Molecular interactions underlying liquid-liquid phase separation of the FUS low-complexity domain

Nat Struct Mol Biol. 2019 Jul;26(7):637-648. doi: 10.1038/s41594-019-0250-x. Epub 2019 Jul 1.


The low-complexity domain of the RNA-binding protein FUS (FUS LC) mediates liquid-liquid phase separation (LLPS), but the interactions between the repetitive SYGQ-rich sequence of FUS LC that stabilize the liquid phase are not known in detail. By combining NMR and Raman spectroscopy, mutagenesis, and molecular simulation, we demonstrate that heterogeneous interactions involving all residue types underlie LLPS of human FUS LC. We find no evidence that FUS LC adopts conformations with traditional secondary structure elements in the condensed phase; rather, it maintains conformational heterogeneity. We show that hydrogen bonding, π/sp2, and hydrophobic interactions all contribute to stabilizing LLPS of FUS LC. In addition to contributions from tyrosine residues, we find that glutamine residues also participate in contacts leading to LLPS of FUS LC. These results support a model in which FUS LC forms dynamic, multivalent interactions via multiple residue types and remains disordered in the densely packed liquid phase.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Humans
  • Hydrogen Bonding
  • Hydrophobic and Hydrophilic Interactions
  • Intrinsically Disordered Proteins / chemistry
  • Models, Molecular
  • Phase Transition
  • Protein Conformation
  • Protein Domains
  • Protein Structure, Secondary
  • RNA-Binding Protein FUS / chemistry*


  • FUS protein, human
  • Intrinsically Disordered Proteins
  • RNA-Binding Protein FUS