Figure 6. TSC2 is required for mTOR to localize away from lysosomes upon amino acid removal in a Rheb dependent manner.
(A-B) mTOR is released from lysosomes upon amino acid removal in control (A) but not TSC2-null MEFs (A’). This is rescued by re-expressing TSC2 + EGFP (to mark transfected cells) but not EGFP alone in the TSC-null MEFs (B). Note that the cell expressing TSC2 and GFP no longer has mTOR accumulated on lysosomes, whereas the surrounding, non-transfected cells retain lysosomally localized mTOR.
(C) Defective release of mTOR from lysosomes upon amino acid withdrawal in TSC2-null MEFs is rescued by knocking down Rheb. TSC2-null MEFs transfected with either Rheb siRNAs (upper panels) or control siRNAs (lower panels) treated 1h with +/− amino acid containing medium in the presence of dialyzed FBS.