MLN4924 upregulates REDD1 at mRNA and protein levels. (A) MM.1R cells were treated with 2.5 µM MLN4924 for 2, 4, 8, and 24 hours, increasing REDD1 mRNA levels as assessed by quantitative RT-qPCR. Values represent the relative expression ratio of REDD1 to GAPDH. (B) MM.1R cells were pretreated with DMSO or 10 µg/mL CHX for 1 hour, followed by DMSO or 2.5 µM MLN4924 for 2, 4, 8 hours, demonstrating an increase in protein level if protein synthesis is blocked.