Kinase inhibition of PMA-induced calcium influx.

Cell suspensions of Fluo-3/am–loaded RBCs were pretreated with (A) 3 μM staurosporine (thick line) or DMSO (thin line), (B) 1 μM K252A (thick line) or DMSO (thin line), and (C) 5 μM chelerythrine chloride (thick line), 10 μM chelerythrine chloride (dotted line), or DMSO (thin line) and then stimulated with 3 μM PMA and assayed for Fluo-3 fluorescence by flow cytometry. All preincubations were carried out for 10 minutes at 22°C. (D) Alternatively, Fluo-3/am–loaded RBCs were pretreated with 10 μM chelerythrine chloride or DMSO for 10 minutes at 22°C and then stimulated with 3 μM PMA and monitored in the fluorescence spectrophotometer as a function of time. Tracings representative of 4 different donors are shown.