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PMID:24072713
| Citation |
'Bonsor, DA, Weiss, E, Iosub-Amir, A, Reingewertz, TH, Chen, TW, Haas, R, Friedler, A, Fischer, W and Sundberg, EJ (2013) Characterization of the translocation-competent complex between the Helicobacter pylori oncogenic protein CagA and the accessory protein CagF. J. Biol. Chem. ' |
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| Abstract |
CagA is a virulence factor that Helicobacter pylori inject into gastric epithelial cells through a Type IV Secretion System (T4SS) where it can cause gastric adenocarcinoma. Translocation is dependent on the presence of secretion signals found in both the N- and C-terminal domains of CagA and an interaction with the accessory protein CagF. However, the molecular basis of this essential protein-protein interaction is not fully understood. Herein we report, using isothermal titration calorimetry (ITC), that CagA forms a 1:1 complex with a monomer of CagF with nM affinity. Peptide arrays and ITC both show that CagF binds to all five domains of CagA, each with μ affinity. More specifically, a coiled-coil domain and a C-terminal helix within CagF contacts domains II-III and domain IV of CagA, respectively. In vivo complementation assays of H. pylori with a double mutant L36A/I39A in the coiled-coil region of CagF showed a severe weakening of the CagA-CagF interaction to such an extent that it was nearly undetectable. However, it had no apparent effect on CagA translocation. Deletion of the C-terminal helix of CagF also weakened the interaction with CagA but likewise had no effect on translocation. These results indicate that the CagA-CagF interface is distributed broadly across the molecular surfaces of these two proteins to provide maximal protection of the highly labile effector protein, CagA. |
| Links |
PubMed Online version:10.1074/jbc.M113.507657 |
| Keywords |
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| edit table |
Significance
Annotations
| Gene product | Qualifier | GO Term | Evidence Code | with/from | Aspect | Extension | Notes | Status |
|---|---|---|---|---|---|---|---|---|
| GO:0072321: chaperone-mediated protein transport |
ECO:0000314: |
P |
Figure 1 shows CagF interaction with CagA using calorimetric analysis; CagF chaperone mediates CagA translocation into gastric epithelial cells. |
complete | ||||
See also
References
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