Moesin localization in resting and thrombin-treated platelets. (A) Resting platelets (0 minute) and platelets treated in suspension with thrombin for 1 to 5 minutes were cytocentrifuged, fixed, permeabilized, and double-stained with rabbit antimoesin (top) and rhodamine phalloidin (bottom). (B) Subcellular fractionation showing moesin distribution. Stirred resting and thrombin-treated platelets were lysed with Triton X-100 and fractionated9into low-speed pellet (cytoskeletal fraction), high-speed pellet (membrane skeleton fraction), and supernatant (soluble fraction). Immunoblots of fractions from 107 platelets show GPIIb (PMI-1 MoAb) and moesin (clone 38 MoAb; Transduction Labs, Lexington, KY). The Coomassie blue stained gels include, on the left, total lysate of resting platelets with major proteins identified. (C) Time course of moesin incorporation into the membrane skeleton (quantitation of immunoblots; mean ± SEM; n = 4 to 6).
