CPE synthase, SMS, PE-PLC, and PC-PLC activity assays, using SMSr-flag immunoprecipitate and exogenous substrates. Cos7 cells were transfected with SMSr-flag expression or empty vector. SMSr-flag (SMSr-F) was immunoprecipitated and the precipitate was used to perform CPE synthase, SMS, PE-PLC, and PC-PLC activity assays, as described in “Materials and Methods”. The products were separated by thin layer chromatography. (A) CPE synthase activity assay, using NBD-Cer and PE as two substrates. (B) SMS activity assay, using NBD-Cer and PC as two substrates. (C) PE-PLC activity assay, using NBD-PE as a substrate. (D) PC-PLC activity assay, using NBD-PC as a substrate. (E) PC-PLC activity assay, using 14C-PC as a substrate. +, Bacterial PLC was used as a positive control. The development solvent for (A) and (B) was Chloroform:Methanol:NH4OH: 14:6:1 (v/v/v); The development solvent for (C)-(E) was Chloroform:Methanol: 15:1 (v/v). The results were the representative of three independent experiments.