Bipartite binding and partial inhibition links DEPTOR and mTOR in a mutually antagonistic embrace

TY - JOUR

T1 - Bipartite binding and partial inhibition links DEPTOR and mTOR in a mutually antagonistic embrace

AU - Heimhalt, Maren

AU - Berndt, Alex

AU - Wagstaff, Jane

AU - Anandapadamanaban, Madhanagopal

AU - Perisic, Olga

AU - Maslen, Sarah

AU - McLaughlin, Stephen

AU - Yu, Conny Wing Heng

AU - Masson, Glenn R.

AU - Boland, Andreas

AU - Ni, Xiaodan

AU - Yamashita, Keitaro

AU - Murshudov, Garib N.

AU - Skehel, Mark

AU - Freund, Stefan M.

AU - Williams, Roger L.

N1 - Funding Information: We acknowledge the MRC - Laboratory of Molecular Biology Electron Microscopy Facility for access and support of electron microscopy sample preparation and data collection. We thank Christos Savva, Rangana Warshamanage, Domagoj Baretić, Xiao-chen Bai, Rafael Fernández-Leiro and Sjors Scheres for expert assistance with cryo-EM data collection and processing. We thank Jake Grimmet and Toby Darling for implementing and maintaining the scientific computing infrastructure at the MRC LMB. We thank Christopher Johnson for training for the differential scanning fluorimetry and maintaining the Biophysics facility at the MRC LMB. We thank Yohei Ohashi for help with the initial mTORC1 purification. We thank Jaslyn Wong for providing purified mTORC1 A1459P and RHEB. MA was supported by FEBS fellowship and EMBO Advanced Fellowship (EMBO ALTF 603–2019). The work was supported by the Medical Research Council (MC_U105184308 to RLW) and Cancer Research UK (grant C14801/A21211 to RLW). Publisher Copyright: © Heimhalt et al.

PY - 2021/9/14

Y1 - 2021/9/14

N2 - The mTORC1 kinase complex regulates cell growth, proliferation, and survival. Because mis-regulation of DEPTOR, an endogenous mTORC1 inhibitor, is associated with some cancers, we reconstituted mTORC1 with DEPTOR to understand its function. We find that DEPTOR is a unique partial mTORC1 inhibitor that may have evolved to preserve feedback inhibition of PI3K. Counterintuitively, mTORC1 activated by RHEB or oncogenic mutation is much more potently inhibited by DEPTOR. Although DEPTOR partially inhibits mTORC1, mTORC1 prevents this inhibition by phosphorylating DEPTOR, a mutual antagonism that requires no exogenous factors. Structural analyses of the mTORC1/DEPTOR complex showed DEPTOR’s PDZ domain interacting with the mTOR FAT region, and the unstructured linker preceding the PDZ binding to the mTOR FRB domain. The linker and PDZ form the minimal inhibitory unit, but the N-terminal tandem DEP domains also significantly contribute to inhibition.

AB - The mTORC1 kinase complex regulates cell growth, proliferation, and survival. Because mis-regulation of DEPTOR, an endogenous mTORC1 inhibitor, is associated with some cancers, we reconstituted mTORC1 with DEPTOR to understand its function. We find that DEPTOR is a unique partial mTORC1 inhibitor that may have evolved to preserve feedback inhibition of PI3K. Counterintuitively, mTORC1 activated by RHEB or oncogenic mutation is much more potently inhibited by DEPTOR. Although DEPTOR partially inhibits mTORC1, mTORC1 prevents this inhibition by phosphorylating DEPTOR, a mutual antagonism that requires no exogenous factors. Structural analyses of the mTORC1/DEPTOR complex showed DEPTOR’s PDZ domain interacting with the mTOR FAT region, and the unstructured linker preceding the PDZ binding to the mTOR FRB domain. The linker and PDZ form the minimal inhibitory unit, but the N-terminal tandem DEP domains also significantly contribute to inhibition.

UR - https://www.scopus.com/pages/publications/85116278145

U2 - 10.7554/eLife.68799

DO - 10.7554/eLife.68799

M3 - Article

C2 - 34519269

AN - SCOPUS:85116278145

SN - 2050-084X

VL - 10

JO - eLife

JF - eLife

M1 - e68799

ER -