Lamellipodin Is Important for Cell-to-Cell Spread and Actin-Based Motility in Listeria monocytogenes.

Jiahui Wang,Marie Goldrick,Ian S Roberts,Frank B Gertler,Martin Lowe,Jane E King,A Camilli

doi:10.1128/iai.00193-15

Jiahui Wang, Marie Goldrick + Show 5 more

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https://doi.org/10.1128/iai.00193-15

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Abstract

Listeria monocytogenes is a foodborne pathogen capable of invading a broad range of cell types and replicating within the host cell cytoplasm. This paper describes the colocalization of host cell lamellipodin (Lpd) with intracellular L. monocytogenes detectable 6 h postinfection of epithelial cells. The association was mediated via interactions between both the peckstrin homology (PH) domain in Lpd and phosphatidylinositol (3,4)-bisphosphate [PI(3,4)P2] on the bacterial surface and by interactions between the C-terminal EVH1 (Ena/VASP [vasodilator-stimulated phosphoprotein] homology domain 1) binding domains of Lpd and the host VASP (vasodilator-stimulated phosphoprotein) recruited to the bacterial cell surface by the listerial ActA protein. Depletion of Lpd by short interfering RNA (siRNA) resulted in reduced plaque size and number, indicating a role for Lpd in cell-to-cell spread. In contrast, overexpression of Lpd resulted in an increase in the number of L. monocytogenes-containing protrusions (listeriopods). Manipulation of the levels of Lpd within the cell also affected the intracellular velocity of L. monocytogenes, with a reduction in Lpd corresponding to an increase in intracellular velocity. These data, together with the observation that Lpd accumulated at the interface between the bacteria and the developing actin tail at the initiation of actin-based movement, indicate a possible role for Lpd in the actin-based movement and the cell-to-cell spread of L. monocytogenes.

Highlights

Listeria monocytogenes is a foodborne pathogen capable of invading a broad range of cell types and replicating within the host cell cytoplasm
To determine if Lpd was associated with L. monocytogenes at later time points following infection of HeLa cells, HeLa cells were transfected with pEGFP-C1hLPD encoding GFP-tagged Lpd 24 h prior to infection
In infected HeLa cells treated with cytochalasin D, which inhibited the formation of F-actin tails, Lpd was still recruited to the surface of L. monocytogenes in 97.02% Ϯ 3.53% of the actin-associated bacteria, predominantly to one pole of the cell (Fig. 1D)

Summary

Introduction

Listeria monocytogenes is a foodborne pathogen capable of invading a broad range of cell types and replicating within the host cell cytoplasm. VASP is found at sites of active actin polymerization and is a substrate for cyclic GMP (cGMP)- or cyclic AMP (cAMP)-dependent kinases [16] It can recruit profilin, provide polymerization-competent actin monomers to the N terminus of ActA [13], and interact with F-actin through its C-terminal EVH2 domain, providing a linkage of the bacterium to the tail [15]. L. monocytogenes spreads from cell to cell through the generation of bacterial protrusions that are engulfed in the adjacent cell followed by escape into the cytosol of the newly infected cell [11] This is the least-well-understood stage of the intracellular life cycle of L. monocytogenes. One possible candidate for playing a role in cell-to-cell spread is Lpd, which is known to play a critical role in cell migration, 3740 iai.asm.org

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