Figure 3.

Schematic drawing of the Shigella Type III Secretion System (Roerich-Doenitz, 2013). The architecture of Shigella T3SS is based on the virulence plasmid mxi-spa locus (Figure 2), which encodes proteins that produce the T3SS apparatus, a structure composed of a 60 nm hollow extracellular needle, a transmembrane domain, and a cytoplasmic bulb (Blocker et al., 1999).