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Cell adhesion regulates the interaction between the docking protein p130(Cas) and the 14-3-3 proteins
M Garcia-Guzman1, F Dolfi, M Russello
1La Jolla Cancer Research Center, The Burnham Institute, La Jolla, California 92037, USA.
Abstract:
Integrin ligand binding induces a signaling complex formation via the direct association of the docking protein p130(Cas) (Cas) with diverse molecules. We report here that the 14-3-3zeta protein interacts with Cas in the yeast two-hybrid assay. We also found that the two proteins associate in mammalian cells and that this interaction takes place in a phosphoserine-dependent manner, because treatment of Cas with a serine phosphatase greatly reduced its ability to bind 14-3-3zeta. Furthermore, the Cas-14-3-3zeta interaction was found to be regulated by integrin-mediated cell adhesion. Thus, when cells are detached from the extracellular matrix, the binding of Cas to 14-3-3zeta is greatly diminished, whereas replating the cells onto fibronectin rapidly induces the association. Consistent with these results, we found that the subcellular localization of Cas and 14-3-3 is also regulated by integrin ligand binding and that the two proteins display a significant co-localization during cell attachment to the extracellular matrix. In conclusion, our results demonstrate that 14-3-3 proteins participate in integrin-activated signaling pathways through their interaction with Cas, which, in turn, may contribute to important biological responses regulated by cell adhesion to the extracellular matrix.
Insights
The 14-3-3zeta protein binds to p130(Cas) in a manner dependent on phosphoserine and cell adhesion. Integrin signaling regulates this interaction, impacting cell adhesion and biological responses.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Integrin signaling is crucial for cell adhesion and survival.
- p130(Cas) is a docking protein involved in integrin-mediated signaling.
- 14-3-3 proteins are key regulators of signal transduction.
Purpose of the Study:
- To investigate the interaction between 14-3-3zeta and p130(Cas).
- To determine the regulation of this interaction by cell adhesion and phosphorylation.
- To elucidate the role of this interaction in integrin-activated signaling pathways.
Main Methods:
- Yeast two-hybrid assay to detect protein-protein interactions.
- Co-immunoprecipitation in mammalian cells to confirm association.
- Treatment with serine phosphatase to assess phosphorylation dependence.
- Cell detachment and reattachment assays to study regulation by cell adhesion.
Main Results:
- 14-3-3zeta directly interacts with p130(Cas).
- The interaction is phosphoserine-dependent, reduced by serine phosphatase treatment.
- Integrin-mediated cell adhesion regulates the Cas-14-3-3zeta binding.
- Cell detachment diminishes the interaction, while reattachment to fibronectin rapidly induces it.
- Subcellular localization and co-localization of Cas and 14-3-3 are regulated by integrin ligand binding.
Conclusions:
- 14-3-3 proteins participate in integrin-activated signaling pathways via interaction with Cas.
- This interaction is a key component of biological responses regulated by cell adhesion.
- The findings provide insights into the molecular mechanisms of cell adhesion signaling.