Target cell contact triggers expression and polarized transfer of Yersinia YopE cytotoxin into mammalian cells.

Abstract

Pathogenic bacteria of the species Yersinia, including Yersinia pestis, block phagocytosis by macrophages. This process involves the YopE protein, which induces disruption of the host cell actin microfilament structure. Here, we show that the contact between the pathogen and the mammalian cell induces expression and then polarized transfer of YopE into the eukaryotic cell. While the bacteria remain at the surface of the target cell, the YopE cytotoxin is transferred through the host cell plasma membrane and YopE is only recovered within the cytosol of the target cell. The results suggest that the pathogen senses cell structures and focuses the transfer of YopE to occur solely at the interaction zone between the bacterium and the eukaryotic cell. The regulation of this process is shown to involve surface‐located YopN sensor protein of the bacterium.

YopK of Yersinia pseudotuberculosis controls translocation of Yop effectors across the eukaryotic cell membrane

“…Frithz-Lindsten, unpublished). This principle was first demonstrated for the Yop ( Yersinia outer protein) virulence determinants of Yersinia (Rosqvist et al, 1994;Sory and Cornelis, 1994) and infection of cells with this pathogen is also the most extensively studied model system for this mechanism. The secretion of Yops across the bacterial membranes is mediated by a type III secretion system (Salmond et al, 1993) encoded by the ysc genes (for a review, see Cornelis, 1992;Straley et al, 1993;Forsberg et al, 1994b).…”

Total Synthesis of the Resveratrol Oligomers (±)‐Ampelopsin B and (±)‐ϵ‐Viniferin

“…We recently discovered that (–)‐hopeaphenol ( 1 ), a tetramer of resveratrol ( 2 ) (Figure 1) isolated from the stem bark of Hopea hainanensis , inhibits the type III secretion system1 (T3SS) in Yersinia pseudotuberculosis and Pseudomonas aeruginosa 2. The conserved3 T3SS is critical for these pathogens to cause disease and therefore constitutes an attractive target for the development of new antibacterials 4.…”

The outer membrane component, YscC, of the Yop secretion machinery of Yersinia enterocolitica forms a ring‐shaped multimeric complex

“…Under these conditions, the cells display a growth arrest and secrete the Yops in high amounts. The YopN protein is a good candidate to be the sensor of the cell signal as the protein is located on the bacterial surface, and yopN mutants export the Yops in the absence of cell contact or Ca 2þ limitation (Forsberg et al, 1991;Rosqvist et al, 1994;Boland et al, 1996). Transcription of the yop genes is not only repressed by Ca 2þ but also by mutations in loci encoding components of the secretion machinery (Cornelis et al, 1987).…”