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A Ras-GTPase-activating protein SH3-domain-binding protein
F Parker1, F Maurier, I Delumeau
1Gene Medicine Department, Rhône-Poulenc Rorer, Centre de Recherche de Vitry-Alfortville, Vitry Sur Seine, France.
Molecular and Cellular Biology
|June 1, 1996
Summary
Researchers purified G3BP, a protein that binds to Ras-GTPase-activating protein (GAP). This binding is crucial for Ras signaling and occurs when cells are proliferating.
Area of Science:
- Molecular Biology
- Cell Signaling
- Protein Biochemistry
Background:
- Ras signaling pathways are critical for cell growth and proliferation.
- Ras-GTPase-activating protein (GAP) plays a key role in regulating Ras activity.
- The SH3 domain of GAP is essential for Ras signaling.
Purpose of the Study:
- To identify and characterize proteins that bind to Ras-GAP.
- To elucidate the role of G3BP in Ras signaling.
Main Methods:
- Protein purification and coimmunoprecipitation assays were used to identify G3BP.
- cDNA sequencing was performed to determine the G3BP protein sequence.
- Recombinant G3BP was used to study its binding to the GAP SH3 domain.
Main Results:
- A ubiquitously expressed cytosolic protein, G3BP, was purified and found to coimmunoprecipitate with GAP.
- G3BP physically associates with the SH3 domain of GAP.
- G3BP shares structural features with heterogeneous nuclear RNA-binding proteins.
- G3BP binds to the GAP SH3 domain and coimmunoprecipitates with GAP in proliferating cells.
Conclusions:
- G3BP is a novel protein that binds to the SH3 domain of Ras-GAP.
- The interaction between G3BP and GAP is regulated by the cellular proliferation state.
- This suggests a potential role for the GAP-G3BP complex in activated Ras signaling pathways.