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The target cell plasma membrane is a critical interface for Salmonella cell entry effector-host interplay
Robert J Cain1, Richard D Hayward, Vassilis Koronakis
1University of Cambridge, Department of Pathology, Tennis Court Road, Cambridge CB2 1QP, UK.
Molecular Microbiology
|November 4, 2004
Summary
Salmonella effectors target the host cell membrane, not the cytosol, to rearrange the actin cytoskeleton for bacterial entry. Host Cdc42 is crucial for effector membrane association, revealing a key interaction site.
Area of Science:
- Microbiology
- Cell Biology
- Molecular Biology
Background:
- Salmonella Typhimurium invades non-phagocytic intestinal cells by inducing membrane ruffling.
- Bacterial effector proteins delivered via type III secretion systems manipulate host actin dynamics.
- The spatial and temporal coordination of six translocated effectors remains poorly understood.
Purpose of the Study:
- To investigate the subcellular localization of Salmonella translocated effectors.
- To understand how effectors coordinate cytoskeletal rearrangements for bacterial internalization.
- To identify host factors involved in effector-host cell interactions.
Main Methods:
- Mechanical cell fractionation to isolate cellular compartments.
- Immunofluorescence microscopy to visualize epitope-tagged effectors.
- In vitro assays using prenylated GTPase Cdc42.
Main Results:
- All six translocated Salmonella effectors localized to the host plasma membrane, not the cytosol.
- Effectors at the cell periphery induced distinct actin cytoskeleton rearrangements.
- Host GTPase Cdc42 is essential for the membrane association of SopE and SptP.
Conclusions:
- The host plasma membrane is a critical interface for Salmonella effector-host cell interactions.
- Effectors act at the cell periphery to manipulate the actin cytoskeleton.
- Host factors like Cdc42 are key mediators of effector function and localization.