[HTML][HTML] TSC2 integrates Wnt and energy signals via a coordinated phosphorylation by AMPK and GSK3 to regulate cell growth

K Inoki, H Ouyang, T Zhu, C Lindvall, Y Wang, X Zhang… - Cell, 2006 - cell.com
K Inoki, H Ouyang, T Zhu, C Lindvall, Y Wang, X Zhang, Q Yang, C Bennett, Y Harada…
Cell, 2006cell.com
Mutation in the TSC2 tumor suppressor causes tuberous sclerosis complex, a disease
characterized by hamartoma formation in multiple tissues. TSC2 inhibits cell growth by
acting as a GTPase-activating protein toward Rheb, thereby inhibiting mTOR, a central
controller of cell growth. Here, we show that Wnt activates mTOR via inhibiting GSK3 without
involving β-catenin-dependent transcription. GSK3 inhibits the mTOR pathway by
phosphorylating TSC2 in a manner dependent on AMPK-priming phosphorylation. Inhibition …
Summary
Mutation in the TSC2 tumor suppressor causes tuberous sclerosis complex, a disease characterized by hamartoma formation in multiple tissues. TSC2 inhibits cell growth by acting as a GTPase-activating protein toward Rheb, thereby inhibiting mTOR, a central controller of cell growth. Here, we show that Wnt activates mTOR via inhibiting GSK3 without involving β-catenin-dependent transcription. GSK3 inhibits the mTOR pathway by phosphorylating TSC2 in a manner dependent on AMPK-priming phosphorylation. Inhibition of mTOR by rapamycin blocks Wnt-induced cell growth and tumor development, suggesting a potential therapeutic value of rapamycin for cancers with activated Wnt signaling. Our results show that, in addition to transcriptional activation, Wnt stimulates translation and cell growth by activating the TSC-mTOR pathway. Furthermore, the sequential phosphorylation of TSC2 by AMPK and GSK3 reveals a molecular mechanism of signal integration in cell growth regulation.
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