Microbiology

Rapid Transport

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Science  21 Oct 2011:
Vol. 334, Issue 6054, pp. 291
DOI: 10.1126/science.334.6054.291-a
CREDIT: NIKITAS AND LECUIT

E-cadherin is a species-specific receptor for the foodborne pathogen Listeria monocytogenes but it is located out of reach beneath the tight junctions formed between gut epithelial cells. Does the dynamic nature of the intestinal epithelium, which is being remodeled constantly, with cells being shed and mucus secreted, allow for E-cadherin to be accessed? Taking a step back from molecular studies of pathogen cell invasion, Nikitas et al. watched how Listeria invades the body, using humanized mice and two-photon and confocal microscopy. They found that E-cadherin is not perpetually out of sight but becomes exposed to the intestinal lumen when cells are extruded and cell junctions are disrupted by contracting goblet cells or folds in the villi. Once inside the cell, the bacteria have no need for any other virulence factors, neither listeriolysin-O nor ActA (which polymerizes the cell's actin). All that is required is the bacterial surface protein InlA for rapid apico-basal translocation mediated by the cell's microtubules and exocytosis into the lamina propria. Thirty minutes after invasion, and Listeria had entered the spleen undetected by immune surveillance and a systemic infection was established.

J. Exp. Med. 208, 10.1084/jem.20110560 (2011).

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