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Molecular Analysis of Endothelial-mesenchymal Transition Induced by Transforming Growth Factor-β Signaling
07:49

Molecular Analysis of Endothelial-mesenchymal Transition Induced by Transforming Growth Factor-β Signaling

Published on: August 3, 2018

N-terminal tyrosine phosphorylation of caveolin-2 negates anti-proliferative effect of transforming growth factor

Britain Abel1, Cara Willoughby, Sungchan Jang

  • 1Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA.

FEBS Letters
|July 24, 2012
PubMed

Insights

Tyrosine phosphorylation of caveolin-2 (Cav-2) counteracts the anti-proliferative effects of transforming growth factor beta (TGF-beta) in endothelial cells. This finding reveals a novel regulatory mechanism for TGF-beta signaling.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Transforming growth factor beta (TGF-beta) signaling is crucial for regulating endothelial cell proliferation.
  • Caveolin-2 (Cav-2) is a protein involved in various cellular processes, including signal transduction.
  • The role of Cav-2 phosphorylation in TGF-beta signaling remains incompletely understood.

Purpose of the Study:

  • To investigate the role of caveolin-2 (Cav-2) phosphorylation in regulating the anti-proliferative function of transforming growth factor beta (TGF-beta) in endothelial cells.
  • To determine how specific phosphorylation sites on Cav-2 affect TGF-beta-induced cellular responses.

Main Methods:

  • Utilized Cav-2 knockout endothelial cells.
  • Re-expressed wild-type and mutant forms of Cav-2 (Y19/27F-Cav-2 and S23/36A-Cav-2) via retroviral vectors.
  • Assessed the anti-proliferative effects of TGF-beta.
  • Analyzed TGF-beta-induced Smad3 phosphorylation and plasminogen activator inhibitor-1 (PAI-1) transcriptional activation.

Main Results:

  • Tyrosine phosphorylation of Cav-2 negatively regulates the anti-proliferative effect of TGF-beta.
  • Re-expression of Y19/27F-Cav-2 (non-tyrosine-phosphorylatable mutant) in Cav-2 knockout cells abolished the effect on TGF-beta's anti-proliferative function.
  • Re-expression of S23/36A-Cav-2 (serine phosphorylation mutant) partially reduced TGF-beta's anti-proliferative effect.
  • Differential effects of Cav-2 phosphorylation mutants correlated with Smad3 phosphorylation and PAI-1 activation.

Conclusions:

  • Tyrosine-phosphorylated Cav-2 acts as a negative regulator of TGF-beta's anti-proliferative activity in endothelial cells.
  • Specific phosphorylation events on Cav-2 differentially modulate TGF-beta signaling pathways.
  • This study elucidates a novel mechanism by which Cav-2 phosphorylation influences endothelial cell behavior in response to TGF-beta.

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