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Published on: May 2, 2019
Phosphoproteomic identification of a PDX-1/14-3-3ε interaction in pancreatic beta cells
1Department of Medical Biochemistry and Molecular Biology, University of Greifswald, Greifswald, Germany.
Abstract:
Glucose-dependent activation of the homeodomain transcription factor PDX-1 leads to its phosphorylation, to an increase in DNA binding capacity, and to NLS dependent translocation into the nucleus. To uncover unknown mediators of PDX-1 activation, PDX-1 interacting proteins were analysed by pull-down from (32)P-labelled, glucose-stimulated MIN6 cells. Recovered proteins were analysed by 2D gel electrophoresis and mass spectrometry. We identified 14-3-3ε as a novel PDX-1 binding protein and confirmed the interaction in vivo by Fluorescence Resonance Energy Transfer (FRET) analysis. We propose that 14-3-3ε interacts directly with PDX-1 to regulate its cellular distribution in pancreatic beta cells.
Insights
Glucose stimulates pancreatic beta cell transcription factor PDX-1 activation. Researchers identified 14-3-3ε as a novel binding protein, regulating PDX-1
Area of Science:
- Molecular biology
- Cell biology
- Endocrinology
Background:
- Glucose metabolism regulates pancreatic beta cell function.
- PDX-1 (Insulin gene transcription factor) is crucial for beta cell development and function.
- PDX-1 activation involves phosphorylation, increased DNA binding, and nuclear translocation.
Purpose of the Study:
- To identify novel proteins that mediate PDX-1 activation by glucose.
- To investigate the interaction between PDX-1 and its binding partners.
Main Methods:
- Pull-down assays using (32)P-labeled, glucose-stimulated MIN6 cells.
- 2D gel electrophoresis and mass spectrometry for protein identification.
- Fluorescence Resonance Energy Transfer (FRET) for in vivo interaction confirmation.
Main Results:
- Identified 14-3-3ε as a novel PDX-1 binding protein.
- Confirmed the interaction between 14-3-3ε and PDX-1 in vivo using FRET.
- Demonstrated that 14-3-3ε binds directly to PDX-1.
Conclusions:
- 14-3-3ε is a novel regulator of PDX-1.
- The interaction between 14-3-3ε and PDX-1 likely modulates PDX-1's cellular distribution in pancreatic beta cells.
- This finding provides new insights into glucose-mediated regulation of beta cell function.
