TAFAZZIN deficient myeloid progenitors are more sensitive to apoptosis and ER stress signals. (A) Viability was assessed in vitro (CellTiter Glo) at 24 hours after exposure to ABT199, AMG176, or Thapsigargin. This assay was performed on >5 different days with multiple clones; the total N is displayed on each graph. The same data with error bars are displayed in supplemental Figure 5A. A 2-way analysis of variance (ANOVA) was used to determine the statistical difference between viability curves. (B) In vivo CHOP protein expression following thapsigargin treatment was assayed by intracellular antibody staining on peripheral blood neutrophils from adult mice transplanted and reconstituted with WT or TAFAZZIN-KO fetal liver hematopoietic cells as described in Figure 2A. CHOP expression was quantified as mean fluorescence intensity (MFI) by flow cytometry. (C) This experiment was repeated on additional mice to quantify CHOP as well as other intracellular proteins. The expression of CHOP and BiP in the peripheral blood circulating myeloid populations following treatment with thapsigargin demonstrated a trend toward increase in the TAFAZZIN-KO animals. t tests were performed, and P values are indicated on the plots. All other results are not statistically significant.