Stable overexpression of wild-type hamster LCB1 and its C133Y or C133W mutant in CHO-K1 cells. (a) Western blotting for the LCB1 subunit. Each lane was loaded with 20 μg protein of cell lysate. (b) SPT activity in cell lysate. Data shown are from triplicate experiments. (c) Metabolic labeling of lipids in intact cells with L-[14C(U)]serine. Radioactivity of each lipid type was determined and normalized for protein. Data are shown as the percentage of the mean values obtained in CHO-K1 cells from four experiments. *P < 0.01 vs. the CHO-K1 levels.