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Updated: May 28, 2026
12:44
Electrophoretic Mobility Shift Assay (EMSA) for the Study of RNA-Protein Interactions: The IRE/IRP Example
Published on: December 3, 2014
Sam68 interacts with IRS1
R Quintana-Portillo1, A Canfrán-Duque, T Issad
1Department of Clinical Biochemistry, Virgen Macarena University Hospital, University of Seville, Spain.
Biochemical Pharmacology
|October 19, 2011
Summary
Sam68 protein interacts with IRS-1 in basal conditions. Insulin enhances this association, highlighting Sam68's role in early insulin receptor signaling.
Area of Science:
- Cellular Biology
- Molecular Signaling
- Biochemistry
Background:
- Sam68 (Src associated in mitosis) is an RNA-binding protein involved in linking cellular signaling to RNA processing.
- Previous research indicated insulin promotes Sam68 cytoplasmic relocalization, associating it with signaling molecules and positively modulating insulin action.
Purpose of the Study:
- To elucidate the role of Sam68 in the initial stages of insulin receptor (IR) signaling.
- To investigate the interaction between Sam68 and IRS-1 under basal and insulin-stimulated conditions.
Main Methods:
- Bioluminescence Resonance Energy Transfer (BRET) assays, including BRET saturation experiments.
- Co-immunoprecipitation assays.
- Utilized various Sam68 mutants to map interaction domains.
Main Results:
- Demonstrated for the first time that Sam68 associates with IRS-1 in basal conditions.
- Identified proline-rich domains (P0-P5) in Sam68 as important for IRS-1 binding affinity.
- Showed that insulin significantly increases the binding affinity between Sam68 and IRS-1 in HEK-293 cells.
Conclusions:
- Sam68 directly interacts with IRS-1 in basal conditions.
- Insulin enhances the affinity of the Sam68-IRS-1 interaction, suggesting a role in early IR signal transduction.
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