Figure 1.

Alteration of the SM-Cer pathway induced by TNF in human fibroblasts expressing a truncated FAN. Human fibroblasts transfected with empty vector (pcDNA3) or a plasmid carrying a truncated FAN (ΔFAN) were labeled for 48 hours with [³H]choline. After a 2-hour chase, cells were incubated at 37°C in the presence of 50 ng/ml human TNF (a and b) or with 1 μM daunorubicin (DNR; c). At the indicated time points, incubations were stopped, and SM levels (a and c) were determined. Cer levels (b) were determined using diacylglycerol kinase. SM and Cer levels are expressed as percentage of the value observed before treatment. All values correspond to the mean ± SE of three independent experiments. Inset: Expression of CD120a in fibroblasts transfected with the empty vector (P) or a vector encoding the mutated FAN (ΔF).