Figure 8. Decreased CTSD activity in RPE deficient of Cryba1. (A) CTSD activity in primary cultures of RPE cells from cKO mice was only about a third of normal. Starvation (St) to induce autophagy had no effect. (B) Overexpression of CRYBA1 in the cKO cells restored CTSD activity to the normal range. (C) CTSD activity was decreased by about 50% in freshly isolated RPE/choroid preparations from cKO mice as compared with Cryba1fl/fl samples. Activity was not significantly affected by induction of autophagy in vivo. Graphs show mean values and error bars represent s.d. from a triplicate experiment representative of at least 3 independent experiments. Statistical analysis was performed by a 2-tailed Student t test: *P < 0.05.