Fig. 10. Treatment with 9-cis-retinal leads to an increase in soluble mutant opsin that reaches the plasma membrane. (A) Confocal immunofluorescence showing that overnight treatment of COS-7 cells expressing P23H-opsin leads to an increase in the amount of protein that reaches the plasma membrane. Bar, 10 µm. (B) A western blot using mAb 1D4 of P23H-opsin in total (T), DM-soluble (S) and DM-insoluble (P) protein extracts shows that the addition of 9-cis-retinal (+) dramatically increases the amount of opsin in the cells and that most of this is in the soluble fraction. The electrophoretic mobilities of different glycoforms of opsin are indicated: mature (40 kDa) (arrowhead); and immature forms (>41 kDa); deglycosylated form (30 kDa) (^*) and dimer (60 kDa) (^**). The positions of the molecular weight markers are indicated on the left in kDa.