Structural plasticity of the coiled-coil interactions in human SFPQ
Heidar J Koning1, Jia Y Lai1, Andrew C Marshall1
1School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
Nucleic Acids Research
|December 19, 2024
Summary
SFPQ and NONO proteins form polymers through coiled-coil interactions, influencing paraspeckle assembly and cellular functions. This study reveals novel coiled-coil interfaces critical for DBHS protein polymerization and disease association.
Area of Science:
- Molecular Biology
- Structural Biology
- Cellular Biology
Background:
- SFPQ (splicing Factor Proline/Glutamine rich) and NONO (non-POU domain-containing octamer-binding protein) are DBHS proteins crucial for RNA regulation.
- They form paraspeckles, sub-nuclear bodies involved in cellular homeostasis and neurological diseases.
- Their interactions, including dimerization and polymerization, are key to their function.
Purpose of the Study:
- To define and dissect the coiled-coil interactions governing DBHS protein polymerization.
- To elucidate the structural basis of SFPQ/NONO heterodimerization and polymerization.
- To investigate the role of novel coiled-coil interfaces in DBHS protein assembly.
Main Methods:
- Crystal structure determination of an SFPQ/NONO heterodimer.
- Solution small-angle X-ray scattering (SAXS) experiments.
- Analysis of various SFPQ/NONO heterodimer variants (QM mutant, ΔCSAH variant, disulfide-forming variant).
Main Results:
- A flexible coiled-coil interaction interface in the SFPQ/NONO heterodimer was revealed, differing from previous findings.
- Newly characterized coiled-coil interfaces contribute to DBHS protein polymerization.
- Specific mutations (QM, ΔCSAH, R542C) modulated tetramerization, impacting DBHS protein behavior.
Conclusions:
- Novel coiled-coil interfaces are critical for DBHS protein polymerization, complementing known interfaces.
- Understanding these interactions provides insights into paraspeckle assembly and SFPQ's roles.
- This knowledge can inform future therapeutic strategies for DBHS family-related diseases.
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