scholarly journals Phase separation of Axin organizes the β-catenin destruction complex

2021 ◽  
Vol 220 (4) ◽  
Author(s):  
Junxiu Nong ◽  
Kexin Kang ◽  
Qiaoni Shi ◽  
Xuechen Zhu ◽  
Qinghua Tao ◽  
...  
Keyword(s):  
Phase Separation ◽  
Glycogen Synthase ◽  
Adenomatous Polyposis ◽  
Compelling Evidence ◽  
Glycogen Synthase Kinase 3Β ◽  
Polyposis Coli ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Region ◽  
Liquid Liquid Phase Separation

In Wnt/β-catenin signaling, the β-catenin protein level is deliberately controlled by the assembly of the multiprotein β-catenin destruction complex composed of Axin, adenomatous polyposis coli (APC), glycogen synthase kinase 3β (GSK3β), casein kinase 1α (CK1α), and others. Here we provide compelling evidence that formation of the destruction complex is driven by protein liquid–liquid phase separation (LLPS) of Axin. An intrinsically disordered region in Axin plays an important role in driving its LLPS. Phase-separated Axin provides a scaffold for recruiting GSK3β, CK1α, and β-catenin. APC also undergoes LLPS in vitro and enhances the size and dynamics of Axin phase droplets. The LLPS-driven assembly of the destruction complex facilitates β-catenin phosphorylation by GSK3β and is critical for the regulation of β-catenin protein stability and thus Wnt/β-catenin signaling.

scholarly journals Multivalent tumor suppressor adenomatous polyposis coli promotes Axin biomolecular condensate formation and efficient β-catenin degradation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tie-Mei Li ◽  
Jing Ren ◽  
Dylan Husmann ◽  
John P. Coan ◽  
Or Gozani ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Adenomatous Polyposis Coli ◽  
Adenomatous Polyposis ◽  
Polyposis Coli ◽  
Intrinsically Disordered ◽  
High Efficient ◽  
Condensate Formation ◽  
Core Components ◽  
Liquid Liquid Phase Separation

Abstract The tumor suppressor adenomatous polyposis coli (APC) is frequently mutated in colorectal cancers. APC and Axin are core components of a destruction complex that scaffolds GSK3β and CK1 to earmark β-catenin for proteosomal degradation. Disruption of APC results in pathologic stabilization of β-catenin and oncogenesis. However, the molecular mechanism by which APC promotes β-catenin degradation is unclear. Here, we find that the intrinsically disordered region (IDR) of APC, which contains multiple β-catenin and Axin interacting sites, undergoes liquid–liquid phase separation (LLPS) in vitro. Expression of the APC IDR in colorectal cells promotes Axin puncta formation and β-catenin degradation. Our results support the model that multivalent interactions between APC and Axin drives the β-catenin destruction complex to form biomolecular condensates in cells, which concentrate key components to achieve high efficient degradation of β-catenin.

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 Polycomb Cbx2 Condensates Assemble through Phase Separation

2018 ◽  
Author(s):  
Roubina Tatavosian ◽  
Samantha Kent ◽  
Kyle Brown ◽  
Tingting Yao ◽  
Huy Nguyen Duc ◽  
...  
Keyword(s):  
Phase Separation ◽  
Polycomb Group ◽  
Developmental Defects ◽  
Intrinsically Disordered ◽  
Condensate Formation ◽  
Development And Differentiation ◽  
Polycomb Repressive Complex 1 ◽  
Liquid Liquid Phase Separation

AbstractPolycomb group (PcG) proteins are master regulators of development and differentiation. Mutation and dysregulation of PcG genes cause developmental defects and cancer. PcG proteins form condensates in the nucleus of cells and these condensates are the physical sites of PcG-targeted gene silencing. However, the physiochemical principles underlying the PcG condensate formation remain unknown. Here we show that Polycomb repressive complex 1 (PRC1) protein Cbx2, one member of the Cbx family proteins, contains a long stretch of intrinsically disordered region (IDR). Cbx2 undergoes phase separation to form condensates. Cbx2 condensates exhibit liquid-like properties and can concentrate DNA and nucleosomes. We demonstrate that the conserved residues within the IDR promote the condensate formation in vitro and in vivo. We further indicate that H3K27me3 has minimal effects on the Cbx2 condensate formation while depletion of core PRC1 subunits facilitates the condensate formation. Thus, our results reveal that PcG condensates assemble through liquid-liquid phase separation (LLPS) and suggest that PcG-bound chromatin is in part organized through phase-separated condensates.

scholarly journals Phase separation of Nur77 mediates celastrol-induced mitophagy by promoting the liquidity of p62/SQSTM1 condensates

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shuang-zhou Peng ◽  
Xiao-hui Chen ◽  
Si-jie Chen ◽  
Jie Zhang ◽  
Chuan-ying Wang ◽  
...  
Keyword(s):  
Phase Separation ◽  
Cellular Functions ◽  
Intrinsically Disordered ◽  
Mechanistic Insight ◽  
Intrinsically Disordered Region ◽  
Uba Domain ◽  
Pb1 Domain ◽  
Additional Interaction ◽  
Insight Into ◽  
Liquid Liquid Phase Separation

AbstractLiquid-liquid phase separation promotes the formation of membraneless condensates that mediate diverse cellular functions, including autophagy of misfolded proteins. However, how phase separation participates in autophagy of dysfunctional mitochondria (mitophagy) remains obscure. We previously discovered that nuclear receptor Nur77 (also called TR3, NGFI-B, or NR4A1) translocates from the nucleus to mitochondria to mediate celastrol-induced mitophagy through interaction with p62/SQSTM1. Here, we show that the ubiquitinated mitochondrial Nur77 forms membraneless condensates capable of sequestrating damaged mitochondria by interacting with the UBA domain of p62/SQSTM1. However, tethering clustered mitochondria to the autophagy machinery requires an additional interaction mediated by the N-terminal intrinsically disordered region (IDR) of Nur77 and the N-terminal PB1 domain of p62/SQSTM1, which confers Nur77-p62/SQSTM1 condensates with the magnitude and liquidity. Our results demonstrate how composite multivalent interaction between Nur77 and p62/SQSTM1 coordinates to sequester damaged mitochondria and to connect targeted cargo mitochondria for autophagy, providing mechanistic insight into mitophagy.

scholarly journals Measles virus nucleo- and phosphoproteins form liquid-like phase-separated compartments that promote nucleocapsid assembly

2020 ◽  
Vol 6 (14) ◽  
pp. eaaz7095 ◽  
Author(s):  
Serafima Guseva ◽  
Sigrid Milles ◽  
Malene Ringkjøbing Jensen ◽  
Nicola Salvi ◽  
Jean-Philippe Kleman ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Measles Virus ◽  
Weak Interactions ◽  
Intrinsically Disordered ◽  
Infected Cells ◽  
Cellular Compartments ◽  
Liquid Liquid Phase Separation ◽  
Genomic Material

Many viruses are known to form cellular compartments, also called viral factories. Paramyxoviruses, including measles virus, colocalize their proteomic and genomic material in puncta in infected cells. We demonstrate that purified nucleoproteins (N) and phosphoproteins (P) of measles virus form liquid-like membraneless organelles upon mixing in vitro. We identify weak interactions involving intrinsically disordered domains of N and P that are implicated in this process, one of which is essential for phase separation. Fluorescence allows us to follow the modulation of the dynamics of N and P upon droplet formation, while NMR is used to investigate the thermodynamics of this process. RNA colocalizes to droplets, where it triggers assembly of N protomers into nucleocapsid-like particles that encapsidate the RNA. The rate of encapsidation within droplets is enhanced compared to the dilute phase, revealing one of the roles of liquid-liquid phase separation in measles virus replication.

scholarly journals The Ligand of Ate1 is intrinsically disordered and participates in nucleolar phase separation regulated by Jumonji Domain Containing 6

2020 ◽  
Vol 118 (1) ◽  
pp. e2015887118
Author(s):  
Akshaya Arva ◽  
Yasar Arfat T. Kasu ◽  
Jennifer Duncan ◽  
Mosleh A. Alkhatatbeh ◽  
Christopher S. Brower
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Protein Degradation ◽  
Unknown Function ◽  
Low Complexity ◽  
Bimolecular Fluorescence Complementation ◽  
Hydroxylase Activity ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Region ◽  
Liquid Liquid Phase Separation

The Ligand of Ate1 (Liat1) is a protein of unknown function that was originally discovered through its interaction with arginyl-tRNA protein transferase 1 (Ate1), a component of the Arg/N-degron pathway of protein degradation. Here, we characterized the functional domains of mouse Liat1 and found that its N-terminal half comprises an intrinsically disordered region (IDR) that facilitates its liquid–liquid phase separation (LLPS) in the nucleolus. Using bimolecular fluorescence complementation and immunocytochemistry, we found that Liat1 is targeted to the nucleolus by a low-complexity poly-K region within its IDR. We also found that the lysyl-hydroxylase activity of Jumonji Domain Containing 6 (Jmjd6) modifies Liat1, in a manner that requires the Liat1 poly-K region, and inhibits its nucleolar targeting and potential functions. In sum, this study reveals that Liat1 participates in nucleolar LLPS regulated by Jmjd6.

scholarly journals Thermodynamic and sequential characteristics of phase separation and droplet formation for an intrinsically disordered region/protein ensemble

2021 ◽  
Vol 17 (3) ◽  
pp. e1008672
Author(s):  
Wen-Ting Chu ◽  
Jin Wang
Keyword(s):  
Phase Separation ◽  
High Temperatures ◽  
Electrostatic Interactions ◽  
Sequence Length ◽  
Intrinsically Disordered ◽  
Dynamics Simulations ◽  
Conventional Behavior ◽  
Liquid Liquid Phase Separation

Liquid–liquid phase separation (LLPS) of some IDPs/IDRs can lead to the formation of the membraneless organelles in vitro and in vivo, which are essential for many biological processes in the cell. Here we select three different IDR segments of chaperon Swc5 and develop a polymeric slab model at the residue-level. By performing the molecular dynamics simulations, LLPS can be observed at low temperatures even without charge interactions and disappear at high temperatures. Both the sequence length and the charge pattern of the Swc5 segments can influence the critical temperature of LLPS. The results suggest that the effects of the electrostatic interactions on the LLPS behaviors can change significantly with the ratios and distributions of the charged residues, especially the sequence charge decoration (SCD) values. In addition, three different forms of swc conformation can be distinguished on the phase diagram, which is different from the conventional behavior of the free IDP/IDR. Both the packed form (the condensed-phase) and the dispersed form (the dilute-phase) of swc chains are found to be coexisted when LLPS occurs. They change to the fully-spread form at high temperatures. These findings will be helpful for the investigation of the IDP/IDR ensemble behaviors as well as the fundamental mechanism of the LLPS process in bio-systems.

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