SPLIT: Stable Protein Coacervation Using a Light Induced Transition

ACS Synth Biol. 2020 Mar 20;9(3):500-507. doi: 10.1021/acssynbio.9b00503. Epub 2020 Feb 28.


Protein coacervates serve as hubs to concentrate and sequester proteins and nucleotides and thus function as membraneless organelles to manipulate cell physiology. We have engineered a coacervating protein to create tunable, synthetic membraneless organelles that assemble in response to a single pulse of light. Coacervation is driven by the intrinsically disordered RGG domain from the protein LAF-1, and opto-responsiveness is coded by the protein PhoCl, which cleaves in response to 405 nm light. We developed a fusion protein containing a solubilizing maltose-binding protein domain, PhoCl, and two copies of the RGG domain. Several seconds of illumination at 405 nm is sufficient to cleave PhoCl, removing the solubilization domain and enabling RGG-driven coacervation within minutes in cellular-sized water-in-oil emulsions. An optimized version of this system displayed light-induced coacervation in Saccharomyces cerevisiae. The methods described here provide novel strategies for inducing protein phase separation using light.

Keywords: PhoCl; RGG; biomolecular condensates; membraneless organelles; optogenetics; recombinant proteins.

Publication types

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

MeSH terms

  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism
  • Escherichia coli / genetics
  • Light
  • Maltose-Binding Proteins / genetics
  • Maltose-Binding Proteins / metabolism
  • Protein Domains
  • Protein Engineering / methods*
  • Protein Folding
  • RNA Helicases / genetics
  • RNA Helicases / metabolism
  • Recombinant Fusion Proteins / chemistry*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism


  • Caenorhabditis elegans Proteins
  • Maltose-Binding Proteins
  • Recombinant Fusion Proteins
  • RNA Helicases
  • laf-1 protein, C elegans