Residue-by-Residue View of In Vitro FUS Granules that Bind the C-Terminal Domain of RNA Polymerase II

Mol Cell. 2015 Oct 15;60(2):231-41. doi: 10.1016/j.molcel.2015.09.006. Epub 2015 Oct 8.

Abstract

Phase-separated states of proteins underlie ribonucleoprotein (RNP) granules and nuclear RNA-binding protein assemblies that may nucleate protein inclusions associated with neurodegenerative diseases. We report that the N-terminal low-complexity domain of the RNA-binding protein Fused in Sarcoma (FUS LC) is structurally disordered and forms a liquid-like phase-separated state resembling RNP granules. This state directly binds the C-terminal domain of RNA polymerase II. Phase-separated FUS lacks static structures as probed by fluorescence microscopy, indicating they are distinct from both protein inclusions and hydrogels. We use solution nuclear magnetic resonance spectroscopy to directly probe the dynamic architecture within FUS liquid phase-separated assemblies. Importantly, we find that FUS LC retains disordered secondary structure even in the liquid phase-separated state. Therefore, we propose that disordered protein granules, even those made of aggregation-prone prion-like domains, are dynamic and disordered molecular assemblies with transiently formed protein-protein contacts.

Publication types

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

MeSH terms

  • Amino Acid Motifs
  • Binding Sites
  • Cytoplasmic Granules / chemistry*
  • Cytoplasmic Granules / metabolism
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression
  • Humans
  • Intrinsically Disordered Proteins / chemistry*
  • Intrinsically Disordered Proteins / genetics
  • Intrinsically Disordered Proteins / metabolism
  • Molecular Mimicry
  • Molecular Sequence Data
  • Phase Transition
  • Prions / chemistry
  • Prions / metabolism
  • Protein Binding
  • Protein Structure, Tertiary
  • RNA / chemistry*
  • RNA / metabolism
  • RNA Polymerase II / chemistry*
  • RNA Polymerase II / genetics
  • RNA Polymerase II / metabolism
  • RNA-Binding Protein FUS / chemistry*
  • RNA-Binding Protein FUS / genetics
  • RNA-Binding Protein FUS / metabolism
  • RNA-Binding Proteins / chemistry*
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Rheology

Substances

  • FUS protein, human
  • Intrinsically Disordered Proteins
  • Prions
  • RNA-Binding Protein FUS
  • RNA-Binding Proteins
  • Recombinant Proteins
  • RNA
  • RNA Polymerase II