FIG. 4.
Stat1 inhibits TRADD interaction with RIP and TRAF2 but not with FADD. (A) FADD, RIP, and TRAF2 were immunoprecipitated (IP) from whole-cell lysates prepared from 2fTGH, U3A, and U3A-S1 cells treated or not with TNF-α. FADD, RIP, and TRAF2 precipitates were then subjected to TRADD immunoblot analysis. The levels of FADD, RIP, TRAF2, and TRADD in these cell lysates were examined by blotting with their specific antibodies as indicated. (B) Whole-cell lysates prepared from TNF-α-treated HeLa cells were incubated with purified GST-TRADD and different amounts of recombinant His6-Stat1 protein (0.1 or 0.3 μg). GST-TRADD precipitates were subjected to anti-RIP, anti-TRAF2, and anti-FADD antibody immunoblot analysis.