FIGURE 3.

De novo sphingolipid synthesis is reduced in S1P lyase-deficient neurons. Cultured wild type (+/+) and S1P lyase-deficient (−/−) neurons were labeled with [¹⁴C]serine (2 μCi/ml) for 24 h. Then, cells were harvested, and lipids were extracted, isolated, separated by TLC in (A) chloroform/methanol/0.22% CaCl₂ (60:35:8) or (B) chloroform/methanol/acetic acid (190:9:1), and (C) quantified as described under “Experimental Procedures.” x, unknown compound; SM, sphingomyelin; Cer, ceramide; SL, sphingolipids. Data are averages of triplicate determination and given relative to wild type controls.