Related Experiment Videos
Src and Ras are involved in separate pathways in epithelial cell scattering
B Boyer1, S Roche, M Denoyelle
1Laboratoire de Compartimentation et Dynamique cellulaires, UMR CNRS 144, Institut Curie Section de Recherche, 26 rue d'Ulm F-75248 Paris Cedex 05, France. bboyer@curie.fr
The EMBO Journal
|October 6, 1997
Summary
Epidermal Growth Factor (EGF) triggers NBT-II carcinoma cell dispersion. Src kinases, unlike Ras, regulate this process independently of gene expression by directly organizing the cytoskeleton.
Area of Science:
- Cell Biology
- Molecular Biology
- Cancer Research
Background:
- Epidermal Growth Factor (EGF) signaling pathways regulate cell behavior.
- Src family kinases play a role in epithelial cell dispersion.
- NBT-II carcinoma cells serve as a model for studying cell scattering.
Purpose of the Study:
- To elucidate the distinct roles of Src kinases and Ras in EGF-induced epithelial cell dispersion.
- To investigate the molecular mechanisms by which Src kinases control cell scattering.
Main Methods:
- Microinjection of kinase-inactive Src (SrcK-) and Fyn (FynK-) mutants.
- Expression of dominant-negative N17Ras.
- Analysis of signaling pathway components (Shc, Grb2, MAPK).
- Assessment of gene expression using actinomycin D.
- Examination of cytoskeleton-associated protein phosphorylation (pp125FAK, cortactin).
Main Results:
- EGF activates Src and Yes kinases.
- Kinase-inactive Src and Fyn mutants inhibit cell scattering, with Fyn requiring SH2 and SH3 domains.
- Dominant-negative Ras also inhibits scattering, indicating Ras as a regulator.
- SrcK- expression does not affect early Ras pathway signaling (Shc phosphorylation, MAPK activation).
- Src kinases and Ras operate in separate pathways; N17Ras-induced block is rescued by Jun-Fos/Slug, but SrcK- block is not.
- Activated Ras-induced scattering requires RNA synthesis, while activated Src does not.
- SrcK- abolishes EGF-induced tyrosine phosphorylation of pp125FAK and cortactin.
Conclusions:
- Src kinases and Ras are distinct regulators of EGF-induced epithelial cell dispersion.
- Src kinases control cell scattering independently of gene expression, likely by directly modulating the cortical cytoskeleton.
- Ras-mediated cell dispersion involves gene expression and downstream effectors like Jun-Fos and Slug.