Fig 1: SOD3 is internalized by receptor-mediated endocytosis. (A) HMDMs were incubated with SOD3-cMyc (500 ng/ml) in the presence of increasing amounts of heparin as indicated for 90 min. Cells were subsequently washed, lysed and the recovered lysate analyzed by immunoprecipitation and SDS-PAGE/Western blotting. The uptake of SOD3 was evaluated by using the mAb 9E10 anti-cMyc. (B) The involvement of LRP1 in internalization was evaluated by incubating SOD3-cMyc in the presence of increasing molar ratios of RAP, an inhibitor of LRP1-ligand interactions. The cells were incubated in 90 min and the lysates analyzed as in (A). The experiments were repeated three times with similar results. This analysis shows that SOD3 is internalized into HMDMs via LRP1 interaction.