Structure of a molecular machine in a bacterium that contributes to gastric cancer

What is it about?

The bacterium Helicobacter pylori lives in the human stomach, and the presence of these bacteria increases the risk of stomach cancer. This paper analyzes a secretion system used by Helicobacter pylori to inject a bacterial protein into stomach cells. A microscopic imaging method called cryo-electron microscopy allowed the shape and structure of this secretion to be visualized.

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Why is it important?

This paper provides the first high-resolution views of the Helicobacter pylori Cag type IV secretion system. The H. pylori system is considerably larger and more complex than related type IV secretion systems found in several other bacterial species. The findings in this paper open the door for future research to understand how the H. pylori secretion system works and to understand its relationships to type IV secretion systems in other bacterial species.