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Focal adhesion integrity is downregulated by the alternatively spliced domain of human tenascin

J E Murphy-Ullrich1, V A Lightner, I Aukhil

  • 1Department of Biochemistry, University of Alabama, Birmingham 35294.

The Journal of Cell Biology
|November 1, 1991
PubMed

Insights

Tenascin and similar matrix proteins reduce focal adhesions in endothelial cells. This effect, mediated by specific tenascin segments, is neutralized by certain GAGs, highlighting their role in cell adhesion modulation.

Area of Science:

  • Cell Biology
  • Extracellular Matrix
  • Protein Biochemistry

Background:

  • Tenascin, thrombospondin, and SPARC are matrix proteins influencing cell behavior.
  • Endothelial cells rely on focal adhesions for structural integrity and function.
  • Understanding matrix protein interactions is crucial for vascular biology.

Purpose of the Study:

  • To investigate the effect of tenascin on focal adhesions in endothelial cells.
  • To identify the specific domains and mechanisms responsible for tenascin's activity.
  • To explore the role of glycosaminoglycans in modulating tenascin's function.

Main Methods:

  • Dose-dependent addition of tenascin to bovine aortic endothelial cells.
  • Immunofluorescence microscopy to quantify focal adhesions.
  • Use of monoclonal antibodies and recombinant proteins to map active sites.
  • Testing various glycosaminoglycans for neutralizing activity.

Main Results:

  • Tenascin, thrombospondin, and SPARC significantly reduced focal adhesions in endothelial cells.
  • The alternatively spliced segment of tenascin was identified as the active site.
  • Chondroitin-6-sulfate effectively neutralized tenascin's activity, unlike other GAGs.

Conclusions:

  • Tenascin, thrombospondin, and SPARC act as soluble ligands that disrupt focal adhesions in endothelial cells.
  • The alternatively spliced domain of tenascin mediates this effect.
  • Galactosaminoglycans, particularly chondroitin-6-sulfate, can neutralize tenascin's activity, suggesting a role in cell adhesion regulation.

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