Format

Send to

Choose Destination
Blood. 2018 Dec 13;132(24):2564-2574. doi: 10.1182/blood-2018-05-848515. Epub 2018 Sep 26.

UCH-L1 bypasses mTOR to promote protein biosynthesis and is required for MYC-driven lymphomagenesis in mice.

Author information

1
Department of Pediatric and Adolescent Medicine.
2
Department of Biochemistry and Molecular Biology.
3
Center for Individualized Medicine-Biomarker Discovery, and.
4
Department of Molecular Medicine, Mayo Clinic, Rochester, MN.
5
Enabling Technology Group, Sanford Research, Sioux Falls, SD.
6
Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD; and.
7
Division of Pediatric Hematology-Oncology, Mayo Clinic, Rochester, MN.

Abstract

The mechanistic target of rapamycin (mTOR) is a central regulator of cellular proliferation and metabolism. Depending on its binding partners, mTOR is at the core of 2 complexes that either promote protein biosynthesis (mTOR complex 1; mTORC1) or provide survival and proliferation signals (mTORC2). Protein biosynthesis downstream of mTORC1 plays an important role in MYC-driven oncogenesis with translation inhibitors garnering increasing therapeutic attention. The germinal center B-cell oncogene UCHL1 encodes a deubiquitinating enzyme that regulates the balance between mTOR complexes by disrupting mTORC1 and promoting mTORC2 assembly. While supporting mTORC2-dependent growth and survival signals may contribute to its role in cancer, the suppression of mTORC1 activity is enigmatic, as its phosphorylation of its substrate 4EBP1 promotes protein biosynthesis. To address this, we used proximity-based proteomics to identify molecular complexes with which UCH-L1 associates in malignant B cells. We identified a novel association of UCH-L1 with the translation initiation complex eIF4F, the target of 4EBP1. UCH-L1 associates with and promotes the assembly of eIF4F and stimulates protein synthesis through a mechanism that requires its catalytic activity. Because of the importance of mTOR in MYC-driven oncogenesis, we used novel mutant Uchl1 transgenic mice and found that catalytic activity is required for its acceleration of lymphoma in the Eμ-myc model. Further, we demonstrate that mice lacking UCH-L1 are resistant to MYC-induced lymphomas. We conclude that UCH-L1 bypasses the need for mTORC1-dependent protein synthesis by directly promoting translation initiation, and that this mechanism may be essential for MYC in B-cell malignancy.

PMID:
30257881
PMCID:
PMC6293873
[Available on 2019-12-13]
DOI:
10.1182/blood-2018-05-848515

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center