Fig. 7. The 66-residue N-terminal region of SCD1 makes an otherwise stable ER membrane protein unstable. (A) CHO-K1 cells were transfected with plasmids carrying b5-EGFP cDNA or SCD66-b5-EGFP cDNA, grown for 48 hours, and analyzed by immunofluorescence microscopy. Fluorescence images of b5-EGFP and SCD66-b5-EGFP (green) and calnexin (red) were taken using a confocal microscope. Merged images are also shown. Bar, 10 µm. (B) Cells, prepared as above, were subjected to pulse-chase analysis with [³⁵S]methionine in the absence (DMSO) or presence of 2 µM epoxomicin. Other conditions were as described in Fig. 5.