Effect of PP1 upon lyn activity in a cell-free system and intact cells.
The in vitro and in vivo efficacy of PP1 upon lyn kinase activity was determined in 3 independent experiments. The results are expressed as a percentage of the control (ie, unstimulated eosinophils). (A) In vitro results shown are representative graph. Eosinophils were incubated at 37°C for 5 minutes, and then lyn was immunoprecipitated from control (▪) and LTB4-stimulated (□) eosinophils at 20 seconds. Cell lysates were then preincubated with the indicated concentration of PP1 for 5 minutes at 4°C, and the lyn activity was determined by immunocomplex assay. (B) In vivo results shown as the means ± SEM. Eosinophils were preincubated at 37°C for 5 minutes with the indicated PP1 concentration. Lyn kinase was then immunoprecipitated from control (▪) and LTB4-stimulated (□) eosinophils at 5 seconds, and activity was determined by immunocomplex assay.
