TABLE 1.
Proteins which are secreted via the type III secretion pathway
| Organism | Secreted proteina (reference) | Biochemical activity; interaction with host or other proteins | Effect on host cell; function | Remarks |
|---|---|---|---|---|
| Yersinia spp. | YopE, 219 (131) | Cytotoxic, F-actin disruption | Translocated | |
| YopH, 468 (59, 305) | PTPase dephosphorylates paxillin, FAK, p130cas | Inhibition of phagocytosis | Translocated | |
| YpkA, 732 (149) | Protein serine/threonine kinase | Translocated | ||
| YopM, 367 (56, 269) | Binds to thrombin | Translocated | ||
| YopJ/P, 264/288 (150, 313) | Induction of apoptosis in macrophages | Similar to plant pathogen AvrX and AvrA from S. typhimurium | ||
| YopR, 165 (14, 307) | ||||
| YopB, 401 (173) | Pore-forming translocase | Translocation | ||
| YopD, 306 (173) | Translocation | |||
| YopK, 182 (206) | Modulation of translocation efficiency | |||
| YopN, 293 (129, 454) | Putative surface sensor, regulation of secretion | |||
| LcrV, 326 (41, 343, 359) | Suppression of immune response | Also regulatory function | ||
| LcrG, 95 (41, 359) | Regulation of secretion | |||
| LcrQ/YscM1/YscM2, 115 (307, 370, 422) | Involved in feedback transcriptional regulation | |||
| P. aeruginosa | ExoS, 453 (253) | ADP-ribosyltransferase | Cytotoxic, F-actin disruption | |
| ExoT, 457 | ADP-ribosyltransferase | |||
| ExoU, 687 (120) | Cytotoxic | |||
| PcrV, 294 (493) | ||||
| PopB, 392 (493) | Translocation (?) | |||
| PopD, 295 (493) | Translocation (?) | |||
| PopN, 288 (493) | Regulation of secretion (?) | |||
| S. flexneri | IpaB, 580 (450) | Binds to α5β1 integrin and to ICE protease | Induction of membrane ruffling, phagosomal lysis, induction of apoptosis | Additional function in regulation of secretion |
| IpaC, 382 (450) | Binds to α5β1 integrin | Induction of membrane ruffling, phagosomal lysis | ||
| IpaD, 332 (450) | Binds to α5β1 integrin | Cell invasion, phagosomal lysis | Regulation of secretion | |
| IpaA, 633 (451) | Binds to vinculin | Modulation of cell invasion | ||
| VirA, 400 (443) | Intercellular spread | |||
| S. typhimurium SPI-1 | AvrA, 302 (183) | |||
| Sip/SspB, 593 (234) | Cell invasion, induction of apoptosis | Translocation | ||
| Sip/SspC, 409 (216, 234) | Cell invasion, induction of apoptosis | Translocation | ||
| Sip/SspD, 338 (216, 233) | Cell invasion, induction of apoptosis | Translocation, regulation of secretion (?) | ||
| Sip/SspA, 684 (233) | ||||
| SopB, 561 (151) | Involved in intestinal transepithelial signalling, translocated | |||
| SopE, 240 (485) | Translocated | |||
| SptP, 544 (235) | PTPase | |||
| EPEC | EspA, 198 (242) | A/E lesion formation | ||
| EspB, 321 (104) | A/E lesion formation | |||
| EspC, 381 (259) | A/E lesion formation | |||
| Tir, 549 (239) | Binds to EPEC intimin | Receptor for EPEC attachment | Inserted in eukaryotic cell membrane, modified by tyrosine phosphorylation | |
| P. syringae | AvrPtob, 164 (390) | Binds to Pto kinase | Elicitation of HR | Host range determination, translocated (?) |
| HrpA, 113 (357) | Structural component of Hrp pilus | |||
| HrpZ, 341 (188) | Elicitation of HR | |||
| E. amylovora | HrpN, 385 (472) | Elicitation of HR | ||
| R. solanacearum | PopA1, 344 (26) | Elicitation of HR |
a
The size of the protein in amino acids is shown after the protein name. See text for further details and references.
b
Many more Avr proteins from various plant pathogens (recently summarized in reference 455) have been cloned and might be secreted and translocated via type III secretion pathways.