Phase transition of a disordered nuage protein generates environmentally responsive membraneless organelles.
Cells chemically isolate molecules in compartments to both facilitate and regulate their interactions. In addition to membrane-encapsulated compartments, cells can form proteinaceous and membraneless organelles, including nucleoli, Cajal and PML bodies, and stress granules. The principles that determine when and why these structures form have remained elusive. Here, we demonstrate that the disordered tails of Ddx4, a primary constituent of nuage or germ granules, form phase-separated organelles both in live cells and in vitro. These bodies are stabilized by patterned electrostatic interactions that are highly sensitive to temperature, ionic strength, arginine methylation, and splicing. Sequence determinants are used to identify proteins found in both membraneless organelles and cell adhesion. Moreover, the bodies provide an alternative solvent environment that can concentrate single-stranded DNA but largely exclude double-stranded DNA. We propose that phase separation of disordered proteins containing weakly interacting blocks is a general mechanism for forming regulated, membraneless organelles.
Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK.
Timothy J
TJ
Nott
Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada.
Evangelia
E
Petsalaki
Research Institute, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada.
Patrick
P
Farber
Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S 1A7, Canada.
Dylan
D
Jervis
Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada.
Eden
E
Fussner
Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, UK.
Anne
A
Plochowietz
Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, UK.
Timothy D
TD
Craggs
Research Institute, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
David P
DP
Bazett-Jones
Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada.
Tony
T
Pawson
Research Institute, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada. Electronic address: forman@sickkids.ca.
Julie D
JD
Forman-Kay
Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK. Electronic address: andrew.baldwin@chem.ox.ac.uk.
Andrew J
AJ
Baldwin
D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism; D003594:Cytoplasmic Granules / Q000737:chemistry* / Q000378:metabolism; D053487:DEAD-box RNA Helicases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008745:Methylation; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009154:Mutation; D015388:Organelles / Q000737:chemistry* / Q000378:metabolism; D009994:Osmolar Concentration; D044367:Phase Transition; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity; D059008:Time-Lapse Imaging; D044366:Transition Temperature
D008164:Luminescent Proteins; D004247:DNA; C498288:DDX4 protein, human; D053487:DEAD-box RNA Helicases