Platelet adhesion to collagen causes dephosphorylation of hsc70 and hsp90 phosphoprotein complexes. Immunoprecipitates (Ips) from lysates of ³²P-labeled platelets were separated by 10% SDS-PAGE minigels. The gels were dried and subjected to autoradiography. Cont refers to Ips from resting platelets and Adh to Ips from platelets adherent to collagen. (A) The two left lanes are anti-hsc70 Ips using the antibody 1B5; the two right lanes are anti-hsp90 Ips using the antibody AC88. (B) Silver stain of hsc70 immunoprecipitates. (C) Silver stain of hsp90 immunoprecipitates. An autoradiogram and silver stain of the gels representative for four experiments are presented.