Entry of the bacterial pathogen Listeria monocytogenes into mammalian cells.
The bacterial pathogen Listeria monocytogenes causes food-borne illnesses leading to meningitis or abortion. Listeria provokes its internalization ('entry') into mammalian cells that are normally non-phagocytic, such as intestinal epithelial cells and hepatocytes. Entry provides access to a nutrient-rich cytosol and allows translocation across anatomical barriers. Here I discuss the two major internalization pathways used by Listeria. These pathways are initiated by binding of the bacterial surface proteins InlA or InlB to their respective host receptors, E-cadherin or Met. InlA mediates traversal of the intestinal barrier, whereas InlB promotes infection of the liver. At the cellular level, both InlA- and InlB-dependent entry require host signalling that promotes cytoskeletal rearrangements and pathogen engulfment. However, many of the specific signalling proteins in the two entry routes differ. InlA-mediated uptake uses components of adherens junctions that are coupled to F-actin and myosin, whereas InlB-dependent entry involves cytosolic adaptors that bridge Met to regulators of F-actin, including phosphoinositide 3-kinase and activators of the Arp2/3 complex. Unexpectedly, entry directed by InlB also involves endocytic components. Future work on InlA and InlB will lead to a better understanding of virulence, and may also provide novel insights into the normal biological functions of E-cadherin and Met.
Ireton
Keith
K
Department of Molecular Biology and Microbiology, Burnett College of Biomedical Sciences, University of Central Florida, Orlando, Fl 32826-3227, USA. kireton@mail.ucf.edu
D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism; D006801:Humans; D008089:Listeria monocytogenes / Q000378:metabolism / Q000472:pathogenicity*; D008088:Listeriosis / Q000382:microbiology*; D008565:Membrane Proteins / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D017978:Receptors, Growth Factor / Q000378:metabolism; D015398:Signal Transduction
D001426:Bacterial Proteins; D015820:Cadherins; D008565:Membrane Proteins; D017978:Receptors, Growth Factor; C095768:inlB protein, Listeria monocytogenes; C069761:internalin protein, Bacteria; D020794:Receptor Protein-Tyrosine Kinases