Förster resonance energy transfer (FRET) provides a powerful tool for monitoring intermolecular interactions and a sensitive technique for studying Å-level protein conformational changes. One system that has particularly benefited from the sensitivity and diversity of FRET measurements is the maturation of the Shigella type III secretion apparatus (T3SA) needle tip complex. The Shigella T3SA de...

Shigellosis is an important disease in the developing world, where about 90 million people become infected with Shigella spp. each year. We previously demonstrated that the type three secretion apparatus (T3SA) proteins IpaB and IpaD are protective antigens in the mouse lethal pulmonary model. In order to simplify vaccine formulation and process development, we have evaluated a vaccine design t...

Pseudomonas aeruginosa harbors a type III secretion system that translocates antihost effectors into an infected eukaryotic cell. PcrH is a key component of type III secretion in this essential virulence strategy. In the absence of PcrH, P. aeruginosa is translocation deficient because of a specific reduction in presecretory stability and subsequent secretion of PopB and PopD, 2 proteins essent...

Activation of the type III secretion apparatus (T3SA) of Shigella flexneri, upon contact of the bacteria with host cells, and its deregulation, as in ipaB mutants, specifically increases transcription of a set of effector-encoding genes controlled by MxiE, an activator of the AraC family, and IpgC, the chaperone of the IpaB and IpaC translocators. Thirteen genes carried by the virulence plasmid...

Acknowledgements The authors contributed equally. We gratefully acknowledge financial assistance from the EU Marie-Curie Intra European Fellowship Scheme (grant nr MEIF-CT-2005-011465), the IPGC (Innovation and Productivity Grand Challenge), the Mack Center for Technological Innovation at Wharton School, and the Stern School of Business (NYU). We are especially grateful to Paul Allison and Dean...

Shigella spp. are causative agents of bacillary dysentery, a human illness with high global morbidity levels, particularly among elderly and infant populations. Shigella infects via the fecal-oral route, and its virulence is dependent upon a type III secretion system (T3SS). Two components of the exposed needle tip complex of the Shigella T3SS, invasion plasmid antigen D (IpaD) and IpaB, have b...

Proteins directly involved in entry and dissemination of Shigella flexneri into epithelial cells are encoded by a virulence plasmid of 200 kb. A 30-kb region (designated the entry region) of this plasmid encodes components of a type III secretion (TTS) apparatus, substrates of this apparatus and their dedicated chaperones. During growth of bacteria in broth, expression of these genes is induced...