The Helicobacter pylori Cag Type IV Secretion System. Issue 8 (August 2020) - Cover, Timothy L.
Abstract : Colonization of the human stomach with Helicobacter pylori strains containing the cag pathogenicity island is a risk factor for development of gastric cancer. The cag pathogenicity island contains genes encoding a secreted effector protein (CagA) and components of a type IV secretion system (Cag T4SS). The molecular architecture of the H. pylori Cag T4SS is substantially more complex than that of prototype T4SSs in other bacterial species. In this review, we discuss recent discoveries pertaining to the structure and function of the Cag T4SS and its role in gastric cancer pathogenesis. Highlights: The Cag T4SS has a key role in the pathogenesis of H. pylori -associated gastric cancer. Recent advances in molecular imaging have facilitated investigation of the H. pylori Cag T4SS structure. The H. pylori Cag T4SS contains multiple components unrelated to components of T4SSs in other bacterial species, and the molecular architecture of the H. pylori Cag T4SS is substantially more complex than that of prototype T4SSs. T4SSs are a heterogeneous group of secretion systems with diverse functions. Despite a low level of sequence relatedness among corresponding components of T4SSs from different bacterial species, there are shared structural features among all T4SSs analyzed thus far.