NO produced by activated macrophages inhibits expression of the Salmonella SPI2 system, which destines the bacteria (green) for degradation in late endosomes/lysosomes (red).
Salmonella is an enteric pathogen that infects macrophages and causes illnesses ranging from mild gastroenteritis to potentially fatal systemic disease. Once inside macrophages, Salmonella avoid the cells' antimicrobial defenses using a specialized protein secretion system. This system, known as the Salmonella pathogenicity island 2 (SPI2) type III secretion system, injects proteins from the bacteria-containing phagosome into the cytosol of the infected cell. These proteins disrupt normal vesicular trafficking and prevent the fusion of the phagosome with the degradative lysosomes where the bacteria would...
