Invasin

Invasin refers to a bacterial surface protein that promotes the entry of the bacteria into non-phagocytic host cells. Invasins function by binding to specific host cell receptors, triggering signal transduction pathways that ultimately result in the rearrangement of the host cell cytoskeleton. This rearrangement leads to the engulfment of the bacteria via receptor-mediated endocytosis.

The most well-characterized invasin is produced by Yersinia bacteria, such as Yersinia pseudotuberculosis and Yersinia enterocolitica. This Yersinia invasin binds to beta1 integrin receptors on the surface of host cells. Other bacteria utilize different invasins that target other host cell receptors.

The ability of bacteria to produce invasins is a crucial virulence factor, enabling them to colonize and establish infection within the host. By gaining entry into host cells, bacteria can evade the host's immune defenses and access nutrients, contributing to the progression of disease. Different bacterial species encode a variety of invasins, each optimized for interacting with specific host cell types and receptors. The study of invasins is important for understanding bacterial pathogenesis and developing strategies to prevent or treat bacterial infections.