Surface plasmon resonance and competition studies of 14-3-3, talin, and filamin interactions with β2 cytoplasmic peptides. (A) Surface plasmon resonance (Biacore) sensorgrams of 14-3-3 binding to the phosphorylated (pT) and unphosphorylated (T) β2 peptide. The 14-3-3 concentrations used were 40, 160, 320, 640, and 1000 nM. (B) Surface plasmon resonance (Biacore) sensorgrams of talinF2/F3 binding to the phosphorylated (pT) and unphosphorylated (T) β2 peptide. The concentrations of talin used were 4, 10, 20, 40, and 60 nM. (C) Surface plasmon resonance (Biacore) sensorgrams of IgFLNa21 binding to the phosphorylated (pT) and unphosphorylated (T) β2 peptide. The concentrations of FLN used were 100, 200, and 400 μM. (D) Binding of filamin and 14-3-3 from ARAApSAPA-treated lysates to integrin peptide affinity columns. ARAApSAPA significantly reduced the interaction between 14-3-3 and β2 integrin peptide. The binding of filamin to wt integrin peptide or to the pT integrin peptide is not significantly increased in ARAApSAPA-treated lysates. Equal loading was confirmed by Western blotting of 14-3-3 from lysates (not shown). − indicates no ARAApSAPA treatment; +, 10 μM ARAApSAPA treatment.