Prion protein (PrP) underlies a spectrum of diseases with no established treatment and devastating human and economic consequences. The """"""""protein-only"""""""" hypothesis postulates that an abnormal prion protein conformation (PrPSc) propagates itself in an autocatalytic manner by recruiting normal isoform of the same protein (PrPC) and, therefore, acts as a transmissible agent of disease. The reconstitution of PrPSc in vitro from synthetic components has been difficult to achieve despite many years of effort. These difficulties are attributed to the lack of reliable biochemical markers of prion infectivity and to our poor understanding of the physical properties that are essential for infectivity. During the previous funding period, we developed the first experimental procedure for cell-free conversion of full-length PrP into self-propagating amyloid fibrils;we described several pathways of PrP polymerization;we introduced the most comprehensive mechanism of PrP conversion;we also established several novel assays including an immunoconformational assay for probing conformation within a single PrP fibril or particle. In the present application, we propose to elucidate PrPSc ultrastructure and to establish a link between infectivity and physical property of prion fibrils. The first specific aim will elucidate the substructure of PrPSc using novel immunoconformational assay developed in our laboratory combined with high resolution Atomic Force Microscopy. The second specific aim will elucidate the ultrastructure of prion fibrils generated in vitro, and the third specific aim is designed to test a relationship between conformational properties of the in vitro generated fibrils and their intrinsic infectivity. Such knowledge should lay the foundation for development of sensitive antemortem diagnostics and efficient therapeutics for treating prion diseases.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Project (R01)
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Special Emphasis Panel (ZRG1-MDCN-E (02))
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Wong, May
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University of Maryland Baltimore
Anatomy/Cell Biology
Schools of Medicine
United States
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Srivastava, Saurabh; Katorcha, Elizaveta; Daus, Martin L et al. (2017) Sialylation Controls Prion Fate in Vivo. J Biol Chem 292:2359-2368
Katorcha, Elizaveta; Baskakov, Ilia V (2017) Analyses of N-linked glycans of PrPSc revealed predominantly 2,6-linked sialic acid residues. FEBS J 284:3727-3738
Baskakov, Ilia V (2017) Limited understanding of the functional diversity of N-linked glycans as a major gap of prion biology. Prion 11:82-88
Morales, Rodrigo; Hu, Ping Ping; Duran-Aniotz, Claudia et al. (2016) Strain-dependent profile of misfolded prion protein aggregates. Sci Rep 6:20526
Baskakov, Ilia V; Katorcha, Elizaveta (2016) Multifaceted Role of Sialylation in Prion Diseases. Front Neurosci 10:358
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Katorcha, Elizaveta; Srivastava, Saurabh; Klimova, Nina et al. (2016) Sialylation of Glycosylphosphatidylinositol (GPI) Anchors of Mammalian Prions Is Regulated in a Host-, Tissue-, and Cell-specific Manner. J Biol Chem 291:17009-19
Katorcha, Elizaveta; Daus, Martin L; Gonzalez-Montalban, Nuria et al. (2016) Reversible off and on switching of prion infectivity via removing and reinstalling prion sialylation. Sci Rep 6:33119
Katorcha, Elizaveta; Makarava, Natallia; Savtchenko, Regina et al. (2015) Sialylation of the prion protein glycans controls prion replication rate and glycoform ratio. Sci Rep 5:16912
Srivastava, Saurabh; Makarava, Natallia; Katorcha, Elizaveta et al. (2015) Post-conversion sialylation of prions in lymphoid tissues. Proc Natl Acad Sci U S A 112:E6654-62

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