Table 1.
Organism/plasmid | Name | Function | Known substrates | Main new results presented1 |
---|---|---|---|---|
a) T4S systems involved in animal cell infection (chromosomally encoded) | ||||
Anaplasma spp | VirB/D4 | Infection of macrophages | AnkA, Ats-1 | New substrate locating in mitochondria |
Immunogenicity of T4S proteins | ||||
Bartonella henselae | Trw | Adhesion to erythrocytes | None detected | Role in host specificity |
VirB/D4 | Infection of endothelial cells | BepA-G | Role in host adaptation | |
Brucella spp. | VirB | Infection of macrophages | VceA, VceC | First T4S substrates detected |
VirB2 interaction with host cell surface | ||||
Metabolic regulation of virB expression | ||||
Coxiella burnetii | Dot/Icm | Infection of phagocytes | Multiple effectors | Novel substrates identified |
Ehrlichia chaffensis | VirB/D4 | Infection of macrophages | None | Regulation of expression, Vir subassemblies |
Helicobacter pylori | Cag | Infection of gastric cells | CagA, peptidoglycan | T4S contact with β1 integrins |
Legionella pneumophila | Dot/Icm | Infection of macrophages | DNA, multiple effectors | Polar secretion of substrates |
Temporal/spatial distribution of effectors | ||||
b) T4S systems involved in DNA transfer (present in plasmids or genomic islands) | ||||
Agrobacterium tumefaciens pTi | VirB/D4 | T-DNA transfer to plants | T-DNA, VirD2, VirD5, VirE2, VirE3, VirF | VirB10 structure/function analysis |
T4S helical localization pattern | ||||
Escherichia coli pKM101 | Tra | Conjugative plasmid transfer | DNA, TraI2 | 3D structure of core complex |
Escherichia coli R1 | Tra | Conjugative plasmid transfer | DNA, TraI2 | Helicase loading at relaxosome |
Escherichia coli R388 | Trw | Conjugative plasmid transfer | DNA, TrwC | Transfer through Bartonella T4SS |
Haemophilus influenzae GI | Tfc | GI horizontal transfer | DNA | New family of T4S systems |
Neisseria gonorrhoeae GI | Tra | DNA secretion and transfer | DNA, TraI2 | Search for oriT; role of pilin |
Streptococcus pIP501 | Tra | Conjugative plasmid transfer | DNA, TraA2 | Protein-protein interactions |
See text for details and labs reporting the results.
Transport of the relaxase protein is assumed based on homology with other DNA transfer systems