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Integrin-dependent tyrosine phosphorylation in corneal fibroblasts
S K Masur1, A Idris, K Michelson
1Department of Ophthalmology, Mount Sinai School of Medicine, City University of New York, NY 10029-6574, USA.
Investigative Ophthalmology & Visual Science
|August 1, 1995
Summary
Corneal fibroblast adhesion to fibronectin involves tyrosine phosphorylation of focal adhesion kinase (FAK). This signaling pathway is crucial for focal adhesion formation, highlighting the fibronectin receptor's role in extracellular matrix signaling.
Area of Science:
- Cell biology
- Biochemistry
- Extracellular matrix signaling
Background:
- Intracellular signaling pathways are critical for cell functions.
- Integrins mediate cell adhesion to the extracellular matrix.
- Tyrosine phosphorylation plays a key role in signal transduction.
Purpose of the Study:
- Investigate the role of tyrosine phosphorylation in integrin-dependent cell adhesion in corneal fibroblasts.
- Elucidate the signaling mechanisms involved in focal adhesion formation.
Main Methods:
- Used antibodies to detect phosphotyrosine-containing proteins and focal adhesion kinase (FAK).
- Localized phosphotyrosines and vinculin in fixed corneal fibroblasts.
- Examined FAK phosphorylation during cell attachment to different substrates.
Main Results:
- Corneal fibroblast suspension decreased phosphotyrosine levels.
- Fibronectin-dependent attachment induced tyrosine phosphorylation of FAK.
- Phosphotyrosine colocalized with vinculin in focal adhesions.
- Herbimycin A inhibited focal adhesion formation.
Conclusions:
- Fibronectin receptor signaling in corneal fibroblasts requires tyrosine kinase activation for focal adhesion formation.
- FAK phosphorylation is a key event in this process.
- The fibronectin receptor is important for extracellular matrix signaling in corneal fibroblasts.