Biosynthesis of the Scrapie Prion Protein in Scrapie-Infected Cells

Taraboulos, Albert; Borchelt, David R.; Raeber, Alex J.; Avrahami, Dana; Prusiner, S. B.

doi:10.1007/978-3-662-02928-2_41

Cited by 55 publications

(118 citation statements)

References 8 publications

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“…Several cellular processes have been implicated in the process of prion infection, including the sorting of PrP into lipid rafts (25,26). Lipid rafts are cholesterol-rich microdomains of the plasma membrane with a variety of roles in cellular biochemistry and are purified from the cell lysate by limited solubilization, followed by sucrose density ultracentrifugation (16).…”

Section: Resultsmentioning

confidence: 99%

Conservation of a Glycine-rich Region in the Prion Protein Is Required for Uptake of Prion Infectivity

Harrison

Lawson

Coleman

et al. 2010

Journal of Biological Chemistry

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Prion diseases are associated with the misfolding of the endogenously expressed prion protein (designated PrP C ) into an abnormal isoform (PrP Sc ) that has infectious properties. The hydrophobic domain of PrP C is highly conserved and contains a series of glycine residues that show perfect conservation among all species, strongly suggesting it has functional and evolutionary significance. These glycine residues appear to form repeats of the GXXXG protein-protein interaction motif (two glycines separated by any three residues); the retention of these residues is significant and presumably relates to the functionality of PrP C . Mutagenesis studies demonstrate that minor alterations to this highly conserved region of PrP C drastically affect the ability of cells to uptake and replicate prion infection in both cell and animal bioassay. The localization and processing of mutant PrP C are not affected, although in vitro and in vivo studies demonstrate that this region is not essential for interaction with PrP Sc , suggesting these residues provide conformational flexibility. These data suggest that this region of PrP C is critical in the misfolding process and could serve as a novel, species-independent target for prion disease therapeutics.

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Section: Resultsmentioning

confidence: 99%

Conservation of a Glycine-rich Region in the Prion Protein Is Required for Uptake of Prion Infectivity

Harrison

Lawson

Coleman

et al. 2010

Journal of Biological Chemistry

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“…Rafts or CLDs enriched for PrP C and PrP Sc have been isolated by flotation gradients (15,16). Depletion of cholesterol from cultured cells was found to inhibit the formation of nascent PrP Sc (14).…”

Section: Discussionmentioning

confidence: 99%

Human prions and plasma lipoproteins

Safar

Wille

Geschwind

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Prions are composed solely of an alternatively folded isoform of the prion protein (PrP), designated PrP Sc . The polyoxometalate phosphotungstic acid has been used to separate PrP Sc from its precursor PrP C by selective precipitation; notably, native PrP Sc has not been solubilized by using nondenaturing detergents. Because of the similarities between PrP Sc and lipoproteins with respect to hydrophobicity and formation of phosphotungstic acid complexes, we asked whether these molecules are bound to each other in blood. Here we report that prions from the brains of patients with sporadic Creutzfeldt-Jakob disease (CJD) bind to very low-density (VLDL) and low-density (LDL) lipoproteins but not to high-density lipoproteins (HDL) or other plasma components, as demonstrated both by affinity assay and electron microscopy. Immunoassays demonstrated that apolipoprotein B (apoB), which is the major protein component of VLDL and LDL, bound PrP Sc through a highly cooperative process. Approximately 50% of the PrP Sc bound to LDL particles was released after exposure to 4 M guanidine hydrochloride at 80°C for 20 min. The apparent binding constants of native human (Hu) PrP Sc or denatured recombinant HuPrP(90 -231) for apoB and LDL ranged from 28 to 212 pM. Whether detection of PrP Sc in VLDL and LDL particles can be adapted into an antemortem diagnostic test for prions in the blood of humans, livestock, and free-ranging cervids remains to be determined. prion protein ͉ apolipoprotein B ͉ blood ͉ Creutzfeldt-Jakob disease P rions are composed solely of an alternatively folded isoform of the prion protein, designated PrP Sc . Despite numerous efforts to solubilize native PrP Sc , no procedure has been developed except for incorporation of the protein into liposomes (1, 2). The hydrophobic properties of PrP Sc not only have impeded biological investigations but also have prevented structural studies at atomic resolution.During the development of an immunoassay for PrP Sc that does not depend upon limited proteolysis to hydrolyze the precursor protein designated PrP C , we found that the Na salt of phosphotungstic acid (PTA) selectively complexes with PrP Sc (3). PTA is a water-soluble salt featuring the nearly spherical trianion [PW 12 O 14 ] 3Ϫ that belongs to a broad class of polynuclear transition metal-oxo complexes known as polyoxometalates (POMs; see ref. 4). Recently, two of us (J.G.S. and S.B.P.) investigated the mechanism of selective complex formation between Keggin-type POMs and PrP Sc using a series of POM analogues (5). The ability of POMs to complex with PrP Sc as well as lipoproteins (6) raised the possibility that these two hydrophobic proteins might copurify.We began by examining the distribution of human (Hu) PrP Sc in human plasma fractions spiked with sporadic CreutzfeldtJakob disease (sCJD) prions from human brain. CJD prions were found with very low-density lipoproteins (VLDL) and low-density lipoproteins (LDL) but not with high-density lipoproteins (HDL) or any other plasma component. In addition to b...

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“…PrP C is found in lipid rafts or caveolae (29), specialized membrane compartments that contain high levels of cholesterol and sphingomyelin (30). Since the formation of these lipid rafts is cholesterol-dependent (31), and drugs that affect cholesterol levels influence the formation of PrP res (8,18), it is possible that PAF may regulate the composition and hence the function of lipid rafts. In this respect it should be noted that PAF induces sphingomyelinase which itself has been shown to increase the formation of PrP res in ScN2a cells (32).…”

Section: Discussionmentioning

confidence: 99%