The interplay between a GC-rich oligonucleotide and copper ions on prion protein conformational and phase transitions

Passos, Yulli M.; Amaral, Mariana J. do; Ferreira, Natalia; Macedo, Bruno; Chaves, Juliana A.P.; Oliveira, Vanessa E. de; Gomes, M. Teixeira; Silva, Jerson L.; Cordeiro, Yraima

doi:10.1016/j.ijbiomac.2021.01.097

Cited by 19 publications

(16 citation statements)

References 55 publications

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“…The ability of full-length PrP to form biomolecular condensates has been described recently ( 41 , 42 , 43 , 44 , 45 ); however, the underlying molecular mechanisms that drive the formation of liquid-like droplets remain unknown. In the present study, we analyzed phase separation of full-length PrP and its major proteolytic fragments N1, N2, C1, and C2.…”

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confidence: 99%

The N-terminal domain of the prion protein is required and sufficient for liquid–liquid phase separation: A crucial role of the Aβ-binding domain

Kamps

Lin

Oliva

et al. 2021

Journal of Biological Chemistry

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Formation of biomolecular condensates through liquid–liquid phase separation (LLPS) has been described for several pathogenic proteins linked to neurodegenerative diseases and is discussed as an early step in the formation of protein aggregates with neurotoxic properties. In prion diseases, neurodegeneration and formation of infectious prions is caused by aberrant folding of the cellular prion protein (PrP C ). PrP C is characterized by a large intrinsically disordered N-terminal domain and a structured C-terminal globular domain. A significant fraction of mature PrP C is proteolytically processed in vivo into an entirely unstructured fragment, designated N1, and the corresponding C-terminal fragment C1 harboring the globular domain. Notably, N1 contains a polybasic motif that serves as a binding site for neurotoxic Aβ oligomers. PrP can undergo LLPS; however, nothing is known how phase separation of PrP is triggered on a molecular scale. Here, we show that the intrinsically disordered N1 domain is necessary and sufficient for LLPS of PrP. Similar to full-length PrP, the N1 fragment formed highly dynamic liquid-like droplets. Remarkably, a slightly shorter unstructured fragment, designated N2, which lacks the Aβ-binding domain and is generated under stress conditions, failed to form liquid-like droplets and instead formed amorphous assemblies of irregular structures. Through a mutational analysis, we identified three positively charged lysines in the postoctarepeat region as essential drivers of condensate formation, presumably largely via cation–π interactions. These findings provide insights into the molecular basis of LLPS of the mammalian prion protein and reveal a crucial role of the Aβ-binding domain in this process.

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confidence: 99%

The N-terminal domain of the prion protein is required and sufficient for liquid–liquid phase separation: A crucial role of the Aβ-binding domain

Kamps

Lin

Oliva

et al. 2021

Journal of Biological Chemistry

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“…We also evaluated the effect of a 21-mer double-stranded and of a 25-mer single-stranded DNA oligonucleotide (D67 and A1, respectively), on PrP aggregation. A1 induced higher aggregation than D67, possibly due to differences in binding affinity and/or DNA conformation (Macedo et al, 2012;M. Passos et al, 2021).…”

Section: Discussionmentioning

confidence: 99%

Rabbit PrP Is Partially Resistant to in vitro Aggregation Induced by Different Biological Cofactors

et al. 2021

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Prion diseases have been described in humans and other mammals, including sheep, goats, cattle, and deer. Since mice, hamsters, and cats are susceptible to prion infection, they are often used to study the mechanisms of prion infection and conversion. Mammals, such as horses and dogs, however, do not naturally contract the disease and are resistant to infection, while others, like rabbits, have exhibited low susceptibility. Infection involves the conversion of the cellular prion protein (PrPC) to the scrapie form (PrPSc), and several cofactors have already been identified as important adjuvants in this process, such as glycosaminoglycans (GAGs), lipids, and nucleic acids. The molecular mechanisms that determine transmissibility between species remain unclear, as well as the barriers to transmission. In this study, we examine the interaction of recombinant rabbit PrPC (RaPrP) with different biological cofactors such as GAGs (heparin and dermatan sulfate), phosphatidic acid, and DNA oligonucleotides (A1 and D67) to evaluate the importance of these cofactors in modulating the aggregation of rabbit PrP and explain the animal’s different degrees of resistance to infection. We used spectroscopic and chromatographic approaches to evaluate the interaction with cofactors and their effect on RaPrP aggregation, which we compared with murine PrP (MuPrP). Our data show that all cofactors induce RaPrP aggregation and exhibit pH dependence. However, RaPrP aggregated to a lesser extent than MuPrP in the presence of any of the cofactors tested. The binding affinity with cofactors does not correlate with these low levels of aggregation, suggesting that the latter are related to the stability of PrP at acidic pH. The absence of the N-terminus affected the interaction with cofactors, influencing the efficiency of aggregation. These findings demonstrate that the interaction with polyanionic cofactors is related to rabbit PrP being less susceptible to aggregation in vitro and that the N-terminal domain is important to the efficiency of conversion, increasing the interaction with cofactors. The decreased effect of cofactors in rabbit PrP likely explains its lower propensity to prion conversion.

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“…Binding of copper (Cu(II), Cu 2+ ) to PrP C facilitates redox balance and copper homeostasis [ 289 ] both of which are often disturbed in the TME where cancer drug resistance is associated with higher serum copper levels in patients compared to healthy controls or patients who responded to chemotherapy [ 290 , 291 ]. Copper also changes the conformation of the N-terminal domain [ 292 , 293 , 294 , 295 ], which may impede LLPS [ 121 , 296 ] or even prevent the formation of straight β-strands backbone structures in the infectious PrP Sc form when bound to the non-octarepeat peptides (residues 92–96) [ 297 , 298 ]. However, the Cu 2+ inhibition of amyloid formation is dependent upon binding capacity that becomes less effective at a lower pH [ 93 , 299 ], which is characteristic of most TMEs.…”

Section: Liquid–liquid Phase Separation May Regulate Prion Conversion...mentioning

confidence: 99%

Melatonin: Regulation of Prion Protein Phase Separation in Cancer Multidrug Resistance

Loh¹,

Reíter

2022

Molecules

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The unique ability to adapt and thrive in inhospitable, stressful tumor microenvironments (TME) also renders cancer cells resistant to traditional chemotherapeutic treatments and/or novel pharmaceuticals. Cancer cells exhibit extensive metabolic alterations involving hypoxia, accelerated glycolysis, oxidative stress, and increased extracellular ATP that may activate ancient, conserved prion adaptive response strategies that exacerbate multidrug resistance (MDR) by exploiting cellular stress to increase cancer metastatic potential and stemness, balance proliferation and differentiation, and amplify resistance to apoptosis. The regulation of prions in MDR is further complicated by important, putative physiological functions of ligand-binding and signal transduction. Melatonin is capable of both enhancing physiological functions and inhibiting oncogenic properties of prion proteins. Through regulation of phase separation of the prion N-terminal domain which targets and interacts with lipid rafts, melatonin may prevent conformational changes that can result in aggregation and/or conversion to pathological, infectious isoforms. As a cancer therapy adjuvant, melatonin could modulate TME oxidative stress levels and hypoxia, reverse pH gradient changes, reduce lipid peroxidation, and protect lipid raft compositions to suppress prion-mediated, non-Mendelian, heritable, but often reversible epigenetic adaptations that facilitate cancer heterogeneity, stemness, metastasis, and drug resistance. This review examines some of the mechanisms that may balance physiological and pathological effects of prions and prion-like proteins achieved through the synergistic use of melatonin to ameliorate MDR, which remains a challenge in cancer treatment.

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The interplay between a GC-rich oligonucleotide and copper ions on prion protein conformational and phase transitions

Cited by 19 publications

References 55 publications

The N-terminal domain of the prion protein is required and sufficient for liquid–liquid phase separation: A crucial role of the Aβ-binding domain

The N-terminal domain of the prion protein is required and sufficient for liquid–liquid phase separation: A crucial role of the Aβ-binding domain

Rabbit PrP Is Partially Resistant to in vitro Aggregation Induced by Different Biological Cofactors

Melatonin: Regulation of Prion Protein Phase Separation in Cancer Multidrug Resistance

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