FIGURE 4.

ACER3 knockdown by RNAi increases ULC ceramides in cells. A–D, HeLa cells at a 50% confluence were transfected with 5 nm siCON, siACER3-1, or siACER3-2, or with buffer only (no siRNA). At 48 h post-siRNA transfection, cells were harvested for qPCR analysis of ACER3 mRNA levels (A), alkaline ceramidase activity assays (B), or ESI/MS/MS analyses of sphingolipids (C and D). Data represent mean values ± S.D. of three independent experiments. *, p < 0.05 versus the control siCON or no siRNA. MNE, mean normalized expression.