Crk gets hijacked

The ulcer-inducing bacterium Helicobacter pylori busts through the cells that line the stomach by hijacking a host protein, suggest Suzuki and colleagues on page 1235. The co-opted protein turns on multiple signaling pathways in gastric cells that cause the normally adhesive cells to pull apart from their neighbors. Roughly half of all people worldwide have H. pylori living in their stomachs. Most people host the infection without consequence but, in some, H. pylori infection triggers peptic ulcers and gastric cancer. H. pylori encodes a set of proteins that allows it to adhere to and thrive in the stomach and to avoid immune attack. One of these proteins—CagA (cytotoxin-associated antigen-A)—helps ward off immune cells but also disrupts the epithelial cells that line the stomach. Many studies have investigated how CagA, which is injected into gastric epithelial cells through a specialized bacterial Gassy degeneration