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Dynamics of Fos-Jun-NFAT1 complexes
V R Ramirez-Carrozzi1, T K Kerppola
1Howard Hughes Medical Institute and Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109-0650, USA.
Summary
The orientation of Fos-Jun heterodimers in transcription complexes is influenced by NFAT1, affecting complex stability and gene activation. This binding orientation impacts both the dynamics and promoter selectivity of these regulatory complexes.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- Transcription initiation in eukaryotes involves complex nucleoprotein assemblies.
- These complexes form through protein interactions, either randomly or via specific pathways.
Purpose of the Study:
- To investigate the dynamics of Fos-Jun-NFAT1 complexes.
- To understand how NFAT1 influences Fos-Jun binding orientation.
- To determine the impact of binding orientation on complex stability and function.
Main Methods:
- Utilized multicolor fluorescence resonance energy transfer (FRET) assay.
- Measured energy transfer efficiencies to assess Fos-Jun reorientation.
- Analyzed dissociation rates and transcriptional activity.
Main Results:
- NFAT1 facilitates the reorientation of Fos-Jun heterodimers.
- Fos-Jun reorientation rate can exceed heterodimer dissociation rate.
- Favorable binding orientation enhances Fos-Jun-NFAT1 complex stability and transcriptional activity.
Conclusions:
- Heterodimer binding orientation is a critical factor in transcription complex dynamics and promoter selectivity.
- NFAT1's influence on Fos-Jun orientation optimizes transcription complex formation and function.