UC San Diego

Bacterial pathogens have evolved various strategies to aid in bacterial survival and dissemination, despite the presence of multiple host defense mechanisms. One tactic that is employed by bacterial pathogens is the secretion of effector proteins across phospholipid membranes through specialized secretion systems. Many enteric pathogens secrete effector proteins using the Type III secretion system (T3SS) to manipulate various host cellular processes such as evading the host immune response, rearranging the host cell morphology, disrupting tight junctions, regulating cell death pathways, and modifying membrane and vesicular trafficking. Some T3SS effector proteins contain a conserved WxxxE motif with GEF-like activity that is important for their function. However, the presence of this WxxxE motif is not limited to T3SS effectors, it is also found in T2SS and T4SS virulence factors belonging to non-enteric and plant pathogens. In addition to this, in-silico data analysis revealed the presence of a conserved WxxxE motif in the TIR domains of both bacteria and eukaryotic proteins. While these virulence factors share a common WxxxE motif, their functions can vary depending on the pathogen and its mode of infection. Yet, little is known about the role of WxxxE-containing effector proteins on the bacterial pathogenesis. Hence, further functional studies will help understand the function of the WxxxE motif in these pathogenic bacteria.