title: Actin-based confinement of calcium responses during Shigella invasion.
abstract: Shigella, the agent of bacillary dysentery, invades epithelial cells by locally inducing actin reorganization. Upon cell invasion, Shigella induces calcium (Ca(2+)) signalling, but its role in invasion has remained unclear. Here we show that components involved in inositol 1, 4, 5- trisphosphate (InsP3) signalling are implicated in Shigella invasion. Although global Ca(2+) responses are dispensable for bacterial invasion, local Ca(2+) responses of unprecedented long duration are associated with invasion sites. Fluorescence recovery after photo-bleaching experiments indicate that diffusion of small solutes is hindered at Shigella-invasion sites and that diffusion hindrance is dependent on bacterially induced actin reorganization. Computational simulations and experimental challenge of the model support the notion that local accumulation of InsP3 permitted by restricted diffusion and enrichment of InsP3 receptors account for sustained local Ca(2+) increases at entry sites. Thus, cytoskeletal reorganization through diffusion hindrance shapes the duration of local Ca(2+) signals.
authors: Equipe Communication Intercellulaire et Infections Microbiennes. Centre de Recherche Interdisciplinaire en Biologie (CIRB). Collège de France. 11 Place Marcelin Berthelot, Paris 75005, France. guy.tran-van-nhieu@college-de-France.fr
authors: Guy
authors: G
authors: Tran Van Nhieu
authors: Bing
authors: B
authors: Kai Liu
authors: Jie
authors: J
authors: Zhang
authors: Fabienne
authors: F
authors: Pierre
authors: Sylvie
authors: S
authors: Prigent
authors: Philippe
authors: P
authors: Sansonetti
authors: Christophe
authors: C
authors: Erneux
authors: Jung
authors: J
authors: Kuk Kim
authors: Pann-Ghill
authors: PG
authors: Suh
authors: Geneviève
authors: G
authors: Dupont
authors: Laurent
authors: L
authors: Combettes
mesh_terms: D000199:Actins / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D004058:Diffusion; D036681:Fluorescence Recovery After Photobleaching; D006367:HeLa Cells; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism; D008954:Models, Biological; D012760:Shigella / Q000502:physiology*; D015398:Signal Transduction
chemical_list: D000199:Actins; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium