title: Bacterial genotoxins promote inside-out integrin β1 activation, formation of focal adhesion complexes and cell spreading.
abstract: Integrins are membrane bound receptors that regulate several cellular processes, such as cell adhesion, migration, survival and proliferation, and may contribute to tumor initiation/progression in cells exposed to genotoxic stress. The extent of integrin activation and its role in cell survival upon intoxication with bacterial genotoxins are still poorly characterized. These toxins induce DNA strand breaks in the target cells and activate the DNA damage response (DDR), coordinated by the Ataxia Telangectasia Mutated (ATM) kinase. In the present study, we demonstrate that induction of DNA damage by two bacterial genotoxins promotes activation of integrin β1, leading to enhanced assembly of focal adhesions and cell spreading on fibronectin, but not on vitronectin. This phenotype is mediated by an ATM-dependent inside-out integrin signaling, and requires the actin cytoskeleton remodeler NET1. The toxin-mediated cell spreading and anchorage-independent survival further relies on ALIX and TSG101, two components of the endosomal sorting complex required for transport (ESCRT), known to regulate integrin intracellular trafficking. These data reveal a novel aspect of the cellular response to bacterial genotoxins, and provide new tools to understand the carcinogenic potential of these effectors in the context of chronic intoxication and infection.
authors: Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
authors: Laura
authors: L
authors: Levi
authors: Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
authors: Tatsushi
authors: T
authors: Toyooka
authors: Department of Dental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors: Manuel
authors: M
authors: Patarroyo
authors: Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
authors: Teresa
authors: T
authors: Frisan
mesh_terms: D015153:Blotting, Western; D018938:Caco-2 Cells; D002448:Cell Adhesion / Q000187:drug effects* / Q000502:physiology; D002465:Cell Movement / Q000187:drug effects* / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects; D004731:Endotoxins / Q000494:pharmacology*; D005455:Fluorescent Antibody Technique; D022001:Focal Adhesions / Q000187:drug effects* / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism*; D009153:Mutagens / Q000494:pharmacology*; D012485:Salmonella typhi / Q000472:pathogenicity; D015398:Signal Transduction / Q000187:drug effects*; D014435:Typhoid Fever / Q000382:microbiology
chemical_list: D004731:Endotoxins; D019012:Integrin beta1; D009153:Mutagens; C027952:salmonella toxin