FIGURE 5.

Oxidized PTPs are excluded from DRMs. A, nonactivated RBL cells (Control) were lysed in 0.2% Triton X-100 and then subjected to sucrose density gradient ultracentrifugation. Individual fractions were collected from the top and analyzed with oxPTP mAb by immunoblotting (IB) for the presence of oxidized PTP. B, IgE-sensitized RBL cells were activated for 5 min with TNP/BSA (Ag; 0.5 μg/ml) and then analyzed as in A. C, RBL cells were activated with 1.6 mm H₂O₂ for 40 min and then analyzed as in A. D, RBL cells were activated with 0.2 mm Pv for 5 min and then analyzed as in A. E–H, BMMCs were nonactivated (E) or activated by antigen (F), H₂O₂ (G), or pervanadate (H) as RBL cells (see above). Distribution in individual fractions of Lyn kinase (a marker of membrane rafts), SHP-1, and HePTP is also shown. Representative data from three experiments are shown.