Bacterial effector protein

For instance, in the causative agent of plague (Yersinia pestis), the loss of the T3SS is sufficient to render the bacteria completely avirulent, even when they are directly introduced into the bloodstream.

[3] Gram negative microbes are also suspected to deploy bacterial outer membrane vesicles to translocate effector proteins and virulence factors via a membrane vesicle trafficking secretory pathway, in order to modify their environment or attack/invade target cells, for example, at the host-pathogen interface.

For instance, Tobe et al. (2006) predicted more than 60 effectors for pathogenic E. coli but could only show for 39 that they are secreted into human Caco-2 cells.

The T3SS effectors of pathogenic E. coli, Shigella, Salmonella, and Yersinia regulate actin dynamics to facilitate their own attachment or invasion, subvert endocytic trafficking, block phagocytosis, modulate apoptotic pathways, and manipulate innate immunity as well as host responses.

Several bacteria, including Salmonella and Shigella, enter the cell and survive intracellularly by manipulating the endocytic pathway.

Once internalized by host cells Salmonella subverts the endolysosome trafficking pathway to create a Salmonella-containing vacuole (SCV), which is essential for its intracellular survival.

As the SCVs mature they travel to the microtubule organizing center (MTOC), a perinuclear region adjacent to the Golgi, where they produce Salmonella induced filaments (Sifs) dependent on the T3SS effectors SseF and SseG.

[19] By contrast, internalized Shigella avoids the endolysosome system by rapidly lysing its vacuole through the action of the T3SS effectors IpaB and C although the details of this process are poorly understood.

This leads to expression of cytokines, immunomodulating agents, such as interleukins and interferons which regulate immune response to infection and inflammation.

[39] YopJ family members are acetyltransferases that modify lysine, serine or threonine residues with an acetyl group, leading to protein aggregation,[40] blockage of phosphorylation[41] or inhibition of ATP binding.