Fig. 6. Inhibition of the proteasome leads to an increase of mutant opsin ER staining. Confocal immunofluorescence shows that inhibition of the proteasome machinery with MG-132 (5 µM for 8 hours) did not affect the processing of WT opsin. The treatment led to an increase in the level of P23H and K296E mutant opsin in the ER, as shown by colocalisation with the ER-resident Hsp70, BiP. Bar, 10 µm.