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Pull-down of Calmodulin-binding Proteins
Published on: January 23, 2012
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Calcium-dependent binding of Myc to calmodulin
Philipp Raffeiner1,2, Andrea Schraffl1, Thomas Schwarz3
1Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, A-6020 Innsbruck, Austria.
Oncotarget
|December 8, 2016
Summary
The calcium sensor calmodulin (CaM) interacts with the Myc oncoprotein, influencing its activity. This interaction, dependent on calcium levels, may fine-tune Myc
Area of Science:
- Molecular biology
- Cellular signaling
- Cancer research
Background:
- The Myc oncoprotein, a transcription factor, drives cellular processes and its deregulation is linked to cancer.
- Myc function is regulated by post-translational modifications and protein interactions.
- Calmodulin (CaM) is a key calcium sensor involved in numerous cellular signaling pathways.
Purpose of the Study:
- To investigate the interaction between calmodulin (CaM) and the Myc oncoprotein.
- To determine the Ca2+-dependence and binding site of the Myc:CaM interaction.
- To assess the functional consequences of the Myc:CaM interaction on Myc's transcriptional and oncogenic activities.
Main Methods:
- Biochemical assays to detect protein-protein interactions.
- Nuclear Magnetic Resonance (NMR) spectroscopy for structural and interaction analyses.
- Cell-based reporter assays and cell transformation assays to evaluate functional impact.
Main Results:
- A Ca2+-dependent physical interaction was identified between CaM and all Myc variants.
- The binding site for CaM on Myc was mapped to the conserved basic helix-loop-helix (bHLH) domain.
- CaM binds monomeric Myc with high affinity, but not Myc:Max heterodimers or Max homodimers.
- Increasing CaM levels enhance Myc's transcriptional and oncogenic activities, without affecting DNA binding.
Conclusions:
- Calmodulin (CaM) directly interacts with the Myc oncoprotein in a Ca2+-dependent manner.
- This interaction occurs primarily with monomeric Myc and is localized to the bHLH domain.
- Ca2+-bound CaM modulates Myc activity, suggesting a role in fine-tuning Myc's oncogenic functions.
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