FIGURE 4.

Deletion of Nmp4 sensitizes MSPCs to pharmacological induction of ER stress. A, equal numbers of MSPCs were cultured for 24 h followed by treatment with or without tunicamycin for up to an additional 24 h. MTT activity was measured by the conversion of tetrazolium to formazan. B, caspase 3/7 activity was measured in MSPCs treated with tunicamycin for 24 h or no ER stress. C, MTT activity was measured in the MSPCs treated with tunicamycin or combined treatment with either salubrinal or torin 1. Relative values of three biological replicates are illustrated with the S.D. indicated for panels A, B, and C. Differences between treatment groups are indicated by asterisks (*), and differences between genotypes are indicated by a number (#) symbols.