Abstract

The secreted protein Isthmin-1 (Ism1) mitigates diabetes by increasing adipocyte and skeletal muscle glucose uptake by activating the PI3K-Akt pathway. However, while both Ism1 and insulin converge on these common targets, Ism1 has distinct cellular actions suggesting divergence in downstream intracellular signaling pathways. To understand the biological complexity of Ism1 signaling, we performed phosphoproteomic analysis after acute exposure, revealing overlapping and distinct pathways of Ism1 and insulin. We identify a 53 % overlap between Ism1 and insulin signaling and Ism1-mediated phosphoproteome-wide alterations in ~ 450 proteins that are not shared with insulin. Interestingly, we find several unknown phosphorylation sites on proteins related to protein translation, mTOR pathway and, unexpectedly, muscle function in the Ism1 signaling network. Physiologically, Ism1 ablation in mice results in altered proteostasis, including lower muscle protein levels under fed and fasted conditions, reduced amino acid incorporation into proteins, and reduced phosphorylation of the key protein synthesis effectors Akt and downstream mTORC1 targets. As metabolic disorders such as diabetes are associated with accelerated loss of skeletal muscle protein content, these studies define a non-canonical mechanism by which this anti-diabetic circulating protein controls muscle biology.

Data availability

The phosphoproteomics dataset has been deposited to ProteomeXchange Consortium through JPost PXD031719 (JPST001484)(Okuda et al., 2017). The code for all analysis related to phosphoproteomic data is available at https://github.com/Svensson-Lab/Isthmin-1/tree/F442A_phosphoproteomics. The single-cell RNA sequencing data was re-analyzed from a previously published dataset (Baht et al., 2020). All the other data generated or analyzed in this study are included in the manuscript and supporting files.

The following data sets were generated
The following previously published data sets were used

Article and author information

Author details

  1. Meng Zhao

    Department of Pathology, Stanford University, Palo Alto, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5415-8335
  2. Niels Banhos Dannieskiold-Samsøe

    Department of Pathology, Stanford University, Palo Alto, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Livia Ulicna

    Department of Pathology, Stanford University, Palo Alto, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Quennie Nguyen

    Department of Pathology, Stanford University, Palo Alto, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Laetitia Voilquin

    Department of Pathology, Stanford University, Palo Alto, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-2138-4819
  6. David E Lee

    Duke Molecular Physiology Institute, Duke University, Durham, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. James P White

    Duke Molecular Physiology Institute, Duke University, Durham, United States
    Competing interests
    The authors declare that no competing interests exist.
  8. Zewen Jiang

    Department of Pathology, Stanford University, Palo Alto, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3852-8666
  9. Nickeisha Cuthbert

    Department of Pathology, Stanford University, Palo Alto, United States
    Competing interests
    The authors declare that no competing interests exist.
  10. Shrika Paramasivam

    Department of Pathology, Stanford University, Palo Alto, United States
    Competing interests
    The authors declare that no competing interests exist.
  11. Ewa Bielczyk-Maczynska

    Stanford Diabetes Research Center, Stanford University, Stanford, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-0558-1188
  12. Capucine Van Rechem

    Department of Pathology, Stanford University, Palo Alto, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5408-6124
  13. Katrin J Svensson

    Department of Pathology, Stanford University, Palo Alto, United States
    For correspondence
    katrinjs@stanford.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-5376-5128

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (DK125260)

  • Katrin J Svensson

National Institute of Diabetes and Digestive and Kidney Diseases (DK111916)

  • Katrin J Svensson

American Heart Association (905674)

  • Meng Zhao

American Heart Association (18POST34030448)

  • Ewa Bielczyk-Maczynska

National Heart, Lung, and Blood Institute (T32HL007057)

  • David E Lee

American Heart Association (882082)

  • Nickeisha Cuthbert

National Institute of Diabetes and Digestive and Kidney Diseases (DK116074)

  • Katrin J Svensson

National Institute on Aging (R21AG065943)

  • James P White

NIH Office of the Director (K01AG05666)

  • James P White

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Christopher Cardozo, Icahn School of Medicine at Mount Sinai, United States

Ethics

Animal experimentation: Animal experiments were performed per procedures approved by the Institutional Animal Care and Use Committee of the Stanford Animal Care and Use Committee (APLAC) protocol number #32982.

Version history

  1. Received: May 5, 2022
  2. Preprint posted: May 25, 2022 (view preprint)
  3. Accepted: September 27, 2022
  4. Accepted Manuscript published: September 28, 2022 (version 1)
  5. Version of Record published: October 24, 2022 (version 2)

Copyright

© 2022, Zhao et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Meng Zhao
  2. Niels Banhos Dannieskiold-Samsøe
  3. Livia Ulicna
  4. Quennie Nguyen
  5. Laetitia Voilquin
  6. David E Lee
  7. James P White
  8. Zewen Jiang
  9. Nickeisha Cuthbert
  10. Shrika Paramasivam
  11. Ewa Bielczyk-Maczynska
  12. Capucine Van Rechem
  13. Katrin J Svensson
(2022)
Phosphoproteomic mapping reveals distinct signaling actions and activation of muscle protein synthesis by Isthmin-1
eLife 11:e80014.
https://doi.org/10.7554/eLife.80014

Share this article

https://doi.org/10.7554/eLife.80014

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