The Glycosylation Status of PrP
            <sup>C</sup>
            Is a Key Factor in Determining Transmissible Spongiform Encephalopathy Transmission between Species

Wiseman, Frances K.; Cancellotti, Enrico; Piccardo, Pedro; Iremonger, Kayleigh; Boyle, Aileen; Brown, Deborah; Ironside, James W.; Manson, Jean; Diack, Abigail B.

doi:10.1128/jvi.02296-14

Cited by 50 publications

(43 citation statements)

References 58 publications

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“…The observation that in sFI (but not in sCJDMM2) the glycoform ratio of totPrP Sc is dominated by the di-glycosylated form and differs from that of resPrP Sc argues that, in sFI, senPrP Sc and resPrP Sc preferentially target different PrP C glycoforms for conversion2122232425. It has recently been proposed that the sialic acid moiety of the PrP C glycans impairs conversion to PrP Sc 24.…”

Section: Discussionmentioning

confidence: 99%

“…Alternatively, PrP C conversion to senPrP Sc might be less affected by sugar sialylation in sFI, or senPrP Sc and resPrP Sc glycoforms might have different turnovers. Regardless of the mechanism, the difference in glycoform ratios is significant considering the rising evidence that glycan representation, structure or both can affect strain characteristics212526.…”

Section: Discussionmentioning

confidence: 99%

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Novel strain properties distinguishing sporadic prion diseases sharing prion protein genotype and prion type

Cracco

Notari

Calì

et al. 2017

Sci Rep

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In most human sporadic prion diseases the phenotype is consistently associated with specific pairings of the genotype at codon 129 of the prion protein gene and conformational properties of the scrapie PrP (PrPSc) grossly identified types 1 and 2. This association suggests that the 129 genotype favours the selection of a distinct strain that in turn determines the phenotype. However, this mechanism cannot play a role in the phenotype determination of sporadic fatal insomnia (sFI) and a subtype of sporadic Creutzfeldt-Jakob disease (sCJD) identified as sCJDMM2, which share 129 MM genotype and PrPSc type 2 but are associated with quite distinct phenotypes. Our detailed comparative study of the PrPSc conformers has revealed major differences between the two diseases, which preferentially involve the PrPSc component that is sensitive to digestion with proteases (senPrPSc) and to a lesser extent the resistant component (resPrPSc). We conclude that these variations are consistent with two distinct strains in sFI and sCJDMM2, and that the rarer sFI is the result of a variant strain selection pathway that might be favoured by a different brain site of initial PrPSc formation in the two diseases.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Novel strain properties distinguishing sporadic prion diseases sharing prion protein genotype and prion type

Cracco

Notari

Calì

et al. 2017

Sci Rep

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“…In addition, glycosylation can affect efficiency of neuroinvasion after peripheral infection (33). Glycosylation was also found to influence cross-species interactions between PrPsen and PrPres during in vitro conversion reactions (34) as well as cross-species infection in vivo (35). The mechanisms of these effects are not clear, but glycosylation differences might act by altering protein folding or interactions of PrPres which might, in turn, influence further cycles of new PrPres generation.…”

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confidence: 99%

Increased Infectivity of Anchorless Mouse Scrapie Prions in Transgenic Mice Overexpressing Human Prion Protein

Race

Phillips

Meade-White

et al. 2015

J Virol

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Prion protein (PrP) is found in all mammals, mostly as a glycoprotein anchored to the plasma membrane by a C-terminal glycosylphosphatidylinositol (GPI) linkage. Following prion infection, host protease-sensitive prion protein (PrPsen or PrPC) is converted into an abnormal, disease-associated, protease-resistant form (PrPres). Biochemical characteristics, such as the PrP amino acid sequence, and posttranslational modifications, such as glycosylation and GPI anchoring, can affect the transmissibility of prions as well as the biochemical properties of the PrPres generated. Previous in vivo studies on the effects of GPI anchoring on prion infectivity have not examined cross-species transmission. In this study, we tested the effect of lack of GPI anchoring on a species barrier model using mice expressing human PrP. In this model, anchorless 22L prions derived from tg44 mice were more infectious than 22L prions derived from C57BL/10 mice when tested in tg66 transgenic mice, which expressed wild-type anchored human PrP at 8-to 16-fold above normal. Thus, the lack of the GPI anchor on the PrPres from tg44 mice appeared to reduce the effect of the mouse-human PrP species barrier. In contrast, neither source of prions induced disease in tgRM transgenic mice, which expressed human PrP at 2-to 4-fold above normal. IMPORTANCE Prion protein (PrP) is found in all mammals, usually attached to cells by an anchor molecule called GPI. Following prion infection, PrP is converted into a disease-associated form (PrPres). While most prion diseases are species specific, this finding is not consistent, and species barriers differ in strength. The amino acid sequence of PrP varies among species, and this variability affects prion species barriers. However, other PrP modifications, including glycosylation and GPI anchoring, may also influence cross-species infectivity. We studied the effect of PrP GPI anchoring using a mouse-to-human species barrier model. Experiments showed that prions produced by mice expressing only anchorless PrP were more infectious than prions produced in mice expressing anchored PrP. Thus, the lack of the GPI anchor on prions reduced the effect of the mouse-human species barrier. Our results suggest that prion diseases that produce higher levels of anchorless PrP may pose an increased risk for cross-species infection. P rion diseases, also known as transmissible spongiform encephalopathies (TSEs), are fatal neurodegenerative diseases that occur in many mammals, including humans. Central to all prion diseases is the conversion of the normal host prion protein (PrPsen or PrPC) into an abnormal, protease-resistant form (PrPres) associated with disease. In previous studies, PrPres and infectivity were generated concurrently in a cell-free in vitro system, proving that live cells were not required for formation of new prion infectivity in a cell-free in vitro system (1-4), a finding which supported the role of PrPres as the infectious prion agent (5). During the course of prion disease, repeated conversion of P...

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“…The addition of mature, complex N-linked sugars on PrP C is one indicator of proper folding and transport to the cell surface (52,56,67) and can influence conversion and TSE pathogenesis (68)(69)(70)(71)(72)(73)(74). In order to establish if WT and TM PrP were glycosylated similarly, lysates were treated with PNGase F, which cleaves N-linked oligosaccharides from glycoproteins (Fig.…”

Section: Resultsmentioning

confidence: 99%

PrP Knockout Cells Expressing Transmembrane PrP Resist Prion Infection

Marshall

Hughson

Vascellari

et al. 2017

J Virol

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Glycosylphosphatidylinositol (GPI) anchoring of the prion protein (PrP C ) influences PrP C misfolding into the disease-associated isoform, PrP res , as well as prion propagation and infectivity. GPI proteins are found in cholesterol-and sphingolipid-rich membrane regions called rafts. Exchanging the GPI anchor for a nonraft transmembrane sequence redirects PrP C away from rafts. Previous studies showed that nonraft transmembrane PrP C variants resist conversion to PrP res when transfected into scrapie-infected N2a neuroblastoma cells, likely due to segregation of transmembrane PrP C and GPI-anchored PrP res in distinct membrane environments. Thus, it remained unclear whether transmembrane PrP C might convert to PrP res if seeded by an exogenous source of PrP res not associated with host cell rafts and without the potential influence of endogenous expression of GPI-anchored PrP C . To further explore these questions, constructs containing either a C-terminal wild-type GPI anchor signal sequence or a nonraft transmembrane sequence containing a flexible linker were expressed in a cell line derived from PrP knockout hippocampal neurons, NpL2. NpL2 cells have physiological similarities to primary neurons, representing a novel and advantageous model for studying transmissible spongiform encephalopathy (TSE) infection. Cells were infected with inocula from multiple prion strains and in different biochemical states (i.e., membrane bound as in brain microsomes from wild-type mice or purified GPI-anchorless amyloid fibrils). Only GPI-anchored PrP C supported persistent PrP res propagation. Our data provide strong evidence that in cell culture GPI anchor-directed membrane association of PrP C is required for persistent PrP res propagation, implicating raft microdomains as a location for conversion.IMPORTANCE Mechanisms of prion propagation, and what makes them transmissible, are poorly understood. Glycosylphosphatidylinositol (GPI) membrane anchoring of the prion protein (PrP C ) directs it to specific regions of cell membranes called rafts. In order to test the importance of the raft environment on prion propagation, we developed a novel model for prion infection where cells expressing either GPI-anchored PrP C or transmembrane-anchored PrP C , which partitions it to a different location, were treated with infectious, misfolded forms of the prion protein, PrP res . We show that only GPI-anchored PrP C was able to convert to PrP res and able to serially propagate. The results strongly suggest that GPI anchoring and the localization of PrP C to rafts are crucial to the ability of PrP C to propagate as a prion.

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The Glycosylation Status of PrP ^C Is a Key Factor in Determining Transmissible Spongiform Encephalopathy Transmission between Species

Cited by 50 publications

References 58 publications

Novel strain properties distinguishing sporadic prion diseases sharing prion protein genotype and prion type

Novel strain properties distinguishing sporadic prion diseases sharing prion protein genotype and prion type

Increased Infectivity of Anchorless Mouse Scrapie Prions in Transgenic Mice Overexpressing Human Prion Protein

PrP Knockout Cells Expressing Transmembrane PrP Resist Prion Infection

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The Glycosylation Status of PrP C Is a Key Factor in Determining Transmissible Spongiform Encephalopathy Transmission between Species

Cited by 50 publications

References 58 publications

Novel strain properties distinguishing sporadic prion diseases sharing prion protein genotype and prion type

Novel strain properties distinguishing sporadic prion diseases sharing prion protein genotype and prion type

Increased Infectivity of Anchorless Mouse Scrapie Prions in Transgenic Mice Overexpressing Human Prion Protein

PrP Knockout Cells Expressing Transmembrane PrP Resist Prion Infection

Contact Info

Product

Resources

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The Glycosylation Status of PrP ^C Is a Key Factor in Determining Transmissible Spongiform Encephalopathy Transmission between Species