Table 1.
List of the α-helical T3S effectors discussed in this paper.
| General Function | T3SEs | Specific Host Target |
|---|---|---|
| Gatekeepers |
Chlamydia pneumoniae CopN Shigella MxiC, Yersinia YopN/TyeA (heterodimer) |
Scc3, tubulin |
| Membrane docking | Pseudomonas aeruginosa ExoU | membrane |
| GAP activity |
Salmonella SptP, P. aeruginosa ExoS/T E. coli EspG, EspG2, Shigella flexneri VirA, Citrobacter rodentium EspI |
Rac1 Rab |
| GEF activity |
Salmonella SPI-1 SopE, SopE2, E. coli MAP Burkholderia BopE, Salmonella SPI-2 SifA, Shigella IpgB1, IpgB2 |
Cdc42 |
| GDI activity | Yersinia YopO/YpkA | Rac1 |
| PTM activity |
Vibrio parahaemolyticus VopS (AMPylation) P. syringae AvrB E. coli NleB, Salmonella Ssek3, Ssek1 (Arg-GlcNAcylation) |
Rho, Rac, Cdc42 RIN4 DD proteins |
| Transcription activation | Xanthomonas AvrBs3, PthXo1, Hax3, Burkholderia rhizoxinica Bud | DNA |
| Host immunity activation in resistant plants |
Pseudomonas syringae AvrRps4 (suppress immunity in susceptible plants, chloroplast localization is required) Pseudomonas AvrPto, AvrPtoB Xanthomonas AvrRxo1-ORF1 (T4-polynucleotide kinase) Xanthomonas campestris XopQ (suppress immunity in susceptible plants) |
Pto * (Api) Rxo1 * Roq1 * (14–3-3) |
| Zinc metalloproteases |
EPEC NleC, EHEC NleD, Salmonella enterica GtgA, GogA, PipA Ralstonia solanacearum RipAX2 |
NF-κB |
| Kinases | EPEC NleH1, EHEC NleH2, Shigella OspG | NF-κB |
| Novel E3 Ligases | Shigella IpaH, Salmonella SspH | Ub network |
* Plant R (resistance) proteins in resistant plants. Abbreviations used in this table and throughout the paper: Api, AvrPto interacting; ART, ADP-Ribosyltransferase; Avr, Avirulence; CBD, Chaperone Binding Domain; DD, Death Domain; EHEC, Enterohemorrhagic Escherichia coli; EPEC, Enteropathogenic E. coli; GAP, GTPase Activating Protein; GEF, Guanine nucleotide Exchange Factor; GDI, Guanosine nucleotide Dissociation Inhibitor; GlcNAc, N-acetylglucosamine; HR, Hypersensitive Response; LRR, Leucine-Rich Repeat; MLD, Membrane Localization Domain; NEL, Novel E3 Ligase; NF-κB, Nuclear Factor Kappa B; ORF, Open Reading Frame; PDB, Protein Data Bank; PMF, Proton Motive Force; PTM, Post-Translational Modification; PTPase, Protein Tyrosinephosphatase; R protein, Resistance protein; SPI, Salmonella Pathogenicity Island; SS, Secretion Sequence; TALE, Transcription Activator-Like Effector; TPR, Tetratrico-Peptide Repeats; T3SS, Type 3 Secretion System; Ub, Ubiquitin.