Fig. 4

Effects of integrin β1 sialylation on sEV uptake. A Potential N-glycosylation sites (indicated by triangles) on integrin β1. Combined mutation to Asp of N-glycosylation sites 4–6 and 7–8 gave rise to Δ4–6 and Δ7–8. B Expression of WT integrin β1, Δ4–6, and Δ7–8 mutants. Tubulin was used as loading control. C Sialylation levels on integrin β1 in mutants by co-IP and western blotting. D Effects of mutant integrin β1 on sEV uptake. E–G HCV29 was treated with sEV from Y-vec, WT, and Δ7–8 mutant. Migratory ability (E), proliferation (F) and apoptosis (G) were determined. H Uptake of YTS-1 sEV in the presence of cilengitide (“RGD”). I Integrin β1/ FN interaction, assayed by co-IP and western blotting. J The interaction between integrin α5β1 and FN in cells expressing wild type integrin β1 and Δ7–8 mutant, assayed by co-IP and western blotting. K Integrin β1 and FN expression in sEV from Y-vec and Y-shβ1. TSG101 was used as loading control. L Integrin β1, α5 and FN levels in sEV from Y-vec and Y-shβ1. TSG101 was used as loading control