scholarly journals ATP regulates TDP-43 pathogenesis by specifically binding to an inhibitory component of a delicate network controlling LLPS

2020 ◽  
Author(s):  
Dang Mei ◽  
Liangzhong Lim ◽  
Jian Kang ◽  
Jianxing Song
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Neuron Death ◽  
Physiological Conditions ◽  
Intrinsically Disordered ◽  
Physicochemical Features ◽  
First Time ◽  
Inhibitory Interactions ◽  
Liquid Liquid Phase Separation

ABSTRACTVery recently, liquid-liquid phase separation (LLPS) of cytoplasmic TDP-43 independent of forming stress granule (SG) has been decoded to initiate the neuron death for ALS. Mysteriously neurons maintain ATP concentrations of ∼3 mM, but whether ATP modulates TDP-43 LLPS remains completely unknown. Here we characterized the effects of ATP on LLPS of TDP-43 PLD and its six mutants by DIC and NMR. For the first time, the results revealed: 1) ATP does induce and subsequently dissolve LLPS of TDP-43 PLD. 2) ATP achieves the modulation all by specifically binding Arg mostly saturated at 1:100. 3) LLPS of TDP-43 PLD and its exaggeration into aggregation are controlled by a delicate network composed of both attractive and inhibitory interactions, thus rationalizing the susceptibility of TDP-43 PLD to various ALS-causing mutations. Our studies together establish that ATP specifically binds Arg in intrinsically-disordered domains even not RGG-/R-rich, implying that ATP might be a universal regulator for most, if not all, R-containing intrinsically-disordered domains by altering their physicochemical features, conformations, dynamics, LLPS and assembly. Under physiological conditions, TDP-43 even in neuronal cytoplasm is highly bound with ATP and thus inhibited for its toxic LLPS, highlighting a central role of ATP in TDP-43 pathogenesis and aging.

Quadruplex Folding of DNA Promotes the Condensation of Linker Histones via Liquid-Liquid Phase Separation

2020 ◽  
Author(s):  
Masahiro Mimura ◽  
Shunsuke Tomita ◽  
Yoichi Shinkai ◽  
Kentaro Shiraki ◽  
Ryoji Kurita
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Electrostatic Interactions ◽  
Droplet Formation ◽  
Liquid Phase Separation ◽  
Intrinsically Disordered ◽  
G Quadruplex ◽  
Dna Quadruplex ◽  
Liquid Liquid Phase Separation

<p>Liquid-liquid phase separation (LLPS) of proteins and DNA has recently emerged as a possible mechanism underlying the dynamic organization of chromatin. We herein report the role of DNA quadruplex folding in liquid droplet formation via LLPS induced by interactions between DNA and linker histone H1 (H1), a key regulator of chromatin organization. Fluidity measurements inside the droplets and binding assays using G-quadruplex-selective probes demonstrated that quadruplex DNA structures, such as the G-quadruplex and i-motif, promote droplet formation with H1 and decrease molecular motility within droplets. The dissolution of the droplets in the presence of additives indicated that in addition to electrostatic interactions between the DNA and the intrinsically disordered region of H1, π-π stacking between quadruplex DNAs could potentially drive droplet formation. Given that DNA quadruplex structures are well documented in heterochromatin regions, it is imperative to understand the role of DNA quadruplex folding in the context of intranuclear LLPS.<b></b></p>

scholarly journals Quadruplex Folding of DNA Promotes the Condensation of Linker Histones via Liquid-Liquid Phase Separation

2020 ◽  
Author(s):  
Masahiro Mimura ◽  
Shunsuke Tomita ◽  
Yoichi Shinkai ◽  
Kentaro Shiraki ◽  
Ryoji Kurita
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Electrostatic Interactions ◽  
Droplet Formation ◽  
Liquid Phase Separation ◽  
Intrinsically Disordered ◽  
G Quadruplex ◽  
Dna Quadruplex ◽  
Liquid Liquid Phase Separation

<p>Liquid-liquid phase separation (LLPS) of proteins and DNA has recently emerged as a possible mechanism underlying the dynamic organization of chromatin. We herein report the role of DNA quadruplex folding in liquid droplet formation via LLPS induced by interactions between DNA and linker histone H1 (H1), a key regulator of chromatin organization. Fluidity measurements inside the droplets and binding assays using G-quadruplex-selective probes demonstrated that quadruplex DNA structures, such as the G-quadruplex and i-motif, promote droplet formation with H1 and decrease molecular motility within droplets. The dissolution of the droplets in the presence of additives indicated that in addition to electrostatic interactions between the DNA and the intrinsically disordered region of H1, π-π stacking between quadruplex DNAs could potentially drive droplet formation. Given that DNA quadruplex structures are well documented in heterochromatin regions, it is imperative to understand the role of DNA quadruplex folding in the context of intranuclear LLPS.<b></b></p>

Quadruplex Folding of DNA Promotes the Condensation of Linker Histones via Liquid-Liquid Phase Separation

2020 ◽  
Author(s):  
Masahiro Mimura ◽  
Shunsuke Tomita ◽  
Yoichi Shinkai ◽  
Kentaro Shiraki ◽  
Ryoji Kurita
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Electrostatic Interactions ◽  
Droplet Formation ◽  
Liquid Phase Separation ◽  
Intrinsically Disordered ◽  
G Quadruplex ◽  
Dna Quadruplex ◽  
Liquid Liquid Phase Separation

<p>Liquid-liquid phase separation (LLPS) of proteins and DNA has recently emerged as a possible mechanism underlying the dynamic organization of chromatin. We herein report the role of DNA quadruplex folding in liquid droplet formation via LLPS induced by interactions between DNA and linker histone H1 (H1), a key regulator of chromatin organization. Fluidity measurements inside the droplets and binding assays using G-quadruplex-selective probes demonstrated that quadruplex DNA structures, such as the G-quadruplex and i-motif, promote droplet formation with H1 and decrease molecular motility within droplets. The dissolution of the droplets in the presence of additives indicated that in addition to electrostatic interactions between the DNA and the intrinsically disordered region of H1, π-π stacking between quadruplex DNAs could potentially drive droplet formation. Given that DNA quadruplex structures are well documented in heterochromatin regions, it is imperative to understand the role of DNA quadruplex folding in the context of intranuclear LLPS.<b></b></p>

scholarly journals Quadruplex folding promotes the condensation of linker histones and DNAs via liquid-liquid phase separation

2021 ◽  
Author(s):  
Masahiro Mimura ◽  
Shunsuke Tomita ◽  
Yoichi Shinkai ◽  
Takuya Hosokai ◽  
Hiroyuki Kumeta ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Electrostatic Interactions ◽  
Droplet Formation ◽  
Liquid Phase Separation ◽  
Intrinsically Disordered ◽  
G Quadruplex ◽  
Dna Quadruplex ◽  
Liquid Liquid Phase Separation

Liquid-liquid phase separation (LLPS) of proteins and DNA has recently emerged as a possible mechanism underlying the dynamic organization of chromatin. We herein report the role of DNA quadruplex folding in liquid droplet formation via LLPS induced by interactions between DNA and linker histone H1 (H1), a key regulator of chromatin organization. <a>Fluidity measurements inside the droplets, binding assays using G-quadruplex-selective probes, and structural analyses based on circular dichroism demonstrated that quadruplex DNA structures, such as the G-quadruplex and i-motif, promote droplet formation with H1 and decrease molecular motility within droplets. </a><a></a><a></a><a>The dissolution of the droplets in the presence of additives and the LLPS of the DNA structural units indicated that in addition to electrostatic interactions between the DNA and the intrinsically disordered region of H1, π-π stacking between quadruplex DNAs could potentially drive droplet formation, unlike in the electrostatically driven LLPS of duplex DNA and H1. According to phase diagrams of anionic molecules with various conformations, the high LLPS ability associated with quadruplex folding arises from the formation of interfaces consisting of organized planes of guanine bases and the side surfaces with high charge density. </a>Given that DNA quadruplex structures are well documented in heterochromatin regions, it is imperative to understand the role of DNA quadruplex folding in the context of intranuclear LLPS.<br>

scholarly journals Does liquid–liquid phase separation drive peptide folding?

2021 ◽  
Author(s):  
Dean N. Edun ◽  
Meredith R. Flanagan ◽  
Arnaldo L. Serrano
Keyword(s):  
Infrared Spectroscopy ◽  
Phase Separation ◽  
Liquid Phase ◽  
Model Membrane ◽  
Peptide Folding ◽  
Two Dimensional ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Peptide ◽  
Two Dimensional Infrared Spectroscopy ◽  
Liquid Liquid Phase Separation

Two-dimensional infrared spectroscopy reveals folding of an intrinsically disordered peptide when sequestered into a model “membrane-less” organelle.

scholarly journals Deciphering the Role of π-Interactions in Polyelectrolyte Complexes Using Rationally Designed Peptides

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2074
Author(s):  
Sara Tabandeh ◽  
Cristina Elisabeth Lemus ◽  
Lorraine Leon
Keyword(s):  
Hydrogen Bonding ◽  
Phase Separation ◽  
Liquid Phase ◽  
Charge Density ◽  
Secondary Structures ◽  
Liquid Phase Separation ◽  
Polyelectrolyte Complexes ◽  
Π Interactions ◽  
Liquid Liquid Phase Separation

Electrostatic interactions, and specifically π-interactions play a significant role in the liquid-liquid phase separation of proteins and formation of membraneless organelles/or biological condensates. Sequence patterning of peptides allows creating protein-like structures and controlling the chemistry and interactions of the mimetic molecules. A library of oppositely charged polypeptides was designed and synthesized to investigate the role of π-interactions on phase separation and secondary structures of polyelectrolyte complexes. Phenylalanine was chosen as the π-containing residue and was used together with lysine or glutamic acid in the design of positively or negatively charged sequences. The effect of charge density and also the substitution of fluorine on the phenylalanine ring, known to disrupt π-interactions, were investigated. Characterization analysis using MALDI-TOF mass spectroscopy, H NMR, and circular dichroism (CD) confirmed the molecular structure and chiral pattern of peptide sequences. Despite an alternating sequence of chirality previously shown to promote liquid-liquid phase separation, complexes appeared as solid precipitates, suggesting strong interactions between the sequence pairs. The secondary structures of sequence pairs showed the formation of hydrogen-bonded structures with a β-sheet signal in FTIR spectroscopy. The presence of fluorine decreased hydrogen bonding due to its inhibitory effect on π-interactions. π-interactions resulted in enhanced stability of complexes against salt, and higher critical salt concentrations for complexes with more π-containing amino acids. Furthermore, UV-vis spectroscopy showed that sequences containing π-interactions and increased charge density encapsulated a small charged molecule with π-bonds with high efficiency. These findings highlight the interplay between ionic, hydrophobic, hydrogen bonding, and π-interactions in polyelectrolyte complex formation and enhance our understanding of phase separation phenomena in protein-like structures.

scholarly journals G-quadruplex DNA inhibits unwinding activity but promotes liquid–liquid phase separation by the DEAD-box helicase Ded1p

2021 ◽  
Author(s):  
Jun Gao ◽  
Zhaofeng Gao ◽  
Andrea A. Putnam ◽  
Alicia K. Byrd ◽  
Sarah L. Venus ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Intrinsically Disordered ◽  
Dead Box ◽  
G4 Dna ◽  
G Quadruplex ◽  
The Dead ◽  
Liquid Liquid Phase Separation

G-quadruplex (G4) DNA inhibits RNA unwinding activity but promotes liquid–liquid phase separation of the DEAD-box helicase Ded1p in vitro and in cells. This highlights multifaceted effects of G4DNA on an enzyme with intrinsically disordered domains.

scholarly journals Liquid–liquid phase separation in human health and diseases

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Bin Wang ◽  
Lei Zhang ◽  
Tong Dai ◽  
Ziran Qin ◽  
Huasong Lu ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Human Health ◽  
Essential Role ◽  
Current Knowledge ◽  
Vital Role ◽  
Liquid Phase Separation ◽  
Eukaryotic Cells ◽  
Liquid Liquid Phase Separation

AbstractEmerging evidence suggests that liquid–liquid phase separation (LLPS) represents a vital and ubiquitous phenomenon underlying the formation of membraneless organelles in eukaryotic cells (also known as biomolecular condensates or droplets). Recent studies have revealed evidences that indicate that LLPS plays a vital role in human health and diseases. In this review, we describe our current understanding of LLPS and summarize its physiological functions. We further describe the role of LLPS in the development of human diseases. Additionally, we review the recently developed methods for studying LLPS. Although LLPS research is in its infancy—but is fast-growing—it is clear that LLPS plays an essential role in the development of pathophysiological conditions. This highlights the need for an overview of the recent advances in the field to translate our current knowledge regarding LLPS into therapeutic discoveries.

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