Effect of dominant negative SNAP-23 expression on platelet function.

BACKGROUND: The protein SNAP-23 is part of the secretory pathway in platelets. It is, however, not entirely clear to what extent this protein contributes to the secretory function of platelets. Therefore, we overexpressed a dominant negative mutant with a novel technology that allows the creation of intact transgene-expressing platetets. RESULTS: Overexpression of a dominant negative SNAP-23 mutant that inhibited the binding of the native protein to the docking site within the secretory machinery resulted in significant suppression of the agonist-dependent surface recruitment of P-selectin and CD40L. Simultaneously, release from dense granules was clearly suppressed in the presence of this construct. Also agonist-dependent surface expression of fibrinogen receptor markers CD41 and CD61 was reduced, and agonist-triggered aggregation was inhibited. CONCLUSION: The dominant negative inhibition of SNAP-23 resulted in clear effects on platelet functions. The novel method using recombinant culture-derived platelets allowed the rapid clarification of the functional importance of this protein in intact platelets.