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Interplay between charge distribution and DNA in shaping HP1 paralog phase separation and localization
Tien M Phan1, Young C Kim2, Galia T Debelouchina3
1Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, United States.
Elife
|April 9, 2024
Summary
Differences in heterochromatin protein 1 (HP1) paralog behavior during liquid-liquid phase separation (LLPS) are driven by sequence features like net charge. DNA binding also impacts HP1 paralog condensate stability.
Area of Science:
- Molecular Biology
- Biophysics
- Computational Biology
Background:
- The heterochromatin protein 1 (HP1) family is essential for heterochromatin formation and function.
- Human HP1 proteins (HP1α, HP1β, HP1γ) share structural similarities but exhibit distinct liquid-liquid phase separation (LLPS) behaviors.
Purpose of the Study:
- To identify sequence features governing differential LLPS of HP1 paralogs.
- To investigate the role of DNA in HP1 paralog co-localization and condensate stability.
Main Methods:
- Coarse-grained molecular simulations were used to model HP1 paralog interactions.
- Analysis focused on sequence charge properties, domain contributions, and DNA competitive binding.
Main Results:
- Net charge and charge patterning along the sequence significantly influence HP1 paralog LLPS propensity.
- Both conserved folded and less-conserved disordered domains contribute to differential LLPS.
- DNA binding alters HP1 paralog condensate stability through competitive interactions.
Conclusions:
- Physicochemical properties of HP1 sequences dictate their distinct phase-separation behaviors.
- Understanding these interactions provides a molecular basis for HP1's role in chromatin organization.
- DNA plays a critical role in modulating HP1 paralog assembly and function.
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