Recent structural advances towards understanding of the bacterial type III secretion injectisome

The bacterial injectisome is a structurally conserved, syringe-shaped nanoma-chine that spans the Gram-negative envelope and forms a continuous channel for type III secretion of protein effectors. The injectisome, and the host-modulating effectors it secretes, are essential for the pathogenesis of several Gram-negative bacterial species, and it is a key virulence factor associated with the progression of many clinical and community-based infectious diseases. The molecular struc-ture of the injectisome has been the focus of intense research efforts over the past 30 years, and during this time significant progress has been made in determining the molecular structures of many components. In this review we present major advances in our structural and mechanistic understanding of the injectisome, as facilitated by cryoelectron microscopy approaches.

Automated summary

The bacterial injectisome is a crucial nanomachine that plays a key role in the pathogenesis of Gram-negative bacteria by injecting protein effectors into host cells. Cryoelectron microscopy has greatly contributed to our understanding of the molecular structure and mechanism of the injectisome over the past 30 years.