FIG. 3.
The constitutively active IκBβ is unable to completely displace IκBα bound to RelA. Control (A) and transgenic (B) thymocytes labeled with [35S]methionine for 4 h were treated with PMA-PHA for the indicated periods. The cell extracts were first immunoprecipitated with anti-RelA antibodies, and the RelA-containing immune complexes were denatured and sequentially precipitated with anti-RelA, anti-IκBα, or anti-IκBβ antibodies. The supernatants of the first precipitations were sequentially precipitated with anti-IκBα and anti-IκBβ antibodies.