Evidence map›Paper›PMID 41731349›Full record

ArticleThe FEBS journal2026

Resistance-exercise-induced stress intervenes in TGF-β signaling by cooperatively downregulating nuclear αB-crystallin and SMAD4 in human skeletal muscle fibers.

Kirill Schaaf, Cassandra Duda, Tihomir Kostov, Patrick Diel, Käthe Bersiner, Wilhelm Bloch, Sebastian Gehlert, Daniel Jacko

Abstract read
In one paragraph

Article in The FEBS journal, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0citing papers in PubMed
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1 · What the graph read from it

What it found

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

8 authors.

Kirill SchaafDepartment of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Cologne, Germany.
Cassandra DudaDepartment of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Cologne, Germany.
Tihomir KostovDepartment of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Cologne, Germany.
Patrick DielDepartment of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Cologne, Germany.
Käthe BersinerDepartment for the Biosciences of Sports, Institute of Sports Science, University of Hildesheim, Hildesheim, Germany.
Wilhelm BlochDepartment of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Cologne, Germany.
Sebastian GehlertDepartment for the Biosciences of Sports, Institute of Sports Science, University of Hildesheim, Hildesheim, Germany.
Daniel JackoDepartment of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Cologne, Germany.ORCID https://orcid.org/0000-0002-9330-4702

Funding

Deutsche Forschungsgemeinschaft 388932620
6 · The paper itself

Abstract

Alpha-crystallin B chain (αB-crystallin; CRYAB) helps to maintain proteostasis following cellular stress. Additionally, recent studies in fibroblasts have shown its function in the transforming growth factor beta (TGF-β) pathway, where it stabilizes mothers against decapentaplegic homolog 4 (SMAD4) in the nucleus, enabling target gene transcription. Specifically in skeletal muscle fibers (SkMFs), TGF-β/SMAD4 signaling via myostatin regulates fiber size by inducing growth inhibitors and suppressing the serine/threonine-protein kinase (mTOR) pathway. Conversely, resistance exercise (RE) promotes muscle growth and should therefore affect CRYAB/SMAD4 interaction. However, in human SkMFs, CRYAB's nuclear localization and role in TGF-β/SMAD4 signaling, at rest or after RE, remain undescribed. Therefore, we first validated CRYAB's nuclear localization by small interfering RNA (siRNA)-mediated CRYAB silencing in C2C12 cells (mouse skeletal muscle myoblast cell line) and in human SkMFs via subcellular fractionation and confocal microscopy. To determine the effect of RE on this pathway, skeletal muscle biopsies were taken at rest and 60 min post-RE and analyzed for nuclear localization and phosphorylation of CRYAB and SMAD4, CRYAB/SMAD4 colocalization, and anabolic signaling. CRYAB was localized to C2C12 myoblast nuclei during proliferation but disappeared early during differentiation and was absent in nuclei of myotubes. In contrast, CRYAB was present in nuclei of resting human SkMFs. However, acute RE reduced total CRYAB in SkMF nuclei and increased its phosphorylation at serine 59, which likely promotes its export. Acute RE also reduced both nuclear and cytoplasmic SMAD4 while enhancing anabolic signaling by mTOR and small ribosomal subunit protein eS6 (rpS6) phosphorylation. We conclude that CRYAB and SMAD4 interact in nuclei of human SkMFs and have a coordinated regulation in response to RE-induced mechanical stress, revealing a new perspective on a yet-undescribed mechanism contributing to skeletal muscle adaptation.

Indexed as

alpha-Crystallin B ChainExerciseMuscle Fibers, SkeletalSmad4 ProteinTransforming Growth Factor betaAnimalsCell LineCell NucleusDown-RegulationHumansMiceMuscle, SkeletalSignal TransductionTOR Serine-Threonine Kinasesalpha-Crystallin B ChainCRYAB protein, humanSmad4 ProteinSMAD4 protein, humanTOR Serine-Threonine KinasesTransforming Growth Factor betaCRYABHSPB5musclenucleiresistance exerciseSMAD4TGF‐β

Identifiers

PMID41731349
PMCPMC13440606

What Socratic holds

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LicenceCC BY
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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.