Formation of P-selectin dimers in vitro.

Resting platelets were lysed in the absence (−) or presence (+) of alkylating agents NEM and IAA and then immunoprecipitated with a P-selectin–specific polyclonal antibody, as described in “Materials and methods.” In the first lane, cross-linker (DPDPB)–treated platelets were lysed in the presence of alkylating agents, and P-selectin was immunoprecipitated with the polyclonal antibody. Immunoprecipitates were separated on 6% SDS gels and analyzed by immunoblotting using the P-selectin monoclonal antibody AK4.