Cited by 887PI3K/AKT/mTOR signaling in cancerSignaling Pathways in DiseaseAutophagy in Disease and Therapy

Isolation of a Protein Target of the FKBP12-Rapamycin Complex in Mammalian Cells

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Sabers, Candace J., Martin, Mary M., Brunn, Gregory J., Williams, Josie M., Dumont, Francis J., Wiederrecht, Gregory, Abraham, Robert T.·1995·Journal of Biological Chemistry

Abstract

The immunosuppressive drug, rapamycin, interferes with an undefined signaling pathway required for the progression of G1-phase T-cells into S phase. Genetic analyses in yeast indicate that binding of rapamycin to its intracellular receptor, FKBP12, generates a toxic complex that inhibits cell growth in G1 phase. These analyses implicated two related proteins, TOR1 and TOR2, as targets of the FKBP12-rapamycin complex in yeast. In this study, we have used a glutathione S-transferase (GST)-FKBP12-rapamycin affinity matrix to isolate putative mammalian targets of rapamycin (mTOR) from tissue extracts. In the presence of rapamycin, immobilized GST-FKBP12 specifically precipitates similar high molecular mass proteins from both rat brain and murine T-lymphoma cell extracts. Binding experiments performed with rapamycin-sensitive and -resistant mutant clones derived from the YAC-1 T-lymphoma cell line demonstrate that the GST-FKBP12-rapamycin complex recovers significantly lower amounts of the candidate mTOR from rapamycin-resistant cell lines. The latter results suggest that mTOR is a relevant target of rapamycin in these cells. Finally, we report the isolation of a full-length mTOR cDNA that encodes a direct ligand for the FKBP12-rapamycin complex. The deduced amino acid sequence of mTOR displays 42 and 45% identity to those of yeast TOR1 and TOR2, respectively. These results strongly suggest that the FKBP12-rapamycin complex interacts with homologous ligands in yeast and mammalian cells and that the loss of mTOR function is directly related to the inhibitory effect of rapamycin on G1- to S-phase progression in T-lymphocytes and other sensitive cell types.

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  • Cyclosporin A forms a binary complex with cyclophilin that is able to bind and inhibit calcineurin.

    “Another example of an MG is Cyclosporin A, which forms a binary complex with cyclophilin able to bind and inhibit calcineurin.80,81”

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  1. Fruman, D. A., Klee, C. B., Bierer, B. E., and Burakoff, S. J. (1992) Proc. Nat/. Acad. Sci. U. S. A. 89, 3686-3690
  2. Calvo, V., Crews, C. M., Vik, T. A., and Bierer, B. E. (1992) Proc. Natl. Acad. Sci. U. S. A. 89,7571-7575

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Authors
Sabers, C. J., Martin, M. M., Brunn, G. J., Williams, J. M., Dumont, F. J., Wiederrecht, G., & Abraham, R. T.
Affiliations
  • Mayo Clinic (US)
  • Merck & Co., Inc., Rahway, NJ, USA (United States) (US)
Corresponding author
Abraham, Robert T.
Venue
Journal of Biological Chemistry
Publisher
Elsevier BV
Published
1995-01
Volume
270
Issue
2
Pages
815-822
ISSN
0021-9258 (ISSN-L)
OpenAlex
W2158612356
Cited by
887
References
29
Citations by year
2026: 10 · 2025: 20 · 2024: 28 · 2023: 37 · 2022: 38 · 2021: 37 · 2020: 39 · 2019: 31 · 2018: 25 · 2017: 38 · 2016: 25 · 2015: 31 · 2014: 26 · 2013: 31 · 2012: 29
FWCI
9.91
Type
journal article
Language
en
Open access
Locations
  • Journal of Biological Chemistry (publishedVersion, cc-by)
  • PubMed (publishedVersion)
Funders
  • Mayo Foundation for Medical Education and Research
  • National Institutes of Health
  • National Institute of General Medical Sciences (R01GM047286, GM47286)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › PI3K/AKT/mTOR signaling in cancer
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Signaling Pathways in Disease
  • Health Sciences › Medicine › Epidemiology › Autophagy in Disease and Therapy
Keywords
rapamycin, FKBP12, mTOR, TOR1, TOR2, G1/S transition, T cells, immunosuppressants, rapamycin resistance, YAC-1 cells, cDNA cloning
MeSH terms
Amino Acid Sequence, Animals, Base Sequence, Carrier Proteins, DNA-Binding Proteins, Fungal Proteins, Heat-Shock Proteins, Humans, Molecular Sequence Data, Polyenes, Protein Kinases, Tumor Cells, Cultured, Lymphoma, T-Cell, Rats, Sprague-Dawley, Sequence Homology, Amino Acid, Phosphotransferases (Alcohol Group Acceptor), DNA Primers, DNA, Complementary, Cell Cycle Proteins, Phosphatidylinositol 3-Kinases, Sirolimus, Tacrolimus Binding Proteins, Saccharomyces cerevisiae Proteins, Rats, TOR Serine-Threonine Kinases

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