Figure 5. Study of tyrosine kinase activity in RPE cells with confocal microscopy. For each pair of confocal images, the left panel shows the phosphotyrosine signals, and the right panel shows the overlay of protein, cytoskeleton, and nuclear stains (A) control RPE cells without any treatment, (B) treatment with nano chitosan (10 μM) for 5 h had no effect on tyrosine kinase expression, similar to the control, (C) peptide conjugated with nano chitosan (10 μM) increased the expression of tyrosine kinase proteins, (D) pretreatment for 1 h with tyrosine kinase blocker [Lavendustin-A (50 μM)] clearly suppressed protein expression, (E) incubation with peptide (10 μM) alone had no effect on the protein. Green: anti-phosphotyrosine antibody (Alexa Fluor 488); red: actin cytoskeleton (rhodamine-phalloidin stain); blue: nucleus (DAPI), (F) quantification of tyrosine kinase signals under different treatment conditions as described for A to E above.