FIG. 4.
CBP interacts with CIITA at its N terminus. (A) COS7 cells (9 × 105) were cotransfected with 3 μg of FlagCIITA or FlagCIITA(1-58) or FlagCIITA(1-94) or its corresponding control vector, pcDNA3, and 3 μg of CMV5-CBP or its empty vector, CMV5, as indicated. Cells were lysed with 1.5 ml of RIPA buffer 36 h after transfection, and 25 μl of the samples was subjected to SDS–10% polyacrylamide gel electrophoresis resolution. The expression of CBP was analyzed by immunoblotting (IB) using the rabbit anti-CBP antibody. (B) The cell lysate described above was immunoprecipitated (IP) with anti-Flag M2-agarose at 4°C overnight. The association of CBP with wild-type FlagCIITA (lane 2) and mutant FlagCIITA(1-94) was revealed by immunoblotting using the rabbit anti-CBP antibody.