FIGURE 1.

SMS expression and activity in the CD4⁺ T cell line. A, mRNA levels of SMS1, SMS2, and GAPDH in Jurkat and Molt4 cells were detected by semi-quantitative RT-PCR, as described under “Experimental Procedures.” One representative experiment is shown, and similar results were obtained in three independent experiments. B, SMS activities in Jurkat cells, Molt4 cells, and ZS cells were determined using C₆-NBD-ceramide as a substrate. Reaction mixtures containing cell lysates (50 μg of protein/lane) were incubated at 37 °C for 1 h. Values represent the mean ± S.D. from three independent experiments.