SPRY2 overexpression decreases B-cell viability and reduces ERK1/2 signaling activity. (A) Nalm-6 cells infected with control (vector) or SPRY2-expressing retroviruses (SPRY2) were evaluated for viability by MTT assay over a 4-day time course. The data are from triplicate samples normalized to day 0 absorbance at 570 nm, which is set to 1.0. (B) Nalm-6 cells infected with control (vector) or SPRY2-expressing retroviruses (SPRY2) were evaluated for apoptosis by annexin V–FITC and propidium iodide staining with flow cytometry. (C) Nalm-6 cells infected with a control (−) or SPRY2-expressing (+) retrovirus were evaluated for ERK1/2 phosphorylation after anti-IgM stimulation. Data are representative of 3 (B,C) or 4 (A) independent experiments.