Figure 8.

Effect of N-glycan deletions on α_Vβ₃ and α₅β₁ ligand binding. (A) Locations of α_V N-glycan sites in the crystal structure of α_Vβ₃ (PDB code 4G1E). (B) Locations of β₃ N-glycan sites in the crystal structure of α_Vβ₃ (PDB code 4G1E). Asn residues are shown as sticks with carbons in cyan. N-glycan residues resolved in the crystal structure are shown as sticks with carbons in magenta. Oxygens and nitrogens are red and blue, respectively. (C) Fibronectin (Fn) binding of HEK293FT-α₅β₁-KO cells transfected with the β₃ WT or the glycan mutants and α_V WT. (D) Fn binding of HEK293FT-α₅β₁-KO cells transfected with the indicated β₃ constructs and the α_V-GAAKR mutant that mimics integrin inside-out activation. (E) Fn binding of HEK293FT-α₅β₁-KO cells transfected with the α_V WT or the glycan mutants and β₃ WT. (F) Locations of selected N-glycans at the βI domain of β₁ integrin in the crystal structure of α₅β₁ headpiece (PDB code 4WJK). Asn and glycans are shown as sticks. Color codes are the same as panels A and B. Metal ions at the ligand-binding site are shown as spheres. (G) Fn binding of HEK293FT-α₅β₁-KO cells transfected with the β₁ WT or the selected glycan mutants and α₅ WT. Fn binding was done in the presence of 1 mM Ca²⁺/Mg²⁺ (Ca/Mg) or 0.2 mM Ca²⁺ plus 2 mM Mn²⁺ (Ca/Mn). Data are means ± s.e.m. (n = 3).