Figure 1.

REDD1 and TSC2 are required for inhibition of mTORC1 activity in response to hypoxia. Dephosphorylation of S6K (T389) and 4E-BP1 (T70) is observed in wild-type but not REDD1^−/− or TSC2^−/− cells. MEFs of each genotype growing in 10% serum were exposed to hypoxia (1% O₂) for the indicated times. The same blot was stripped and reprobed for the respective total proteins. Note the prominence of hypophosphorylated 4E-BP1 (lower band) upon hypoxic exposure of wild-type cells. β-Tubulin (b-tubulin) serves as a loading control.