Multivalent Proteins Rapidly and Reversibly Phase-Separate upon Osmotic Cell Volume Change

Ameya P Jalihal; Sethuramasundaram Pitchiaya; Lanbo Xiao; Pushpinder Bawa; Xia Jiang; Karan Bedi; Abhijit Parolia; Marcin Cieslik; Mats Ljungman; Arul M Chinnaiyan; Nils G Walter

doi:10.1016/j.molcel.2020.08.004

Multivalent Proteins Rapidly and Reversibly Phase-Separate upon Osmotic Cell Volume Change

Mol Cell. 2020 Sep 17;79(6):978-990.e5. doi: 10.1016/j.molcel.2020.08.004. Epub 2020 Aug 27.

Authors

Affiliations

¹ Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA; Cell and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA.
² Michigan Center for Translational Pathology, University of Michigan Medical School, Ann Arbor, MI 48109-1055, USA; Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA; Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI 48109, USA. Electronic address: sethu@umich.edu.
³ Michigan Center for Translational Pathology, University of Michigan Medical School, Ann Arbor, MI 48109-1055, USA; Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA.
⁴ Michigan Center for Translational Pathology, University of Michigan Medical School, Ann Arbor, MI 48109-1055, USA.
⁵ Department of Radiation Oncology, University of Michigan, Ann Arbor, MI 48109, USA.
⁶ Michigan Center for Translational Pathology, University of Michigan Medical School, Ann Arbor, MI 48109-1055, USA; Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA.
⁷ Department of Radiation Oncology, University of Michigan, Ann Arbor, MI 48109, USA; Rogel Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA; Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI 48109, USA; Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109, USA.
⁸ Michigan Center for Translational Pathology, University of Michigan Medical School, Ann Arbor, MI 48109-1055, USA; Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA; Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Urology, University of Michigan, Ann Arbor, MI 48109, USA; Rogel Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA; Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI 48109, USA. Electronic address: arul@umich.edu.
⁹ Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA; Rogel Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA; Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI 48109, USA. Electronic address: nwalter@umich.edu.

Abstract

Processing bodies (PBs) and stress granules (SGs) are prominent examples of subcellular, membraneless compartments that are observed under physiological and stress conditions, respectively. We observe that the trimeric PB protein DCP1A rapidly (within ∼10 s) phase-separates in mammalian cells during hyperosmotic stress and dissolves upon isosmotic rescue (over ∼100 s) with minimal effect on cell viability even after multiple cycles of osmotic perturbation. Strikingly, this rapid intracellular hyperosmotic phase separation (HOPS) correlates with the degree of cell volume compression, distinct from SG assembly, and is exhibited broadly by homo-multimeric (valency ≥ 2) proteins across several cell types. Notably, HOPS sequesters pre-mRNA cleavage factor components from actively transcribing genomic loci, providing a mechanism for hyperosmolarity-induced global impairment of transcription termination. Our data suggest that the multimeric proteome rapidly responds to changes in hydration and molecular crowding, revealing an unexpected mode of globally programmed phase separation and sequestration.

Keywords: cell volume; hydration; hyperosmotic stress; molecular crowding; phase separation; processing bodies; protein multivalency; self-interaction; stress granules; stress response.

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

Animals
Cell Size
Cell Survival / genetics
Endoribonucleases / genetics*
Humans
Osmotic Pressure / physiology
Proteome / genetics
RNA Precursors / genetics*
Stress, Physiological / genetics*
Trans-Activators / genetics*
Transcription Termination, Genetic*

Substances

Proteome
RNA Precursors
Trans-Activators
Endoribonucleases
DCP1A protein, human

Abstract

Publication types

MeSH terms

Substances

Grants and funding