Personalized phosphoproteomics establish mTORC1 as a regulator of exercise-induced insulin sensitization in human skeletal muscle
Abstract
Exercise enhances skeletal muscle insulin sensitivity, but the signaling mechanisms responsible are poorly understood. Understanding them may open new therapeutic avenues for individuals with limited exercise capacity. Here, we used rapamycin to inhibit mTORC1 in combination with exercise and insulin stimulation in healthy men. A single dose of rapamycin enhanced the insulin-sensitizing effect of exercise by 53% on average compared to placebo. Responses varied widely across individuals (-40% to 218%), and we leveraged this variance through personalized phosphoproteomics to map the mTORC1-dependent signaling network in skeletal muscle. This identified the protein kinase MKNK2 as a candidate downstream effector, which we then targeted for functional validation. Pharmacological inhibition of MKNK2 with eFT508 in insulin-clamped mice reduced both whole-body and skeletal muscle insulin sensitivity, confirming a functional role for MKNK2 activity in muscle glucose uptake. We then used eFT508 in ex vivo incubated human skeletal muscle to map the signaling network downstream of MKNK2, identifying the translational initiator eIF4G1 as a further regulatory node. Together, these findings indicate that exercise-induced insulin sensitization is actively constrained by a negative feedback pathway running from mTORC1 through the translational regulators MKNK2 and eIF4G1, raising the possibility that rapid translation of unidentified target proteins contributes to fine-tuning glucose uptake.
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BibTeX
@misc{leandersson2026personalized,
title = {{Personalized phosphoproteomics establish mTORC1 as a regulator of exercise-induced insulin sensitization in human skeletal muscle}},
author = {M. R. Leandersson and H. Huckstep and J. D. Onslev and N. S. Henriksen and J. M. Kristensen and M. N. Zankel and R. Elmquist and J. T. E. Madsen and J. Solgaard Jensen and J. B. Birk and K. A. Sjoeberg and T. Wang and J. Petersen and J. R. Greenfield and D. E. James and E. Soendergaard and R. Kjoebsted and S. J. Humphrey and J. F. P. Wojtaszewski},
howpublished = {bioRxiv},
year = {2026},
month = aug,
doi = {10.64898/2026.08.27.747624},
url = {https://www.biorxiv.org/content/10.64898/2026.08.27.747624v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Personalized phosphoproteomics establish mTORC1 as a regulator of exercise-induced insulin sensitization in human skeletal muscle
AU - M. R. Leandersson
AU - H. Huckstep
AU - J. D. Onslev
AU - N. S. Henriksen
AU - J. M. Kristensen
AU - M. N. Zankel
AU - R. Elmquist
AU - J. T. E. Madsen
AU - J. Solgaard Jensen
AU - J. B. Birk
AU - K. A. Sjoeberg
AU - T. Wang
AU - J. Petersen
AU - J. R. Greenfield
AU - D. E. James
AU - E. Soendergaard
AU - R. Kjoebsted
AU - S. J. Humphrey
AU - J. F. P. Wojtaszewski
PY - 2026
DA - 2026/08/27
PB - bioRxiv
DO - 10.64898/2026.08.27.747624
UR - https://www.biorxiv.org/content/10.64898/2026.08.27.747624v1
AB - Exercise enhances skeletal muscle insulin sensitivity, but the signaling mechanisms responsible are poorly understood. Understanding them may open new therapeutic avenues for individuals with limited exercise capacity. Here, we used rapamycin to inhibit mTORC1 in combination with exercise and insulin stimulation in healthy men. A single dose of rapamycin enhanced the insulin-sensitizing effect of exercise by 53% on average compared to placebo. Responses varied widely across individuals (-40% to 218%), and we leveraged this variance through personalized phosphoproteomics to map the mTORC1-dependent signaling network in skeletal muscle. This identified the protein kinase MKNK2 as a candidate downstream effector, which we then targeted for functional validation. Pharmacological inhibition of MKNK2 with eFT508 in insulin-clamped mice reduced both whole-body and skeletal muscle insulin sensitivity, confirming a functional role for MKNK2 activity in muscle glucose uptake. We then used eFT508 in ex vivo incubated human skeletal muscle to map the signaling network downstream of MKNK2, identifying the translational initiator eIF4G1 as a further regulatory node. Together, these findings indicate that exercise-induced insulin sensitization is actively constrained by a negative feedback pathway running from mTORC1 through the translational regulators MKNK2 and eIF4G1, raising the possibility that rapid translation of unidentified target proteins contributes to fine-tuning glucose uptake.
ER -