1. Src kinases mediate TSP-1 inhibition of AC and PKA activity.
Src kinases mediate TSP-1 inhibition of AC and PKA activity. (A) Platelets (2 × 108/mL), incubated with either PP1 or PP3 (20μM), were preincubated with TSP-1 (10 μg/mL) or CD36 peptide (10μM) for 15 minutes followed by treatment with PGE1 (0.1μM) for 30 seconds. cAMP levels were measured as per manufacturer's instructions and are expressed as fmol cAMP/1 × 107 platelets. Data are presented as mean ± SEM of 4 individual experiments. §P < .05 for cAMP levels induced by PGE1 alone compared with the presence of TSP-1 or CD36 peptide. *P < .05 for cAMP levels induced by PGE1 in the presence TSP-1 or CD36 peptide, where platelets had been pretreated with PP1. (B) Platelets (3 × 108/mL), incubated with either PP1 (20μM), PP3 (20μM), JNK peptide inhibitor 1 (10μM), or SB (10μM), were preincubated with TSP-1 (10 μg/mL) for 15 minutes followed by treatment with PGE1 (0.1μM) for 1 minute. Samples were then lysed and phosphorVASPser157 was analyzed. (C) As in panel B, but the CD36 stimulatory peptide (10μM) was used in the place of TSP-1. All immunoblots are representative of 4 independent experiments.
Wayne Roberts et al. Blood 2010;116:
©2010 by American Society of Hematology