Figure 4. MKP-1 interacts with Nrf2. (A) Endogenous MKP-1 and Nrf2 interacted in A549 cells. Cell lysate from A549 cells was immunoprecipitated with antibody specific to MKP-1 or Nrf2. IgG was used as negative control. After washing, the immunoprecipitates were analysed by immunoblotting with antibody specific to Nrf2 or MKP-1. Input, 10% of the cell lysate used for immunoprecipitation. (B) Endogenous MKP-1 co-localised with Nrf2 in A549 and H460 cells. Cells were grown on cover-slips and fixed. Indirect immunofluorescence staining was performed to visualize endogenous MKP-1 using a primary rabbit antibody against MKP-1, and followed by Texas Red goat anti-rabbit secondary antibody. The endogenous Nrf2 was visualized using a primary mouse antibody against Nrf2 and followed by EGFP anti-mouse secondary antibody. The endogenous MKP-1 and Nrf2 are shown in red and green, respectively. Nuclei were stained with DAPI (blue). The scale bars represent 10 μm. Results are representative of three separate experiments.