Related Experiment Video

Updated: Nov 18, 2025

Real-time Quaking-induced Conversion Assay for Detection of CWD Prions in Fecal Material
09:50

Real-time Quaking-induced Conversion Assay for Detection of CWD Prions in Fecal Material

Published on: September 29, 2017

14.1K

Liquid-liquid phase separation of full-length prion protein initiates conformational conversion in vitro

Hiroya Tange1, Daisuke Ishibashi2, Takehiro Nakagaki2

  • 1Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan; Department of Neuropsychiatry, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.

The Journal of Biological Chemistry
|February 5, 2021
PubMed

Insights

Prion protein (PrP) can convert into a disease-associated form (PrP-res) through liquid-liquid phase separation (LLPS). This process, independent of infectious prions, involves PrP self-assembly into amyloid structures.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Neuroscience

Background:

  • Prion diseases involve amyloid fibril accumulation.
  • Infectious prions (PrPSc) convert normal prion protein (PrPC) to protease K-resistant PrP-res.
  • The intermediate steps of PrP conversion remain largely unknown.

Purpose of the Study:

  • To investigate if recombinant prion protein (rPrP) can convert to PrP-res via liquid-liquid phase separation (LLPS) without PrPSc.
  • To elucidate the potential role of LLPS and phase transitions in prion formation.

Main Methods:

  • Utilized an aqueous two-phase system (polyethylene glycol and dextran) to induce LLPS of rPrP.
  • Employed fluorescence recovery after photobleaching to study liquid-solid phase transitions.
  • Confirmed amyloid formation and proteinase resistance using Western blotting, FTIR, and Congo red staining.

Main Results:

  • rPrP underwent LLPS at the interface of the two-phase system, but not under single-phase conditions.
  • A rapid liquid-solid phase transition was observed, forming aged rPrP-gels.
  • These gels acquired proteinase resistance and β-sheet structure characteristic of amyloid, confirmed by multiple assays.
  • The N-terminal region (aa 23-89) of rPrP and kosmotropic salts were essential for the conversion process.

Conclusions:

  • Liquid-liquid phase separation (LLPS) and subsequent liquid-solid phase transitions are potential intermediate steps in prion conversion.
  • This mechanism allows for the spontaneous formation of protease-resistant prion protein aggregates from recombinant PrP.
  • The findings suggest a novel pathway for prion formation independent of pre-existing infectious prions.
Keywords:
amyloidaqueous two-phase systemliquid–liquid phase separationliquid–solid phase transitionprion

More Related Videos

Assessing Transmissible Spongiform Encephalopathy Species Barriers with an In Vitro Prion Protein Conversion Assay11:41

Assessing Transmissible Spongiform Encephalopathy Species Barriers with an In Vitro Prion Protein Conversion Assay

Published on: March 10, 2015

8.0K
Isolation of Soluble and Insoluble PrP Oligomers in the Normal Human Brain11:29

Isolation of Soluble and Insoluble PrP Oligomers in the Normal Human Brain

Published on: October 3, 2012

11.0K

Related Concept Videos

Amyloid Fibrils03:03

Amyloid Fibrils

Amyloid fibrils are aggregates of misfolded proteins.  Under most circumstances, misfolded proteins are either refolded by chaperone proteins or degraded by the proteasome. However, in the case of a mutation or a disease, these proteins can accumulate to form large clusters and often further assemble to form elongated fibers, called fibrils. 
Amyloid deposits were observed as early as 1639 in the liver and the spleen.   In 1854, Rudolph Virchow performed iodine staining,...
11.1K
Protein Folding01:25

Protein Folding

Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to its biological function. Interactions between its constituent amino acids guide protein folding, and hence the protein structure is primarily dependent on its amino acid sequence.
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
10.1K