WT and NRBF2 KO MEFs were treated with DMSO, 1 μM thapsigargin(TP) or 1 μM tunicamycin (TN) for 24 or 48 h. (a) Then cells were either imaged under phase-contrast microscope or (b) stained with propidium iodide (PI) and subjected to cell death rate analysis by flow cytometry. The representative images of cell morphology after treatments and quantitative analysis of PI-positive cells rate show marked increase of cell death in the NRBF2 KO MEFs compared with WT MEFs. (Data are shown as mean±s.e.m., P values are indicated on the figure, unpaired Student's t-test, n=5). Scale bars, 100 μm; Con, control. 