Liquid‐liquid phase separation and fibrillation of the prion protein modulated by a high‐affinity DNA aptamer

2019 ◽  
Vol 34 (1) ◽  
pp. 365-385 ◽  
Author(s):  
Carolina O. Matos ◽  
Yulli M. Passos ◽  
Mariana J. Amaral ◽  
Bruno Macedo ◽  
Matheus H. Tempone ◽  
...  
2019 ◽  
Author(s):  
Carolina O. Matos ◽  
Yulli M. Passos ◽  
Mariana J. do Amaral ◽  
Bruno Macedo ◽  
Matheus Tempone ◽  
...  

ABSTRACTStructural conversion of cellular prion protein (PrPC) into scrapie PrP (PrPSc) and subsequent aggregation are key events for the onset of Transmissible Spongiform Encephalopathies (TSEs). Experimental evidences support the role of nucleic acids (NAs) in assisting the protein conversion process. Here, we used the SELEX methodology to identify two 25-mer DNA aptamers against the globular domain of recombinant murine PrP (rPrP90-231), namely A1 and A2. High-affinity binding of A1 and A2 to rPrP was verified by ITC. Aptamers structure was characterized by theoretical predictions, CD, NMR and SAXS, revealing that A1 adopts a hairpin conformation. Aptamer binding caused dynamic aggregation of rPrP90-231, resulting from the ability of rPrP90-231to undergo liquid-liquid phase separation (LLPS). While free rPrP90-231phase separated into large droplets, aptamer binding increased the amount but reduced the size of the condensates. Strikingly, a modified A1 aptamer that does not adopt a hairpin structure induced transition to an ordered state, suggestive of amyloid formation on the surface of the droplets. Our results describe for the first time PrP:NA interaction leading to LLPS and modulation of this effect depending on NA structure and binding stoichiometry, shedding light on the role of NAs in PrP misfolding and TSEs.


2020 ◽  
Author(s):  
Hiroya Tange ◽  
Daisuke Ishibashi ◽  
Takehiro Nakagaki ◽  
Yuzuru Taguchi ◽  
Yuji O. Kamatari ◽  
...  

AbstractPrion diseases are characterized by accumulation of amyloid fibrils. The causative agent is an infectious amyloid that is comprised solely of misfolded prion protein (PrPSc). Prions can convert PrPC to proteinase-resistant PrP (PrP-res) in vitro; however, the intermediate steps involved in the spontaneous conversion remain unknown. We investigated whether recombinant prion protein (rPrP) can directly convert into PrP-res via liquid-liquid phase separation in the absence of PrPSc. We found that rPrP underwent liquid-liquid phase separation at the interface of the aqueous two-phase system (ATPS) of polyethylene glycol (PEG) and dextran, whereas single-phase conditions were not inducible. Fluorescence recovery assay after photobleaching revealed that the liquid-solid phase transition occurred within a short time. The aged rPrP-gel acquired proteinase-resistant amyloid accompanied by β-sheet conversion, as confirmed by western blotting, Fourier transform infrared spectroscopy, and Congo red staining. The reactions required both the N-terminal region of rPrP (amino acids 23-89) and kosmotropic salts, suggesting that the kosmotropic anions may interact with the N-terminal region of rPrP to promote liquid-liquid phase separation. Thus, structural conversion via liquid–liquid phase separation and liquid–solid phase transition are intermediate steps in the conversion of prions.


2021 ◽  
pp. 100367
Author(s):  
Hiroya Tange ◽  
Daisuke Ishibashi ◽  
Takehiro Nakagaki ◽  
Yuzuru Taguchi ◽  
Yuji O. Kamatari ◽  
...  

2021 ◽  
Vol 433 (2) ◽  
pp. 166731
Author(s):  
Yanxian Lin ◽  
Yann Fichou ◽  
Andrew P. Longhini ◽  
Luana C. Llanes ◽  
Pengyi Yin ◽  
...  

Author(s):  
Yanting Xing ◽  
Aparna Nandakumar ◽  
Aleksandr Kakinen ◽  
Yunxiang Sun ◽  
Thomas P. Davis ◽  
...  

2021 ◽  
Author(s):  
Kazuki Murakami ◽  
Shinji Kajimoto ◽  
Daiki Shibata ◽  
Kunisato Kuroi ◽  
Fumihiko Fujii ◽  
...  

Liquid–liquid phase separation (LLPS) plays an important role in a variety of biological processes and is also associated with protein aggregation in neurodegenerative diseases. Quantification of LLPS is necessary to...


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