Table 2.
Putative T3SS3 effectors, translocons, and chaperones. The ‘Average identity’ column shows amino acid conservation rates in the Vib-T3SS3 strains. The letters in the ‘Strains’ column indicate the presence of a homolog (A: V. aquimaris strain THAF100; C: V. coralliilyticus OCN008; P: V. pectenicida 99-46-Y; and T: Vibrio sp. THAF191c).
| Protein Names | T3SS Family | Average Identity % | Strains | Biochemical and Cellular Functions |
|---|---|---|---|---|
| SseF | Ssa-Esc | 29.5 | A, C, P | Core effector in all pathogenic Salmonella serovars, tethering Salmonella-containing vacuoles (SCVs) to the Golgi network. SseF functions with another core effector, SseG protein [3]. |
| SspH2 | Ssa-Esc | 32.5 | T | Effector (E3 ubiquitin ligase) in pathogenic Salmonella, interfering with host immune signaling. SspH2 is associated with SspH1 and SlrP, which also show E3 ligase activity [3]. |
| SseJ | Ssa-Esc | 33.4 | A, P | Effector (acytransferase) in pathogenic Salmonella, preventing collapse of microtubules to provide a solid network around SCVs [3,30]. |
| PipB | Ssa-Esc | 32.4 | A, C, P, T | Core effector of unknown function in all pathogenic Salmonella serovars, localizing to SCVs and SIFs. Its associated protein PipB2 controls the kinesin-1 motor protein of host cells [3]. |
| SopD2 | Ssa-Esc | 33.3 | A, C | Effector that prevents from directing SCVs into late endosomes and lysosomes [3,30] |
| SopD | Ssa-Esc Inv/Mxi-Spa |
18.9 | A | Effector that promotes plasma membrane scission and the generation of SCVs [30] |
| CesD | Ssa-Esc | 39.5 25.4 |
A, C, P, T | T3SS chaperone in enteropathogenic E. coli strains for more efficient secretion [31,32] |
| CesT | C, T | |||
| SseB | Ssa-Esc | 37.7 30.3 28.4 |
A, C, P, T | Translocon proteins in Salmonella strains to transfer T3SS effectors [33] |
| SseC | ||||
| SseD | ||||
| BopA/IcsB | Inv/Mxi-Spa | 23.4 | C, T | Effector in Shigella or Burkholderia strains helping to evade the host autophagy defense system [34] |
| BopC | Inv/Mxi-Spa | 44.5 | A, P | Effector in Bordetella strains contributing to the necrotic cell death of mammalian host cells [35] |
| ExoY | Ysc | 31.2 | A, P | Common effector (adenylate cyclase) in clinically isolated Pseudomonas aeruginosa, delaying the inflammatory pathways in mammalian host cells [36] |
| Scc2 | Chlamydiales | 27.5 | C | T3SS chaperone specific to Chlamydia species and is similar to SycD of Yersinia, SicA of Salmonella, and IpgC of Shigella [37] |