Related Experiment Videos
Involvement of the tyrosine kinase fer in cell adhesion
R Rosato1, J M Veltmaat, J Groffen
1Section of Molecular Carcinogenesis, Department of Pathology, Childrens Hospital of Los Angeles Research Institute and School of Medicine, University of Southern California, Los Angeles, California 90027, USA.
Abstract:
The Fer protein belongs to the fes/fps family of nontransmembrane receptor tyrosine kinases. Lack of success in attempts to establish a permanent cell line overexpressing it at significant levels suggested a strong negative selection against too much Fer protein and pointed to a critical cellular function for Fer. Using a tetracycline-regulatable expression system, overexpression of Fer in embryonic fibroblasts was shown to evoke a massive rounding up, and the subsequent detachment of the cells from the substratum, which eventually led to cell death. Induction of Fer expression coincided with increased complex formation between Fer and the cadherin/src-associated substrate p120(cas) and elevated tyrosine phosphorylation of p120(cas). beta-Catenin also exhibited clearly increased phosphotyrosine levels, and Fer and beta-catenin were found to be in complex. Significantly, although the levels of alpha-catenin, beta-catenin, and E-cadherin were unaffected by Fer overexpression, decreased amounts of alpha-catenin and beta-catenin were coimmunoprecipitated with E-cadherin, demonstrating a dissolution of adherens junction complexes. A concomitant decrease in levels of phosphotyrosine in the focal adhesion-associated protein p130 was also observed. Together, these results provide a mechanism for explaining the phenotype of cells overexpressing Fer and indicate that the Fer tyrosine kinase has a function in the regulation of cell-cell adhesion.
Insights
Overexpressing the Fer tyrosine kinase causes cell detachment and death by disrupting cell-cell adhesion complexes. This study reveals Fer
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- The Fer protein is a non-transmembrane receptor tyrosine kinase belonging to the fes/fps family.
- Previous attempts to create cell lines overexpressing Fer were unsuccessful, suggesting a critical role in cellular function.
Purpose of the Study:
- To investigate the cellular function of the Fer tyrosine kinase.
- To elucidate the mechanism by which Fer overexpression affects cell adhesion and viability.
Main Methods:
- Utilized a tetracycline-regulatable expression system to control Fer protein levels in embryonic fibroblasts.
- Analyzed protein complex formation, tyrosine phosphorylation levels, and adherens junction integrity.
- Employed co-immunoprecipitation assays to assess protein interactions.
Main Results:
- Fer overexpression induced massive cell rounding, detachment from the substratum, and eventual cell death.
- Increased complex formation between Fer and p120(cas), with elevated tyrosine phosphorylation of p120(cas).
- Fer overexpression led to increased tyrosine phosphorylation of beta-catenin and disruption of E-cadherin-catenin complexes within adherens junctions.
Conclusions:
- The Fer tyrosine kinase plays a crucial role in regulating cell-cell adhesion.
- Fer-mediated disruption of adherens junctions contributes to the observed cell detachment and death phenotype.
- Fer's function is critical for maintaining cellular integrity and adhesion.