Figure 5.

Ceramide-enhanced phosphorylation of S6K is dependent on LAPTM4B and 4F2hc. (A) A431 cells were treated with siRNAs against LAPTM4B- and/or 4F2hc, (B) ASAH1- or/and LAPTM4B, and (C) SMPD1- or/and LAPTM4B, respectively. Cells were starved (1 h with EBSS), and S6K/pS6K expression was assessed by Western blotting upon refeeding with stimulation medium for the indicated times. Left panels, show representative experiments; right panels, quantifications of n ≥ 3 experiments, mean ± SEM. Differences are significant for p* < 0.05 compared to the control.