(d) Ba/F3 cells expressing FOXO3(A3)-ER were stimulated with 4-OHT in serum-free medium containing mIL-3. The medium was analysed for amino acid levels by high-performance liquid chromatography. Cells were lysed and analysed for protein levels of glutamine synthetase, p27 and actin (inset). Shown are the mean ±  s.e.m. of relative amino acid levels, compared with t=0 (n=4), and representative blots of these experiments. **P0.01. Uncropped images of blots are shown in Supplementary Fig. S7. 