Figure 6. Extended time-course analysis of ethambutol (EMB)-induced elevation of membrane protein kinase C (PKCδ). RPE50 cells were treated with 8.0 mM EMB for 0, 1, 3, 6, and 24 h. A western blot of membrane PKC δ was performed. A non-specific band in the Ponceau S stained blot was included as an internal control. The result is representative of two repeated experiments. The relative ratios of the band intensity of PKC δ versus a non-specific band, taking the ratio of time zero as 1.0, are shown below.