPEC, indicating that actin recruitment and polymerization (white arrows) to the plasma membrane remained functional in the FAK−/− background. Scale bars, 10 μm. B, FAK+/+ and FAK−/− MEFs expressing TirM-LD were infected with Δtir EPEC, and actin remodeling and p34Arc recruitment were monitored. The white arrowheads indicate colocalization or lack thereof of actin and p34Arc with Δtir EPEC. Scale bars, 10 μm. C, colocalization of actin with Δtir EPEC was enumerated, and data are represented as a box and whisker plot. D, enumeration of Δtir EPEC colocalization with p34Arc with data represented as a box and whisker plot. Data were compiled from three independent experiments. A range of 550–700 particles for each was counted. The asterisk indicates statistical significance (ANOVA; Actin and p34Arc: p < 0.005 and post hoc testing Tukey-Kramer; α = 0.01, q = 3.76).
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Figure 7: The TarP-LD domain does not recruit actin or p34Arc in cells lacking FAK.A, FAK−/− cells can support pedestal structures induced by EPEC, indicating that actin recruitment and polymerization (white arrows) to the plasma membrane remained functional in the FAK−/− background. Scale bars, 10 μm. B, FAK+/+ and FAK−/− MEFs expressing TirM-LD were infected with Δtir EPEC, and actin remodeling and p34Arc recruitment were monitored. The white arrowheads indicate colocalization or lack thereof of actin and p34Arc with Δtir EPEC. Scale bars, 10 μm. C, colocalization of actin with Δtir EPEC was enumerated, and data are represented as a box and whisker plot. D, enumeration of Δtir EPEC colocalization with p34Arc with data represented as a box and whisker plot. Data were compiled from three independent experiments. A range of 550–700 particles for each was counted. The asterisk indicates statistical significance (ANOVA; Actin and p34Arc: p < 0.005 and post hoc testing Tukey-Kramer; α = 0.01, q = 3.76).

Mentions: Next, the functional relationship between FAK and the TarP-LD-dependent actin remodeling was investigated in FAK−/− MEFs. Demonstration of FAK-dependent actin remodeling by TarP-LD would support a signaling function for this domain. First, because of the potential actin-related signaling abnormalities the FAK−/− MEFs may have, including the hyper-activation of the RhoA GTPase (47), it was necessary to confirm that these cells remained competent in signaling from the plasma membrane to the actin cytoskeleton. Early-passage FAK+/+ and FAK−/− cells, directly obtained from the American Type Culture Collection, were infected with wild type EPEC, and actin-rich pedestal formation was monitored. As shown in Fig. 7A, FAK−/− cells supported EPEC pedestal formation, indicating that one or more signaling pathways to induce actin remodeling at the plasma membrane remained intact.


The Chlamydia effector TarP mimics the mammalian leucine-aspartic acid motif of paxillin to subvert the focal adhesion kinase during invasion.

Thwaites T, Nogueira AT, Campeotto I, Silva AP, Grieshaber SS, Carabeo RA - J. Biol. Chem. (2014)

The TarP-LD domain does not recruit actin or p34Arc in cells lacking FAK.A, FAK−/− cells can support pedestal structures induced by EPEC, indicating that actin recruitment and polymerization (white arrows) to the plasma membrane remained functional in the FAK−/− background. Scale bars, 10 μm. B, FAK+/+ and FAK−/− MEFs expressing TirM-LD were infected with Δtir EPEC, and actin remodeling and p34Arc recruitment were monitored. The white arrowheads indicate colocalization or lack thereof of actin and p34Arc with Δtir EPEC. Scale bars, 10 μm. C, colocalization of actin with Δtir EPEC was enumerated, and data are represented as a box and whisker plot. D, enumeration of Δtir EPEC colocalization with p34Arc with data represented as a box and whisker plot. Data were compiled from three independent experiments. A range of 550–700 particles for each was counted. The asterisk indicates statistical significance (ANOVA; Actin and p34Arc: p < 0.005 and post hoc testing Tukey-Kramer; α = 0.01, q = 3.76).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4215226&req=5

Figure 7: The TarP-LD domain does not recruit actin or p34Arc in cells lacking FAK.A, FAK−/− cells can support pedestal structures induced by EPEC, indicating that actin recruitment and polymerization (white arrows) to the plasma membrane remained functional in the FAK−/− background. Scale bars, 10 μm. B, FAK+/+ and FAK−/− MEFs expressing TirM-LD were infected with Δtir EPEC, and actin remodeling and p34Arc recruitment were monitored. The white arrowheads indicate colocalization or lack thereof of actin and p34Arc with Δtir EPEC. Scale bars, 10 μm. C, colocalization of actin with Δtir EPEC was enumerated, and data are represented as a box and whisker plot. D, enumeration of Δtir EPEC colocalization with p34Arc with data represented as a box and whisker plot. Data were compiled from three independent experiments. A range of 550–700 particles for each was counted. The asterisk indicates statistical significance (ANOVA; Actin and p34Arc: p < 0.005 and post hoc testing Tukey-Kramer; α = 0.01, q = 3.76).
Mentions: Next, the functional relationship between FAK and the TarP-LD-dependent actin remodeling was investigated in FAK−/− MEFs. Demonstration of FAK-dependent actin remodeling by TarP-LD would support a signaling function for this domain. First, because of the potential actin-related signaling abnormalities the FAK−/− MEFs may have, including the hyper-activation of the RhoA GTPase (47), it was necessary to confirm that these cells remained competent in signaling from the plasma membrane to the actin cytoskeleton. Early-passage FAK+/+ and FAK−/− cells, directly obtained from the American Type Culture Collection, were infected with wild type EPEC, and actin-rich pedestal formation was monitored. As shown in Fig. 7A, FAK−/− cells supported EPEC pedestal formation, indicating that one or more signaling pathways to induce actin remodeling at the plasma membrane remained intact.

Bottom Line: The conserved leucine residues within the L(D/E)XLLXXL motif were essential to the recruitment of FAK, Cdc42, p34(Arc), and actin to the plasma membrane.In the absence of FAK, TarP-LD-mediated F-actin assembly was reduced, highlighting the functional relevance of this interaction.Together, the data indicate that a prokaryotic version of the paxillin LD2 domain targets the FAK signaling pathway, with TarP representing the first example of an LD-containing Type III virulence effector.

View Article: PubMed Central - PubMed

Affiliation: From the Centre for Molecular Microbiology and Infection, Imperial College, London SW7 2AZ, United Kingdom, Bacteriology Section, Programme in Microbiology, Institute of Medical Sciences, School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom, and.

Show MeSH
Related in: MedlinePlus