Figure 5

The surface targeting and ligand internalization are abolished by fusing of exon 11 with SR-AI variant 341. A, Surface-targeted SR-A variants were detected by live immunostaining (red). Cytosolic SR-A variants were detected by immunocytochemistry (green). The yellow signal in the merged confocal images indicated that SR-AI and SR-AII were surface-targeted. Nuclei were counterstained with Hoechst 33258 (blue). B and C, Western blot analysis of total cell lysates and avidin pull-down of biotinylated lysates after PNGase F cleavage. D, Relative levels of surface-targeted SR-AI variants were quantified by densitometry. E, Western blot analysis of total cell lysates after PNGase F or Endo H cleavage. F, Lysates of COS-7 cells were immunoprecipitated with anti-SR-A antibody and subjected to Western blot analysis using anti-BiP. The experiments were repeated at least three times. G and H, Transfected cells were incubated with fluorescent oAβ and AcLDL followed by immunostaining using anti-SR-A antibody. Relative fluorescence intensities of internalized oAβ and AcLDL for more than 100 SR-A-positive cells were quantified using MetaMorph software. Bars indicate mean ± SEM of three independent experiments. Experimental groups labeled with different letters were significantly different from each other (p < 0.05).