Fig. 8.

Analysis of glycosylated vs. unglycosylated SERT proteins. The source of 55-kDa band recognized by monoclonal SERT Ab in the trophoblast of GDM placentas was evaluated for differences in the N-glycosylation of the transporter protein (37, 39). Trophoblast (1.5 × 10⁶ per assay) from normal (N) and GDM placentas were treated with PNGase F and EndoH. The active site of each inhibitor is listed in Table 2. PNGase F treatment brought the 80-kDa band in normal and GDM trophoblast cells to the 55-kDa level (37). Immunoblot analyses were done with horseradish peroxidase-conjugated streptavidin as described in Methods. The positions of molecular mass standards run on the same gel are shown in kilodaltons. Averaged data from three independent experiments are presented. Quantifications of the WB analysis results were performed by densitometric scanning. Both treatments produced bands lower than the one observed in GDM trophoblast. The difference is indicated with red markers on the blots.