Fig. 4
Maturation defective SorLA variants display reduced cell-surface levels of SorLA protein in HEK293 cells. Surface biotinylation experiments to examine cell-surface steady-state levels of SorLA protein in HEK293 cells expressing wild-type (WT) and SorLA variants. Total lysates (Total) and biotinylated fractions (Surface) were analyzed by immunoblotting using an anti-SorLA antibody. FUS, an intracellular protein, was used as an internal control. The absence of FUS staining in the biotinylated fraction demonstrates the integrity of the plasma membrane during the biotinylation experiment. The molecular masses of marker proteins in kDa are shown on the left. Maturation-deficient SorLA variants are underlined. The positions of immature core-glycosylated and mature complex-glycosylated SorLAFL are indicated with solid and empty arrowheads, respectively