Cited by 44Metabolism, Diabetes, and CancerPI3K/AKT/mTOR signaling in cancerMuscle metabolism and nutrition

Role of Adenosine 5′-Monophosphate-Activated Protein Kinase Subunits in Skeletal Muscle Mammalian Target of Rapamycin Signaling

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Deshmukh, Atul S., Treebak, Jonas T., Long, Yun Chau, Viollet, Benoit, Wojtaszewski, Jørgen F. P., Zierath, Juleen R.·2008·Molecular Endocrinology

Abstract

AMP-activated protein kinase (AMPK) is an important energy-sensing protein in skeletal muscle. Mammalian target of rapamycin (mTOR) mediates translation initiation and protein synthesis through ribosomal S6 kinase 1 (S6K1) and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1). AMPK activation reduces muscle protein synthesis by down-regulating mTOR signaling, whereas insulin mediates mTOR signaling via Akt activation. We hypothesized that AMPK-mediated inhibitory effects on mTOR signaling depend on catalytic alpha2 and regulatory gamma3 subunits. Extensor digitorum longus muscle from AMPK alpha2 knockout (KO), AMPK gamma3 KO, and respective wild-type (WT) littermates (C57BL/6) were incubated in the presence of 5-aminoimidazole-4-carboxamide-1-beta-d-ribonucleoside (AICAR), insulin, or AICAR plus insulin. Phosphorylation of AMPK, Akt, and mTOR-associated signaling proteins were assessed. Insulin increased Akt Ser473 phosphorylation (P < 0.01), irrespective of genotype or presence of AICAR. AICAR increased phosphorylation of AMPK Thr172 (P < 0.01) in WT but not KO mice. Insulin stimulation increased phosphorylation of S6K1 (Thr389), ribosomal protein S6 (Ser235/236), and 4E-BP1 (Thr37/46) (P < 0.01) in WT, AMPK alpha2 KO, and AMPK gamma3 KO mice. However, in WT mice, preincubation with AICAR completely inhibited insulin-induced phosphorylation of mTOR targets, suggesting mTOR signaling is blocked by prior AMPK activation. The AICAR-induced inhibition was partly rescued in extensor digitorum longus muscle from either alpha2 or gamma3 AMPK KO mice, indicating functional alpha2 and gamma3 subunits of AMPK are required for the reduction in mTOR signaling. AICAR alone was without effect on basal phosphorylation of S6K1 (Thr389), ribosomal protein S6 (Ser235/236), and 4E-BP1 (Thr37/46). In conclusion, functional alpha2 and gamma3 AMPK subunits are required for AICAR-induced inhibitory effects on mTOR signaling.

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Crossref · 10.1210/me.2007-0448

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  • The α2 subunit of AMPK is required for AICAR-induced inhibitory effects of mTOR signaling in skeletal muscle.

    “The α2 subunit of AMPK is required for AICAR-induced inhibitory effects of mTOR signaling in skeletal muscle [159], which is consistent with alternative findings that showing that under basal conditions the α2 subunit rather than α1 subunit is required for AICAR-induced glucose uptake [26].”

    From AMPK and Exercise: Glucose Uptake and Insulin Sensitivity (2013) · cites this paper as [159]

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Authors
Deshmukh, A. S., Treebak, J. T., Long, Y. C., Viollet, B., Wojtaszewski, J. F. P., & Zierath, J. R.
Affiliations
  • Karolinska Institutet (SE)
  • University of Copenhagen (DK)
  • Institute Cochin (B.V.), 75016 Paris, France
Corresponding author
Zierath, Juleen R.
Venue
Molecular Endocrinology
Published
2008-05-01
Volume
22
Issue
5
Pages
1105-1112
ISSN
  • 0888-8809 (ISSN-L)
  • 1944-9917
OpenAlex
W2110061361
Cited by
44
References
42
Citations by year
2025: 1 · 2023: 1 · 2021: 2 · 2020: 1 · 2016: 4 · 2015: 1 · 2014: 2 · 2013: 7 · 2012: 3
FWCI
3.01
Type
journal article
Language
en
Open access
Locations
  • Molecular Endocrinology (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • Research at the University of Copenhagen (University of Copenhagen) (submittedVersion)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Metabolism, Diabetes, and Cancer
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › PI3K/AKT/mTOR signaling in cancer
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
Keywords
AMPK, mTOR signaling, skeletal muscle, insulin signaling, Akt phosphorylation, S6K1, 4E-BP1, ribosomal protein S6, AICAR, extensor digitorum longus, protein synthesis, energy sensing, translational regulation, AMPK knockout mice
MeSH terms
Animals, Female, Insulin, Multienzyme Complexes, Phosphorylation, Protein Kinases, Immunoblotting, Signal Transduction, Protein Serine-Threonine Kinases, Muscle, Skeletal, Protein Subunits, Mice, AMP-Activated Protein Kinases, TOR Serine-Threonine Kinases

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