TSP-1 and CD36-binding peptides inhibit PKA signaling. (A) Platelets (3 × 10⁸/mL) were treated PGE₁ (0.1μM) alone for 1 minute, or TSP-1 (10 μg/mL) for 15 minutes followed by PGE₁ for 1 minute in the presence and absence of FA6-152 (1 μg/mL) or control IgG. Platelets were lysed, separated by SDS-PAGE, and blotted for phosphoVASP-ser¹⁵⁷, followed by reprobing for β-tubulin. Immunoblots are representative of 3 independent experiments. (B) Platelets (3 × 10⁸/mL) were treated with a CD36 binding peptide (0.001-10 μg/mL) for 15 minutes, then with PGE₁ for 1 minute, and then with PGE₁ for 1 minute. Platelets were then processed for immunoblotting as in panel A. (Ci) Platelets (3 × 10⁸/mL) were treated with a CD47 binding peptide (10 μg/mL) for 0-15 minutes followed by PGE₁ for 1 minute; platelets were then processed as in panel A. (Cii) Platelets (3 × 10⁸/mL) were treated with a CD47 binding peptide (0.001-10 μg/mL) for 15 minutes by PGE₁ for 1 minute, platelets were then processed as in panel A. All immunoblots are representative of 3 to 5 independent experiments.