Fig. 4.

Glycosylation assessment of different substrates. (A) Assessment of SHBG glycosylation. MAGT1^−/− TUSC3^−/− cells were cotransfected with SHBG and the indicated MAGT1 transcripts. (B) Metabolic labeling of the endogenous pCatC and GLUT1 in HEK293 cells and EBV-transformed lymphocytes. (C) HEK293 cells, primary fibroblasts, and EBV-transformed lymphocytes were analyzed for protein steady state levels of pCatC and CatC. β-Tubulin was used as a loading control. (D) Diagram showing the STT3B-dependent glycosylation site of GLUT1. The signal sequence is depicted in black. (E) Relative abundance of the 4- and 3-glycans form for pCatC. (F) Relative steady state levels of pCatC and CatC in primary fibroblasts and EBV-transformed lymphoctyes. CatC was not quantifiable in HEK293 cells. Quantified values are shown below gel lanes and represent the average number of glycans for the respective reporter (n = 3). EH indicates endoglycosidase H treatment. Error bars represent SEM. *P < 0.05.