Fig. 3. Mannose and glucose trimming play a role in the degradation of Tyr(C85S). (A) Diagram of the specific effects of the glucose and mannose analogues, n-butyl deoxynanojirimycin (DNJ) and deoxymannojirimycin (DMJ) on the trimming of the Glc₃Man₉GlcNAc₂ carbohydrate moiety. Triangles, circles, and squares indicate glucose, mannose, and N-acetyl-glucosamine residues, respectively. (B) Pulse-chase analysis of Tyr(C85S) mouse melanocytes incubated with DNJ as indicated and/or with DMJ throughout starvation, pulse and chase periods, except for samples designated with an asterisk which indicates post-translational addition. 0 and 3 hour time points are indicated in the graph as filled and open bars, respectively. (C) TYR(C89R) mRNA was translated in the presence Tyr(C85S) SP-melanocytes and resuspended in URL or buffer as described previously with or without DMJ and DNJ as indicated.