Activation of ERK2 at low concentrations of collagen depends on P2X1; correlation between ERK2 phosphorylation and platelet aggregation.
(A) Light transmission (%) recordings in apyrase-treated washed platelets stimulated with collagen (1 μg/mL) alone (control), in the presence of 0.5 μM α,β-meATP, or after preincubation with 0.5 μM ADP, 1 μM U-0126, 5 mM EGTA, 10 μM indomethacin, or 10 μM GF109203-X, as indicated. Time bar is included. (B) Parallel Western blot analyses of ERK2 phosphorylation in these platelet samples. The time course of ERK2 phosphorylation induced by 1 μg/mL collagen alone or in the presence of 0.5 μM α,β-meATP is shown. (C) The ERK2 phosphorylation detected in platelets stimulated with the same concentration of collagen for 4 minutes in the presence or absence of α,β-meATP, ADP, EGTA, GF109203-X, or indomethacin, as indicated.
