Transporting Botulism Toxin Across The Intestinal Wall

The neurotoxin that causes botulism moves from the gut into the bloodstream with help from a bacterial protein complex, reports a group led by Rongsheng Jin of the University of California, Irvine (Science 2014, DOI: 10.1126/science.1253823). The complex disrupts adhesion of intestinal cells, allowing the toxin to slip between them and through the intestinal wall. Understanding how botulinum neurotoxin (BoNT) makes its way from gut to blood to motor neurons—where it inhibits neurotransmitter release—could lead to ways to prevent botulism. Researchers already knew that BoNT binds to an assembly of 12 bacterial proteins called hemagglutinins that interact with intestinal epithelial cells. In the new work, Jin and colleagues found that the hemagglutinins bind to sugars and adhesion proteins on intestinal cell surfaces and disrupt adhesion protein interactions that hold the cells together. That opens routes for BoNT to squeeze between cells to get into the bloodstream.