![Fig. 6. Effect of cAMP pretreatment on 4E-BP1 phosphorylation levels. Factor-starved MO7e cells were cultured with [32P]orthophosphate in phosphate-free RPMI, as described in the Materials and Methods. Cells were treated with SLF in combination with GM-CSF (lanes 2, 4, and 6) for 1 hour or with 8-bromo-cAMP (lane 3), MIP-1α (lane 5), or IP-10 (lane 7) for 1 hour before cotreatment with GM-CSF and SLF for 1 hour. Control cells (lane 1) received vehicle alone. Immunoprecipitated 4E-BP1 proteins were separated by 12% SDS-PAGE and transfered to PVDF membranes, and the intensity of 32P-labeling was visualized by autoradiography. At left is the position of the molecular weight markers. 4E-BP1 appears as a doublet of two protein bands migrating with an approximate molecular weight of 16 to 17 kD, as indicated to the right of the figure. Similar results were obtained in each of two additional experiments.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/89/10/10.1182_blood.v89.10.3582/3/bl_0049f6.jpeg?Expires=1735839812&Signature=UfgYUHHOf7BfwUY6U-OpLRyUNRrWY4inz~28K1jAesNYVws5veZZFxezfsqwrWZ7jB503DEbFO9c42PWqX64mK~Pvu4ueVFPEu6XVwwzLXWzPDOozaWPhN3pNMlZITtkrMlofzm51BAnqlOz-g3G7Zgr9vmBiWfvy1R07wMldel2vR0gPu-lzaunJnG3fxE6ts6Sfkrr5AXaK3O5dBwd8m-422HxkkuwmzLwA03xcqs~tsFTJqmRpnmKUXcconnOFBLGdZhcwY9axQQme0ljxovbAAfNUzaQo0wJUwNSrvFeyE5dM3q5uxvz2OaigjwjaPyhPU0Ny~ogjrdwEWtutA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Effect of cAMP pretreatment on 4E-BP1 phosphorylation levels. Factor-starved MO7e cells were cultured with [32P]orthophosphate in phosphate-free RPMI, as described in the Materials and Methods. Cells were treated with SLF in combination with GM-CSF (lanes 2, 4, and 6) for 1 hour or with 8-bromo-cAMP (lane 3), MIP-1α (lane 5), or IP-10 (lane 7) for 1 hour before cotreatment with GM-CSF and SLF for 1 hour. Control cells (lane 1) received vehicle alone. Immunoprecipitated 4E-BP1 proteins were separated by 12% SDS-PAGE and transfered to PVDF membranes, and the intensity of 32P-labeling was visualized by autoradiography. At left is the position of the molecular weight markers. 4E-BP1 appears as a doublet of two protein bands migrating with an approximate molecular weight of 16 to 17 kD, as indicated to the right of the figure. Similar results were obtained in each of two additional experiments.
