RNA-Induced Conformational Switching and Clustering of G3BP Drive Stress Granule Assembly by Condensation

  • Cell. 2020 Apr 16;181(2):346-361.e17. doi: 10.1016/j.cell.2020.03.049.
Jordina Guillén-Boixet  1 ,  Andrii Kopach  2 ,  Alex S Holehouse  3 ,  Sina Wittmann  2 ,  Marcus Jahnel  4 ,  Raimund Schlüßler  1 ,  Kyoohyun Kim  1 ,  Irmela R E A Trussina  1 ,  Jie Wang  2 ,  Daniel Mateju  2 ,  Ina Poser  2 ,  Shovamayee Maharana  1 ,  Martine Ruer-Gruß  2 ,  Doris Richter  1 ,  Xiaojie Zhang  5 ,  Young-Tae Chang  6 ,  Jochen Guck  1 ,  Alf Honigmann  2 ,  Julia Mahamid  5 ,  Anthony A Hyman  2 ,  Rohit V Pappu  7 ,  Simon Alberti  8 ,  Titus M Franzmann  1
Affiliations
  • 1. Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany.
  • 2. Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
  • 3. Department of Biomedical Engineering and Center for Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA; Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA.
  • 4. Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany; Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
  • 5. Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
  • 6. Center for Self-Assembly and Complexity, Institute for Basic Science, Pohang 37673, Republic of Korea; Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea.
  • 7. Department of Biomedical Engineering and Center for Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA.
  • 8. Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany; Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany. Electronic address: [email protected].
PMID: 32302572 DOI: 10.1016/j.cell.2020.03.049
Abstract

Stressed cells shut down translation, release mRNA molecules from polysomes, and form stress granules (SGs) via a network of interactions that involve G3BP. Here we focus on the mechanistic underpinnings of SG assembly. We show that, under non-stress conditions, G3BP adopts a compact auto-inhibited state stabilized by electrostatic intramolecular interactions between the intrinsically disordered acidic tracts and the positively charged arginine-rich region. Upon release from polysomes, unfolded mRNAs outcompete G3BP auto-inhibitory interactions, engendering a conformational transition that facilitates clustering of G3BP through protein-RNA interactions. Subsequent physical crosslinking of G3BP clusters drives RNA molecules into networked RNA/protein condensates. We show that G3BP condensates impede RNA entanglement and recruit additional client proteins that promote SG maturation or induce a liquid-to-solid transition that may underlie disease. We propose that condensation coupled to conformational rearrangements and heterotypic multivalent interactions may be a general principle underlying RNP granule assembly.

Keywords
G3BP; Neurodegenerative disease; RNP granules; liquid-to-solid transition; phase separation; stress granules; stress response.