ARHGAP10 is necessary for -catenin recruitment at adherens junctions and for Listeria invasion

Sandra Sousa^1, 6, Didier Cabanes^1, 6, Cristel Archambaud¹, Frédéric Colland², Emmanuel Lemichez³, Michel Popoff⁴, Stéphanie Boisson-Dupuis¹, Edith Gouin¹, Marc Lecuit^1, 5, Pierre Legrain^3, 7 & Pascale Cossart¹

¹  Unité des Interactions Bactéries-Cellules Institut Pasteur, INSERM U604, INRA USC2020, 28 Rue du Dr Roux, 75724 Paris Cedex 15, France.

²  Hybrigenics SA, 3-5 Impasse Reille, 75014 Paris, France.

³  Bacterial toxins in host-pathogen interaction, Faculté de Médecine de Nice, 28 Avenue de Valombrose, Nice 06107 Cedex 02, France.

⁴  Unité Bacteries anaerobies et Toxines Institut Pasteur, Paris.

⁵  Service des Maladies Infectieuses et Tropicales, Hôpital Necker-Enfants Malades, 149 rue de Sèvres, 75015 Paris, France.

⁶  Present addresses: Institute for Molecular and Cell Biology, Molecular Microbiology, Rua do Campo Alegre 823, 4150-180 Porto, Portugal;

⁷  Département de Biologie Joliot-Curie, CEA, 91191 Gif-sur-Yvette CEDEX, France.

E-cadherin mediates the formation of adherens junctions between epithelial cells¹. It serves as a receptor for Listeria monocytogenes, a bacterial pathogen that enters epithelial cells². The L. monocytogenes surface protein, InlA, interacts with the extracellular domain of E-cadherin^{3, 4, 5}. In adherens junctions, this ectodomain is involved in homophilic interactions whereas the cytoplasmic domain binds -catenin, which then recruits -catenin. -catenin binds to actin directly, or indirectly, thus linking E-cadherin to the actin cytoskeleton^{6, 7}. Entry of L. monocytogenes into cells and adherens junction formation are dynamic events that involve actin and membrane rearrangements. To understand these processes better, we searched for new ligands of -catenin. Using a two-hybrid screen, we identified a new partner of -catenin: ARHGAP10. This protein colocalized with -catenin at cell−cell junctions and was recruited at L. monocytogenes entry sites. In ARHGAP10-knockdown cells, L. monocytogenes entry and -catenin recruitment at cell−cell contacts were impaired. The GAP domain of ARHGAP10 has GAP activity for RhoA and Cdc42. Its overexpression disrupted actin cables, enhanced -catenin and cortical actin levels at cell−cell junctions and inhibited L. monocytogenes entry. Altogether, our results show that ARHGAP10 is a new component of cell−cell junctions that controls -catenin recruitment and has a key role during L. monocytogenes uptake.

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