Fig. 1

PMA induces a rapid oxidation and loss of activity of SHP1 and SHP2 phosphatases. a) Oxidized SHP1 and SHP2 upon stimulation of HEL cells with 20 nM PMA. b) Oxidation western blots of SHP1 and SHP2 after 20 nM PMA stimulation in the presence or absence of 5 μM DPI. c) Simultaneous monitoring of SHP1 and PTP1B oxidation upon 20 nM PMA treatment. First lane shows an extract from HEL cells treated with VO₄^− 3 before protein extraction as a positive control for oxidation. d) Phosphatase activity of SHP1 and SHP2 from HEL cells treated with 20 nM PMA either alone (solid lines) or with 5 μM DPI (dashed lines) at different time points. Asterisks (*) indicate statistical significance versus the unstimulated condition (t = 0 h)