Fig 1. Myriocin and Fumonisin B1 block sphingolipid biosynthesis in RAW macrophages and dendritic cell lines.

(A) Schematic representation of the sphingolipid biosynthetic pathway in mammalian cells. Myriocin, a serine palmitoyltransferase (SPT) inhibitor, and Fumonisin B1 (FB1), a ceramide synthase (CS) inhibitor, block sphingolipid biosynthesis (boxed). The salvage pathway is shown in broken arrows. (B) Myriocin- or FB1-treated cells were labeled with the sphingomyelin precursor N-methyl-[¹⁴C]-choline, and total lipids were extracted and analyzed by TLC and autoradiography. (C) Quantification of the [¹⁴C]-SM and [¹⁴C]-PC signals from [¹⁴C]-choline labeling experiment in B. Error bars display SD of three independent experiments. Unpaired t-test was used to analyze the significance of the observed differences. ** p < 0.001.