The Effect of Disease-associated Mutations on the Folding Pathway of Human Prion Protein

Department of Chemistry, Case Western Reserve University, Cleveland, Ohio, United States
Journal of Biological Chemistry (Impact Factor: 4.57). 05/2004; 279(17):18008-14. DOI: 10.1074/jbc.M313581200
Source: PubMed


Propagation of transmissible spongiform encephalopathies is believed to involve the conversion of cellular prion protein,
PrPC, into a misfolded oligomeric form, PrPSc. An important step toward understanding the mechanism of this conversion is to elucidate the folding pathway(s) of the prion
protein. We reported recently (Apetri, A. C., and Surewicz, W. K. (2002) J. Biol. Chem. 277, 44589-44592) that the folding of wild-type prion protein can best be described by a three-state sequential model involving
a partially folded intermediate. Here we have performed kinetic stopped-flow studies for a number of recombinant prion protein
variants carrying mutations associated with familial forms of prion disease. Analysis of kinetic data clearly demonstrates
the presence of partially structured intermediates on the refolding pathway of each PrP variant studied. In each case, the
partially folded state is at least one order of magnitude more populated than the fully unfolded state. The present study
also reveals that, for the majority of PrP variants tested, mutations linked to familial prion diseases result in a pronounced
increase in the thermodynamic stability, and thus the population, of the folding intermediate. These data strongly suggest
that partially structured intermediates of PrP may play a crucial role in prion protein conversion, serving as direct precursors
of the pathogenic PrPSc isoform.

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    • "However, there is strong evidence to refute this hypothesis (Capellari et al., 2011). A mutant that strongly destabilizes PrP (F198S, Table 1) results in a late-onset, rather slowly developing PrD, whereas mutants causing moderate (D178N) or no (E200K) destabilization cause earlier and faster-progressing diseases (Apetri et al., 2004; Capellari et al., 2011; Kovács et al., 2002). Mutations also occur in the unstructured N-terminal region, including substitutions of prolines for leucines and increases or decreases in the size of an octapeptide repeat (Piccardo et al., 1998). "
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    ABSTRACT: The mechanisms underlying the selective targeting of specific brain regions by different neurodegenerative diseases is one of the most intriguing mysteries in medicine. For example, it is known that Alzheimer's disease primarily affects parts of the brain that play a role in memory, whereas Parkinson's disease predominantly affects parts of the brain that are involved in body movement. However, the reasons that other brain regions remain unaffected in these diseases are unknown. A better understanding of the phenomenon of selective vulnerability is required for the development of targeted therapeutic approaches that specifically protect affected neurons, thereby altering the disease course and preventing its progression. Prion diseases are a fascinating group of neurodegenerative diseases because they exhibit a wide phenotypic spectrum caused by different sequence perturbations in a single protein. The possible ways that mutations affecting this protein can cause several distinct neurodegenerative diseases are explored in this Review to highlight the complexity underlying selective vulnerability. The premise of this article is that selective vulnerability is determined by the interaction of specific protein conformers and region-specific microenvironments harboring unique combinations of subcellular components such as metals, chaperones and protein translation machinery. Given the abundance of potential contributory factors in the neurodegenerative process, a better understanding of how these factors interact will provide invaluable insight into disease mechanisms to guide therapeutic discovery.
    Full-text · Article · Jan 2014 · Disease Models and Mechanisms
    • "Our understanding of the mechanisms whereby mutations induce the disease still remains limited. Mutations may increase the likelihood of misfolding by the thermodynamic destabilization of PrP C (Apetri et al. 2004 ; Liemann and Glockshuber 1999 ; Swietnicki et al. 1998 ; Vanik and Surewicz 2002 ) . PrP mutants may escape cellular "
    Giuseppe Legname · Gabriele Giachin · Federico Benetti
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    ABSTRACT: Prion diseases are a group of fatal and incurable neurodegenerative ­disorders of mammals. They uniquely manifest as sporadic, genetic, and infectious maladies. The agent responsible for prion diseases is the prion. A prion is defined as a proteinaceous infectious particle, which is solely constituted by an alternately folded form of the prion protein (PrP) (Prusiner 1982). In diseased animals and humans, PrP exists in two forms, the physiological, cellular form of PrP, PrPC, and the pathological prion form denoted as PrPSc. The mechanism whereby nascent PrPSc is generated is currently unknown. Structural studies of either isoform are of great importance for understanding the biology of prion diseases since they may clarify the molecular mechanisms responsible for these pathologies. In this chapter, we present an overview of the studies into PrPC as well as structures of prions.
    No preview · Chapter · Jan 2012
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    • "V180I) was observed in cell culture experiments [6]. Several mutants also showed decreased thermodynamic stability of PrPC or increased stability of the folding intermediate when studied in vitro [5]. Previously we have shown that separation of subdomain B1-H1-B2 from subdomain H2–H3 is necessary for prion protein conversion while both subdomains retain the arrangement of their secondary structure elements [11]. "
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    ABSTRACT: Prion diseases are fatal neurodegenerative diseases, which can be acquired, sporadic or genetic, the latter being linked to mutations in the gene encoding prion protein. We have recently described the importance of subdomain separation in the conversion of prion protein (PrP). The goal of the present study was to investigate the effect of increasing the hydrophobic interactions within the H2-H3 subdomain on PrP conversion. Three hydrophobic mutations were introduced into PrP. The mutation V209I associated with human prion disease did not alter protein stability or in vitro fibrillization propensity of PrP. The designed mutations V175I and T187I on the other hand increased protein thermal stability. V175I mutant fibrillized faster than wild-type PrP. Conversion delay of T187I was slightly longer, but fluorescence intensity of amyloid specific dye thioflavin T was significantly higher. Surprisingly, cells expressing V209I variant exhibited inefficient proteinase K resistant PrP formation upon infection with 22L strain, which is in contrast to cell lines expressing wild-type, V175I and T187I mPrPs. In agreement with increased ThT fluorescence at the plateau T187I expressing cell lines accumulated an increased amount of the proteinase K-resistant prion protein. We showed that T187I induces formation of thin fibrils, which are absent from other samples. We propose that larger solvent accessibility of I187 in comparison to wild-type and other mutants may interfere with lateral annealing of filaments and may be the underlying reason for increased conversion efficiency.
    Full-text · Article · Sep 2011 · PLoS ONE
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