Fig. 1. Degradation of exogenously expressed SCD1 is inhibited by proteasome inhibitors. CHO-K1 cells or HeLa cells were transfected with plasmids harboring SCD1-HA or TCR-flag cDNAs. After 48 hours culture, the cells were pulsed with [³⁵S]methionine in the presence of DMSO or 50 µM MG132 (A), and 20 or 100 µM leupeptin or 2 µM epoxomicin (epox) (B) for 30 minutes, then subjected to the chase reaction under the indicated conditions for the indicated times. Proteins (150 µg) were immunoprecipitated using anti-HA (for SCD1-HA) or anti-FLAG (for TCR-FLAG) antibodies and analyzed with an SDS-PAGE and BAS-2500 imager. Band intensities corresponding to SCD1-HA and TCR-flag were quantified by Image Gauge and shown by percentages of the signals setting those at time zero as 100%. The results shown are the average of three independent experiments. Asterisks: nonspecific immunoprecipitation bands.