scholarly journals Liquid droplet formation by HP1α suggests a role for phase separation in heterochromatin

Nature ◽  
2017 ◽  
Vol 547 (7662) ◽  
pp. 236-240 ◽  
Author(s):  
Adam G. Larson ◽  
Daniel Elnatan ◽  
Madeline M. Keenen ◽  
Michael J. Trnka ◽  
Jonathan B. Johnston ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Droplet ◽  
Droplet Formation

scholarly journals NBR1-mediated p62-liquid droplets enhance the Keap1-Nrf2 system

2019 ◽  
Author(s):  
Pablo Sánchez-Martín ◽  
Yu-shin Sou ◽  
Shun Kageyama ◽  
Masaaki Komatsu
Keyword(s):  
Oxidative Stress ◽  
Liquid Droplet ◽  
Brca1 Gene ◽  
Droplet Formation ◽  
Receptor Protein ◽  
Liquid Droplets ◽  
Nrf2 Pathway ◽  
Selective Degradation ◽  
System A ◽  
Nrf2 Activation

Abstractp62/SQSTM1 is a multivalent protein that has an ability to cause a liquid-liquid phase separation and serves as a receptor protein that participates in cargo isolation during selective autophagy. This protein is also involved in the non-canonical activation of the Keap1-Nrf2 system, a major oxidative stress response pathway. Here we show a role of Neighbor of BRCA1 gene 1 (NBR1), an autophagy receptor structurally similar to p62/SQSTM1, in the p62-liquid droplet formation and the Keap1-Nrf2 pathway. The overexpression of NBR1 blocked selective degradation of p62/SQSTM1 through autophagy and promoted the accumulation and phosphorylation of p62/SQSTM1 in liquid-like bodies, which is required for the activation of Nrf2. NBR1 was induced in response to oxidative stress, and then the p62-mediated Nrf2 activation was up-regulated. Conversely, loss of Nbr1 suppresses not only the formation of p62/SQSTM1-liquid droplets but also p62-dependent Nrf2 activation during oxidative stress. Taken together, our results show that NBR1 mediates p62/SQSTM1-liquid droplet formation to activate the Keap1-Nrf2 pathway.

scholarly journals Perturbation of liquid droplets of P-granule protein LAF-1 by the antimicrobial peptide LL-III

2020 ◽  
Vol 56 (78) ◽  
pp. 11577-11580
Author(s):  
Rosario Oliva ◽  
Sanjib K. Mukherjee ◽  
Zamira Fetahaj ◽  
Simone Möbitz ◽  
Roland Winter
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Droplet Formation ◽  
Liquid Phase Separation ◽  
Liquid Droplets ◽  
Cellular Organization ◽  
P Protein ◽  
Liquid Liquid Phase Separation

Protein/RNA droplet formation by liquid–liquid phase separation has emerged as a key mechanism for cellular organization. We show that binding of antimicrobial peptides such as LL-III can lead to loss of droplet function.

NUCLEAR MAGNETISM OF HELIUM-3 PRECIPITATES

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3368-3368
Author(s):  
V. A. SHVARTS ◽  
K. J. KLESS ◽  
N. MATSUNAGA ◽  
E. D. ADAMS ◽  
J. X. XIA ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Phase Separation ◽  
Liquid Droplet ◽  
Magnetic Ordering ◽  
Solid Sample ◽  
Nuclear Magnetism ◽  
Weiss Constant ◽  
Simultaneous Measurements ◽  
Helium 3 ◽  
Made In

Simultaneous measurements of magnetic susceptibility from 0.5 to 10 mK and pressure from 2.88 to 3.54 MPa have been made in 3He nanoclusters embedded in a 4He matrix, following phase separation. The susceptibility of the 3.54 MPa, all –solid sample behaves similarly to that of bulk 3He for v = 21.3 cm3/mole, with a Weiss constant θ = -250μK. For the 2.88 MPa, liquid-droplet sample, θ = 140μK, indicating a ferromagnetic tendency, similar to 2-D films at some coverages. At intermediate pressures, χ has a peak near 1.05 mK, but without a discontinuity. For all samples, χ had a solid-like contribution to the lowest temperatures. Magnetic ordering in nano-clusters appears to be different than the U2D2 phase of bulk 3He.

scholarly journals Liquid-liquid phase separation and liquid-to-solid transition mediate α-synuclein amyloid fibril containing hydrogel formation

2019 ◽  
Author(s):  
Soumik Ray ◽  
Nitu Singh ◽  
Satyaprakash Pandey ◽  
Rakesh Kumar ◽  
Laxmikant Gadhe ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Droplet ◽  
Liquid Phase Separation ◽  
Amyloid Formation ◽  
Liquid To Solid Transition ◽  
Phase Separation Behavior ◽  
Separation Behavior ◽  
Liquid Liquid Phase Separation

SUMMARYα-Synuclein (α-Syn) aggregation and amyloid formation is directly linked with Parkinson’s disease (PD) pathogenesis. However, the early events involved in this process remain unclear. Here, using in vitro reconstitution and cellular model, we show that liquid-liquid phase separation (LLPS) of α-Syn precedes its aggregation. In particular, in vitro generated α-Syn liquid-like droplets eventually undergo a liquid-to-solid transition and form amyloid-hydrogel containing oligomers and fibrillar species. Factors known to aggravate α-Syn aggregation such as low pH, phosphomimic substitution, and familial PD mutation also promote α-Syn LLPS and its subsequent maturation. We further demonstrate α-Syn liquid droplet formation in cells, under oxidative stress. These cellular α-Syn droplets eventually transform into perinuclear aggresomes, the process regulated by microtubules. The present work provides detailed insights into the phase separation behavior of natively unstructured α-Syn and its conversion to a disease-associated aggregated state, which is highly relevant in PD pathogenesis.

scholarly journals ENL initiates multivalent phase separation of the super elongation complex (SEC) in controlling rapid transcriptional activation

2020 ◽  
Vol 6 (14) ◽  
pp. eaay4858 ◽  
Author(s):  
Chenghao Guo ◽  
Zhuanzhuan Che ◽  
Junjie Yue ◽  
Peng Xie ◽  
Shaohua Hao ◽  
...  
Keyword(s):  
Phase Separation ◽  
Rna Polymerase Ii ◽  
Transcriptional Activation ◽  
Liquid Droplet ◽  
Critical Role ◽  
Elongation Factor ◽  
Elongation Complex ◽  
Intrinsically Disordered ◽  
Super Elongation Complex

Release of paused RNA polymerase II (Pol II) requires incorporation of the positive transcription elongation factor b (P-TEFb) into the super elongation complex (SEC), thus resulting in rapid yet synchronous transcriptional activation. However, the mechanism underlying dynamic transition of P-TEFb from inactive to active state remains unclear. Here, we found that the SEC components are able to compartmentalize and concentrate P-TEFb via liquid-liquid phase separation from the soluble inactive HEXIM1 containing the P-TEFb complex. Specifically, ENL or its intrinsically disordered region is sufficient to initiate the liquid droplet formation of SEC. AFF4 functions together with ENL in fluidizing SEC droplets. SEC droplets are fast and dynamically formed upon serum exposure and required for rapid transcriptional induction. We also found that the fusion of ENL with MLL can boost SEC phase separation. In summary, our results suggest a critical role of multivalent phase separation of SEC in controlling transcriptional pause release.

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 Liquid Droplet Formation and Facile Cytosolic Translocation of IgG in the Presence of Attenuated Cationic Amphiphilic Lytic Peptides

2021 ◽  
Author(s):  
Takahiro Iwata ◽  
Hisaaki Hirose ◽  
Kentarou Sakamoto ◽  
Yusuke Hirai ◽  
Jan Vincent V. Arafiles ◽  
...  
Keyword(s):  
Liquid Droplet ◽  
Droplet Formation ◽  
Lytic Peptides

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>

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