title: Quantitative insights into actin rearrangements and bacterial target site selection from Salmonella Typhimurium infection of micropatterned cells.
abstract: Reorganization of the host cell actin cytoskeleton is crucial during pathogen invasion. We established micropatterned cells as a standardized infection model for cell invasion to quantitatively study actin rearrangements triggered by Salmonella Typhimurium (S. Tm). Micropatterns of extracellular matrix proteins force cells to adopt a reproducible shape avoiding strong cell-to-cell variations, a major limitation in classical cell culture conditions. S. Tm induced F-actin-rich ruffles and invaded micropatterned cells similar to unconstrained cells. Yet, standardized conditions allowed fast and unbiased comparison of cellular changes triggered by the SipA and SopE bacterial effector proteins. Intensity measurements in defined regions revealed that the content of pre-existing F-actin remained unchanged during infection, suggesting that newly polymerized F-actin in bacteria-triggered ruffles originates from the G-actin pool. Analysing bacterial target sites, we found that bacteria did not show any preferences for the local actin cytoskeleton specificities. Rather, invasion was constrained to a specific 'cell height', due to flagella-mediated near-surface swimming. We found that invasion sites were similar to bacterial binding sites, indicating that S. Tm can induce a permissive invasion site wherever it binds. As micropatterned cells can be infected by many different pathogens they represent a valuable new tool for quantitative analysis of host-pathogen interactions.
authors: Institute of Microbiology, ETH Zürich, Wolfgang-Pauli-Str. 12, 8093, Zürich, Switzerland.
authors: Pascale
authors: P
authors: Vonaesch
authors: Steven
authors: S
authors: Cardini
authors: Mikael E
authors: ME
authors: Sellin
authors: Bruno
authors: B
authors: Goud
authors: Wolf-Dietrich
authors: WD
authors: Hardt
authors: Kristine
authors: K
authors: Schauer
mesh_terms: D000199:Actins / Q000378:metabolism*; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000378:metabolism; D003584:Cytological Techniques / Q000379:methods; D003599:Cytoskeleton / Q000378:metabolism*; D004705:Endocytosis; D004847:Epithelial Cells / Q000378:metabolism / Q000382:microbiology; D006367:HeLa Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism; D012486:Salmonella typhimurium / Q000502:physiology*
chemical_list: D000199:Actins; D001426:Bacterial Proteins; D008840:Microfilament Proteins; C118287:SipA protein, Salmonella; C103987:SopE protein, Salmonella