FIG. 5.

Inhibition of glycosphingolipid catabolism augments glucosamine-induced ER stress responses. A: R28 cells were treated with CBE, an inhibitor of glucosylceramidase, for 2 weeks before plating for experimentation. Untreated and CBE-treated cells were then treated with glucosamine at the indicated dose for 24 h. Cellular lysate was subjected to Western blotting and analyzed for the expression of GRP78, CHOP, or β-actin. A representative blot of three separate experiments.