Structural insights into TSC complex assembly and GAP activity on Rheb [post]

Huirong Yang, Zishuo Yu, Xizi Chen, Jiabei Li, Ningning Li, Jiaxuan Cheng, Ning Gao, Hai-Xin Yuan, Dan Ye, Kun-Liang Guan, Yanhui Xu
2020 unpublished
Tuberous sclerosis complex (TSC) integrates upstream stimuli and regulates cell growth by controlling the activity of mTORC1. TSC functions as a GTPase-activating protein (GAP) towards small GTPase Rheb and inhibits Rheb-mediated activation of mTORC1. Mutations in TSC genes cause tuberous sclerosis. In this study, the near-atomic resolution structure of human TSC complex reveals an arch-shaped architecture, with a 2:2:1 stoichiometry of TSC1, TSC2, and TBC1D7. This asymmetric complex consists
more » ... complex consists of two interweaved TSC1 coiled-coil and one TBC1D7 that spans over the tail-to-tail TSC2 dimer. The two TSC2 GAP domains are symmetrically cradled within the core module formed by TSC2 dimerization domain and central coiled-coil of TSC1. Structural and biochemical analyses reveal TSC2 GAP-Rheb complimentary interactions and suggest a catalytic mechanism, by which an asparagine thumb (N1643) stabilizes γ-phosphate of GTP and accelerate GTP hydrolysis of Rheb. Our study reveals mechanisms of TSC assembly and GAP activity.
doi:10.21203/ fatcat:u6k5d27gojhc5ku4hpcovtv7ku