Skip to main content
. Author manuscript; available in PMC: 2013 Sep 15.
Published in final edited form as: Free Radic Biol Med. 2012 Jun 23;53(6):1298–1307. doi: 10.1016/j.freeradbiomed.2012.06.024

Fig. 2. Accumulation of lutein and zeaxanthin in RPE cells prevents photo-oxidative inactivation of the proteasome in ARPE-19 cells.

Fig. 2

Confluent cultured ARPE-19 cells were loaded with A2E alone or loaded with A2E and then supplemented with 10 μM lutein or zeaxanthin for 3 days. The cells were then exposed to blue light for 10 min and harvested. The chymotrypsin-like activity of the proteasome in the cells was determined using a fluorogenic peptide as a substrate (panel A) and levels of ubiquitin conjugates were determined by Western blotting analysis using levels of β-actin as a loading control (panel B). The experiments were repeated twice with triplicates each time. The data in panel A are mean ± SD of the results from 6 samples in each group. The proteasome activity in control cells (neither treated with A2E nor exposed to blue light) was arbitrarily designated as 100 and the rest were expressed as relative activities. * indicates p<0.05 as compared the control cells. # indicates p<0.05 as compared to cells that were loaded with A2E and exposed to blue light.