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Updated: Nov 30, 2025

Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model
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Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model

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c-Src kinase inhibits osteogenic differentiation via enhancing STAT1 stability

Zahra Alvandi1,2,3, Michal Opas1

  • 1Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.

Plos One
|November 12, 2020
PubMed

Insights

Proto-oncogene Src inhibits embryonic stem cell osteogenesis by preventing Runx2 nuclear entry. This involves stabilizing STAT1, which sequesters Runx2 in the cytoplasm, hindering bone formation.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Developmental Biology

Background:

  • Proto-oncogene Src is involved in cellular differentiation.
  • The role of Src in embryonic stem cell osteogenesis is largely unknown.

Purpose of the Study:

  • To investigate the role of c-Src in the osteogenic differentiation of mouse embryonic stem cells (mESCs) and MC3T3-E1 preosteoblasts.
  • To elucidate the molecular mechanism by which c-Src regulates osteogenesis.

Main Methods:

  • Utilized small molecule inhibitor PP2 and c-Src specific siRNAs.
  • Employed tet-inducible lentiviral vectors for c-Src overexpression.
  • Assessed Runt-related transcription factor 2 (Runx2) nuclear localization and transcriptional activity.
  • Investigated the role of Signal Transducer and Activator of Transcription 1 (STAT1) and protein degradation pathways.

Main Results:

  • c-Src demonstrated an inhibitory role in mESC and MC3T3-E1 osteogenic differentiation.
  • Active c-Src restricted Runx2 nuclear residency and transcriptional activity without affecting Runx2 expression levels.
  • STAT1 was essential for c-Src's inhibitory effect on Runx2 nuclear localization.
  • Elevated active c-Src increased STAT1 half-life by inhibiting proteasomal degradation, leading to increased cytoplasmic STAT1.
  • Cytoplasmic STAT1 bound Runx2, restricting its nucleocytoplasmic shuttling and reducing its transcriptional activity.

Conclusions:

  • c-Src inhibits osteogenesis by modulating Runx2 activity through STAT1.
  • This study defines a novel mechanism where c-Src regulates osteogenesis via STAT1-mediated inhibition of Runx2 nuclear translocation.

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