RHEB in mTORC1:RHEB:GTP hydrolyses GTP

TSC2 (in the TSC complex) functions as a GTPase-activating protein and stimulates the intrinsic GTPase activity of the small G-protein Rheb. This results in the conversion of Rheb:GTP to Rheb:GDP. GDP-bound Rheb is unable to activate mTOR (Inoki et al. 2003, Tee et al. 2003). It is not demonstrated that RHEB hydrolyzes GTP when present in the mTORC1 complex; given the low affinity of RHEB for mTOR, it may dissociate from the mTORC1 complex before TSC2 stimulates hydrolysis of GTP; TSC2 may not have access to critical residues of RHEB when present inside mTORC1.

TSC2（位于TSC复合体中）作为一种GTPase激活蛋白，刺激小G蛋白Rheb的内源性GTPase活性。此过程导致Rheb:GTP向Rheb:GDP的转化。GDP结合态的Rheb无法激活mTOR（Inoki等，2003年，Tee等，2003年）。目前尚未证实RHEB在mTORC1复合体中存在时会发生GTP的水解；鉴于RHEB对mTOR的低亲和力，它可能在TSC2刺激GTP水解之前从mTORC1复合体中解离；当RHEB存在于mTORC1内部时，TSC2可能无法接触到Rheb的关键残基。