Structural basis for the recruitment and selective phosphorylation of Akt by mTORC2 PMID: 41308123

ADC Targets in Oncology

2026-04-10

Structural basis for the recruitment and selective phosphorylation of Akt by mTORC2

Science. 2025 Nov 27:eadv7111. doi: 10.1126/science.adv7111.

Martin S Taylor ^# ¹ ² ³ ⁴ , Maggie Chen ^# ⁵ ⁶ ⁷ , Matthew Hancock ^# ⁸ ⁹ ¹⁰ , Maximilian Wranik ^# ¹¹ ¹² ¹³ , Bryant D Miller ⁵ ¹⁴ ¹⁵ , Timothy R O'Meara ⁵ ⁶ , Brad A Palanski ⁵ ⁶ , Scott B Ficarro ¹⁶ ¹⁷ , Brian J Groendyke ¹⁶ , Yufei Xiang ¹⁸ ¹⁹ , Kazuma T Kondo ¹ ² ³ ⁴ ⁵ , Karen Y Linde-Garelli ¹¹ ¹² ¹³ , Michelle J Lee ¹¹ ¹² ¹³ , Dibyendu Mondal ⁸ ⁹ ¹⁰ , Daniel Freund ²⁰ , Samantha Congreve ²⁰ , Kaay Matas ²⁰ , Maximiliaan Hennink ²⁰ , Kera Xibinaku ²⁰ , Max L Valenstein ²¹ , Trevor van Eeuwen ²² , Jarrod A Marto ¹⁶ ¹⁷ , Andrej Sali ⁸ ⁹ ¹⁰ , Yi Shi ¹⁸ ¹⁹ , Nathanael S Gray ¹² ¹³ , David M Sabatini ²³ ²⁴ , Nam Chu ²⁵ , Kacper B Rogala ¹¹ ¹² ¹³ , Philip A Cole ⁵ ⁶

Affiliations

1. Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA.
2. Brown Center on the Biology of Aging, Brown University, Providence, RI, USA.
3. Legorreta Cancer Center, Brown University, Providence, RI, USA.
4. Department of Pathology, Massachusetts General Hospital, and Harvard Medical School, Boston, MA, USA.
5. Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA.
6. Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
7. Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
8. Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA.
9. Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA.
10. Quantitative Biology Institute, University of California, San Francisco, San Francisco, CA, USA.
11. Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.
12. Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA.
13. Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA.
14. Department of Pathology, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, USA.
15. Johns Hopkins University School of Medicine, Baltimore, MD, USA.
16. Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.
17. Center for Emergent Drug Targets and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, MA, USA.
18. Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA.
19. Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
20. Whitehead Institute for Biomedical Research, Cambridge, MA, USA.
21. Department of Medicine, Massachusetts General Hospital, Boston, MA, USA.
22. Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA.
23. Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic.
24. Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Boston Branch, Cambridge, MA, USA.
25. Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
# Contributed equally.

Abstract

The mTOR protein kinase forms two multiprotein complexes, mTORC1 and mTORC2, that function in distinct signaling pathways. mTORC1 is regulated by nutrients, and mTORC2 is a central node in phosphoinositide-3 kinase (PI3K) and small guanosine triphosphate Ras signaling networks commonly deregulated in Cancer and diabetes. Although mTOR phosphorylates many substrates in vitro, in cells, mTORC1 and mTORC2 have high specificity: mTORC2 phosphorylates the protein kinases Akt and PKC, but not closely related kinases that are mTORC1 substrates. To understand how mTORC2 recognizes substrates, we created semisynthetic probes to trap the mTORC2-Akt complex and determine its structure. Whereas most protein kinases recognize Amino acids adjacent to the phosphorylation site, local sequence contributes little to substrate recognition by mTORC2. Instead, the specificity determinants were secondary and tertiary structural elements of Akt that bound the mTORC2 component mSin1 distal to the mTOR active site and were conserved amongst at least 18 related substrates. These results reveal how mTORC2 recognizes its canonical substrates and may enable the design of mTORC2-specific inhibitors.