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Fig. 3
Cdk5 regulates Pak1 activity in biliary epithelial cells. (A) Pak1 phosphorylation (T423) levels in control DMSO-treated and olomoucine-treated wild-type Tg(Tp1-MmHbb:EGFP)um14 larvae were analyzed by western blotting at 5 dpf. Phospho-Pak1 was increased in olomoucine-treated larvae, whereas total Pak1 protein levels remained constant. Tubulin served as a loading control. These experiments were repeated three times with similar results. (B,C) Projected images of 4 μm-thick confocal z-stacks of the liver in DMSO-treated (B) or olomoucine-treated (C) larvae visualized for phospho-Pak1 (T423) (red). Biliary epithelial cells are outlined. (B′,C′) Phospho-Pak1 visualization merged with Tg(Tp1-MmHbb:EGFP)um14 expression (green), DAPI staining (white) and F-actin (phalloidin, blue). Pak1 is predominantly activated in Tg(Tp1-MmHbb:EGFP)um14-positive biliary epithelial cells in the liver of olomoucine-treated larvae.