Yersiniae Virulence Factors: Type III Secretion System

Yersiniae Virulence Factors: Type III Secretion System

Several Gram-negative pathogenic bacteria have evolved a complex protein secretion system termed the Type Three Secretion System (TTSS) to deliver bacterial effector proteins into host cells that then modulate host cellular functions. These bacterial devices are evolutionarily related to the flagellar apparatus. Although the TTSSs are substantially conserved among different species, the effector molecules they deliver are species unique. There exist three human pathogenic Yersiniae. Yersinia enterocoliticaand Yersinia pseudotuberculosis cause self-limiting gastro-enteric diseases and infect mesenteric lymph nodes, while Yersinia pestis is transmitted by fleas and can be aerosolized, causing the lethal disease known as plague (also know as Black Death). The TTSS is composed of over 20 proteins making up the injectisome (inserted directly into the host-cell), in addition to translocator, regulator, and modulator proteins, as well as chaperones for several effector proteins. Today, plague is still a health concern due to the ability of Y. pestis to be aerosolized. No effective vaccines are currently available to the public. However, research is currently being conducted to create a vaccine that can be widely used.