scholarly journals Biodegradable zwitterionic nanoparticles with tunable UCST-type phase separation under physiological conditions

Nanoscale ◽  
2019 ◽  
Vol 11 (35) ◽  
pp. 16582-16591 ◽  
Author(s):  
Mattia Sponchioni ◽  
Paola Rodrigues Bassam ◽  
Davide Moscatelli ◽  
Paolo Arosio ◽  
Umberto Capasso Palmiero
Keyword(s):  
Phase Separation ◽  
Controlled Delivery ◽  
Physiological Conditions ◽  
Type Phase ◽  
Delivery Strategies

We report tunable biodegradable zwitterionic nanoparticles with UCST behavior under physiological conditions that can be used in controlled delivery strategies.

scholarly journals TIA1 potentiates tau phase separation and promotes generation of toxic oligomeric tau

2021 ◽  
Vol 118 (9) ◽  
pp. e2014188118
Author(s):  
Peter E. A. Ash ◽  
Shuwen Lei ◽  
Jenifer Shattuck ◽  
Samantha Boudeau ◽  
Yari Carlomagno ◽  
...  
Keyword(s):  
Phase Separation ◽  
Polyethylene Glycol ◽  
Stress Response ◽  
Tau Protein ◽  
Rna Binding ◽  
Biological Activities ◽  
Rna Binding Protein ◽  
Physiological Conditions ◽  
Tau Oligomers

Tau protein plays an important role in the biology of stress granules and in the stress response of neurons, but the nature of these biochemical interactions is not known. Here we show that the interaction of tau with RNA and the RNA binding protein TIA1 is sufficient to drive phase separation of tau at physiological concentrations, without the requirement for artificial crowding agents such as polyethylene glycol (PEG). We further show that phase separation of tau in the presence of RNA and TIA1 generates abundant tau oligomers. Prior studies indicate that recombinant tau readily forms oligomers and fibrils in vitro in the presence of polyanionic agents, including RNA, but the resulting tau aggregates are not particularly toxic. We discover that tau oligomers generated during copartitioning with TIA1 are significantly more toxic than tau aggregates generated by incubation with RNA alone or phase-separated tau complexes generated by incubation with artificial crowding agents. This pathway identifies a potentially important source for generation of toxic tau oligomers in tau-related neurodegenerative diseases. Our results also reveal a general principle that phase-separated RBP droplets provide a vehicle for coassortment of selected proteins. Tau selectively copartitions with TIA1 under physiological conditions, emphasizing the importance of TIA1 for tau biology. Other RBPs, such as G3BP1, are able to copartition with tau, but this happens only in the presence of crowding agents. This type of selective mixing might provide a basis through which membraneless organelles bring together functionally relevant proteins to promote particular biological activities.

scholarly journals Ionic polypeptide tags for protein phase separation

2019 ◽  
Vol 10 (9) ◽  
pp. 2700-2707 ◽  
Author(s):  
Rachel A. Kapelner ◽  
Allie C. Obermeyer
Keyword(s):  
Phase Separation ◽  
Globular Proteins ◽  
Complex Coacervation ◽  
Protein Activity ◽  
Physiological Conditions

Short ionic polypeptide tags were demonstrated to drive complex coacervation of globular proteins at physiological conditions while maintaining protein activity.

scholarly journals Phase Separation and Stability of L21-Type Phase in Co2(Cr1−xFex)(Ga1−yAly) Alloys

2006 ◽  
Vol 47 (1) ◽  
pp. 20-24 ◽  
Author(s):  
Kosei Kobayashi ◽  
Ryosuke Kainuma ◽  
Kiyohito Ishida
Keyword(s):  
Phase Separation ◽  
Type Phase

From LCST to UCST: the phase separation behaviour of thermo-responsive polysiloxanes with the solubility parameters of solvents

2017 ◽  
Vol 41 (5) ◽  
pp. 1997-2003 ◽  
Author(s):  
Shusheng Li ◽  
Linglong Feng ◽  
Hang Lu ◽  
Shengyu Feng
Keyword(s):  
Phase Separation ◽  
Michael Addition ◽  
Mixed Solvents ◽  
Solubility Parameters ◽  
Efficient Catalyst ◽  
Catalyst Free ◽  
Highly Efficient ◽  
Type Phase

Thermo-responsive polysiloxanes with tunable LCST- and UCST-type phase separation in mixed solvents were synthesised via a facile, highly efficient, catalyst-free aza-Michael addition of poly(aminopropylmethylsiloxane) to N-isopropylacrylamide.

Structural Study on the UCST-Type Phase Separation of Poly(N-isopropylacrylamide) in Ionic Liquid

2013 ◽  
Vol 46 (3) ◽  
pp. 1101-1106 ◽  
Author(s):  
Hanako Asai ◽  
Kenta Fujii ◽  
Takeshi Ueki ◽  
Shota Sawamura ◽  
Yutaro Nakamura ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Phase Separation ◽  
Structural Study ◽  
Type Phase

scholarly journals Liquid-liquid phase separation and fibrillization of tau are independent processes with overlapping conditions

2019 ◽  
Author(s):  
Yanxian Lin ◽  
Yann Fichou ◽  
Zhikai Zeng ◽  
Nicole Y. Hu ◽  
Songi Han
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Amyloid Aggregation ◽  
Physiological Conditions ◽  
Three Stages ◽  
Tau Aggregation ◽  
Kinetics Of ◽  
Liquid Liquid Phase Separation

AbstractAmyloid aggregation of the microtubule binding protein tau is a hallmark of Alzheimer’s disease and many other neurodegenerative diseases. Recently, tau has been found to undergo liquid-liquid phase separation (LLPS) near physiological conditions. Although LLPS and aggregation have been shown to simultaneously occur under certain common conditions, it remains to be seen whether tau LLPS promotes aggregation, or if they are two independent processes. In this study, we address this question by combining multiple biochemical and biophysical assays in vitro. We investigated the impacts of LLPS on tau aggregation at three stages: conformation of tau, kinetics of aggregation and fibril quantity. We showed that none of these properties are influenced directly by LLPS, while amyloid aggregation propensity of tau can be altered without affecting its LLPS behavior. LLPS and amyloid aggregation of tau occur under overlapping conditions of enhanced intermolecular interactions and localization, but are two independent processes.

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