TABLE 1.
In vivo phosphorylation targets IRF3 from SV- and mock-infected cells
FLAG-tagged IRF3 was isolated from either SV- or mock-infected cells and subjected to in-gel digestion and MS analysis as described under “Experimental Procedures.” The 2nd column (PO4) indicates the number of phosphates present on each peptide. The “Sample” column indicates different molecular weights of IRF3-containing complexes that were isolated after BN-PAGE. NS1 and SV1 correspond to monomeric IRF3. NS2–4 and SV2–4 represent IRF3-containing complexes of higher molecular weights.
| IRF3 peptide | No. of PO4 | Amino acid | Sample |
|---|---|---|---|
| BN-PAGE | |||
| 173–193 | 1 | Mix 173 and 175a | NS1 |
| 173–193 | 1 | Mix 173 and 175a | NS2 |
| 173–193 | 1 | Mix 173 and 175a | NS3 |
| 381–409 | 1 | Ser385 or Ser386 | |
| 173–193 | 1 | Mix 173 and 175a | NS4 |
| 381–409 | 1 | Ser385 or Ser386 | |
| 173–193 | 1 | Mix 173 and 175a | SV1 |
| 381–409 | 1 | Ser386 | |
| 381–409 | 2 | ||
| 173–193 | 1 | Mix 173 and 175a | SV2 |
| 381–409 | 1 | Ser386 | |
| 381–409 | 1 | Ser386 and Thr390 | |
| 173–193 | 1 | Mix 173 and 175a | SV3 |
| 381–409 | 1 | Ser386 | |
| 381–409 | 2 | Ser386 and Thr390 | |
| 173–193 | 1 | Mix 173 and 175a | SV4 |
| 381–409 | 1 | Ser386 | |
| 381–409 | 2 | Ser386 and Thr390 | |
| SDS-PAGE | |||
| 173–193 | 1 | Mix 173 and 175a | NS |
| 381–409 | 1 | Ser385, Ser386, or (Thr390) | |
| 173–193 | 1 | Mix 173 and 175a | SV |
| 381–409 | 1 | Ser385 or Ser386 | |
| 381–409 | 2 | (Ser386 and Thr390), (Thr390 and Ser396), (Ser385 and Ser386) | |
a Either of the two phosphorylations (Ser173 or Ser175) is present, but the position could not be unequivocally determined.