This dataset provides global phosphoproteomic profiles of late-stage erythroblasts (day 15 of in vitro erythroid culture), comparing cells transfected with either control (pLKO.1-shLuc) or PIM1-targeting shRNA (pLKO.1-shPIM1). The data include three biological replicates per condition, enabling quantitative analysis of phosphorylation dynamics during terminal erythroid differentiation.