Figure 5.

After treatment with BfA and recovery in nocodazole, the original GC pattern is recovered in myotubes but not in myoblasts. C2 myoblasts (a–b) or myotubes (c–g) were treated with 10 μg/ml BfA for 1 h (BfA), followed by 1-h recovery in the absence of drug (BfA → recov) or in the presence of 5 μg/ml nocodazole (BfA → noco). Also shown are control cells and a myotube treated with nocodazole alone (noco). At the end of the treatment, the cultures were stained with anti-giantin. BfA redistributes giantin to the ER, but the staining is more punctate than that of mannosidase, for which similar results were obtained. Treatment with nocodazole, as well as recovery from BfA in presence of nocodazole is known to redistribute GC proteins to the ER exit sites. In myoblasts recovered in the presence of nocodazole (b), the GC does not recover its initial distribution but remains fragmented compared with the control (a). In myotubes, giantin shows a similar distribution, whether it was redistributed to the ER exit sites (noco and BfA → noco), untreated (control), or recovered in drug-free medium (BfA → recov). Bar, 10 μm.