Type III Secretion Systems and Disease

Abstract

SUMMARY Type III secretion systems (T3SSs) are complex bacterial structures that provide gram-negative pathogens with a unique virulence mechanism enabling them to inject bacterial effector proteins directly into the host cell cytoplasm, bypassing the extracellular milieu. Although the effector proteins vary among different T3SS pathogens, common pathogenic mechanisms emerge, including interference with the host cell cytoskeleton to promote attachment and invasion, interference with cellular trafficking processes, cytotoxicity and barrier dysfunction, and immune system subversion. The activity of the T3SSs correlates closely with infection progression and outcome, both in animal models and in human infection. Therefore, to facilitate patient care and improve outcomes, it is important to understand the T3SS-mediated virulence processes and to target T3SSs in therapeutic and prophylactic development efforts.

XopD SUMO Protease Affects Host Transcription, Promotes Pathogen Growth, and Delays Symptom Development inXanthomonas-Infected Tomato Leaves

“…The suppression of eukaryotic immune responses by T3S effectors is a shared theme of many pathogens (Abramovitch et al, 2006a;Coburn et al, 2007). However, little is known about other host processes affected by these proteins during host-microbe interactions.…”

The type III secretion system of Vibrio alginolyticus induces rapid apoptosis, cell rounding and osmotic lysis of fish cells

“…Many of these effectors are virulence factors that can trigger host-cell death and manipulate the innate immune system (Coburn et al, 2007). Numerous other pathogenic bacteria, such as Yersinia spp., Pseudomonas aeruginosa, Salmonella spp.…”

In Vitro and In Vivo Model Systems for Studying Enteropathogenic Escherichia coli Infections

“…In addition to Tir, the T3SS translocates an assortment of effector proteins into host cells, which subvert cellular processes to promote A/E pathogen infection (Kenny 2002;Dean et al 2005;. To date, several LEE-encoded effectors, as well as a number of non-LEE (Nle)-encoded effectors , have been identified in the genomes of EPEC and EHEC (Tobe et al 2006;Coburn et al 2007;Iguchi et al 2009). …”

“…1) (Coburn et al 2007). The seven LEE-encoded type III secreted (T3S) effectors as well as some of the Nle effectors are well conserved across A/E pathogen species, whereas the number and type of other Nle effectors varies significantly (Dean and Kenny 2009).…”