Degradation rates of CD40 mutants. The graphs represent the decay of control (C) and CD40 mutants in a time-course treatment of BLCLs with CHX. The protein expression values were determined by densitometric analysis of anti-CD40 immunoblots and were expressed as percentages of the CD40 expression in untreated cells (0 hour). In the graph representing P4, the empty symbols show CD40 decay in the presence of both CHX and MG132. Each cell line was analyzed in at least 2 independent experiments, and data are given as means ± SD.