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Published March 17, 2016 | Accepted Version + Supplemental Material
Journal Article Open

Glutamine Triggers Acetylation-Dependent Degradation of Glutamine Synthetase via the Thalidomide Receptor Cereblon


Cereblon (CRBN), a substrate receptor for the cullin-RING ubiquitin ligase 4 (CRL4) complex, is a direct protein target for thalidomide teratogenicity and antitumor activity of immunomodulatory drugs (IMiDs). Here we report that glutamine synthetase (GS) is an endogenous substrate of CRL4^(CRBN). Upon exposing cells to high glutamine concentration, GS is acetylated at lysines 11 and 14, yielding a degron that is necessary and sufficient for binding and ubiquitylation by CRL4^(CRBN) and degradation by the proteasome. Binding of acetylated degron peptides to CRBN depends on an intact thalidomide-binding pocket but is not competitive with IMiDs. These findings reveal a feedback loop involving CRL4^(CRBN) that adjusts GS protein levels in response to glutamine and uncover a new function for lysine acetylation.

Additional Information

© 2016 Elsevier B.V. Received: November 23, 2015; Revised: February 1, 2016; Accepted: February 26, 2016; Published: March 17, 2016. We thank W. Kaelin (Dana Farber Cancer Institute) for CRBN-KO 293FT cells. We also thank the R.J.D. lab for helpful discussions, particularly E. Blythe, R. Mosadeghi, W. den Besten, and A. Moradian (Proteome Exploration Laboratory/PEL) for their assistance, and R. Verma for insightful advice. J.E.L. was supported by a grant from National Research Council of Science and Technology (DRC-14-2-KRISS). The PEL is funded by the Gordon and Betty Moore Foundation (Grant GBMF775) and the Beckman Institute. T.V.N is supported by the Vietnam Education Foundation, a Brian D. Novis Research Award from the International Myeloma Foundation, and the Leukemia & Lymphoma Society. R.J.D. is an Investigator of the Howard Hughes Medical Institute, and this work was supported in part by HHMI. Author Contributions: T.V.N. and R.J.D., study conception and design, data analysis, and drafting of the manuscript with editorial assistance from other authors. T.V.N., all cellular and molecular experiments. J.E.L., mass spectrometry experiments in Figures 1A and S5 and Table S1. M.J.S. and S.H., mass spectrometry data analysis. M.J.S., protein sequence analysis. J.M.R. and S.G.L., analysis of the mass spectrometry data in Figure S5. J.S.H. and B.K., computational predictions of effects of mutations in the GS-binding site of CRBN and analysis of human GS structure in Figures S7B and S7C. J.-H.Y. and J.-S.J., quantification of glutamine and glutamate in serum and analysis of data in Figure 2G and Table S3. S.-J.Y., S.-J. J., and C.-S.P., mouse studies in Figures 2D–2F. H.H. provided essential reagents.

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Accepted Version - nihms780861.pdf

Supplemental Material - mmc1.pdf


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August 20, 2023
October 18, 2023