Activation of both p72syk and Lyn by pervanadate treatment of intact erythrocytes.
Human erythrocytes were incubated without (histogram 1) or with pervanadate (histograms 2-5) either in the absence (histograms 1 and 2) or presence of PP1 (histograms 3-5). Erythrocyte membranes were then rapidly isolated and treated with extraction buffer as described in “Materials and methods.” The extracted proteins were immunoprecipitated with either anti-Syk (A) or anti-Lyn (B) antibodies, and tyrosine kinase activities of the immune complexes were tested in vitro as described in “Materials and methods.” Aliquots of packed membranes were also subjected to SDS-PAGE, transferred to nitrocellulose membranes, and incubated with either anti-Syk or anti-Lyn antibody (insets in both panels). Reported values represent means of 4 separate experiments, with SE indicated by vertical bars.
