Effect of transition metals (Mn, Cu, Fe) and deoxycholic acid (DA) on the conversion of PrP<sup>C</sup>to PrP<sup>res</sup>

Kim, Nam-Ho; Choi, Joo Hee; Jeong, Byung‐Hoon; Kim, Jae-Il; Kwon, Myung-Sang; Carp, Richard I.; Kim, Yong‐Sun

doi:10.1096/fj.04-2117fje

Cited by 65 publications

(57 citation statements)

References 42 publications

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“…The binding of manganese to PrP potentially results in the conversion of the protein to an abnormal isoform with properties reminiscent of PrP Sc (8,26). In particular, manganese-bound PrP shows greater protease resistance (27), increased ␤-sheet content, the ability to aggregate (28), and the ability to seed polymerization of further prion protein (26). These effects are observed in recombinant protein and protein expressed in cells (29).…”

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confidence: 99%

Manganese Binding to the Prion Protein

Brazier

Davies

Player

et al. 2008

Journal of Biological Chemistry

102

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There is considerable evidence that the prion protein binds copper. However, there have also been suggestions that prion protein (PrP) binds manganese. We used isothermal titration calorimetry to identify the manganese binding sites in wild-type mouse PrP. The protein showed two manganese binding sites with affinities that would bind manganese at concentrations of 63 and 200 M at pH 5.5. This indicates that PrP binds manganese with affinity similar to other known manganese-binding proteins. Further study indicated that the main manganese binding site is associated with His-95 in the so-called "fifth site" normally associated with copper binding. Additionally, it was shown that occupancy by copper does not prevent manganese binding. Under these conditions, manganese binding resulted in an altered conformation of PrP, displacement of copper, and altered redox chemistry of the metal-protein complex. Cyclic voltammetric measurements suggested a complex redox chemistry involving manganese bound to PrP, whereas copper-bound PrP was able to undergo fully reversible electron cycling. Additionally, manganese binding to PrP converted it to a form able to catalyze aggregation of metal-free PrP. These results further support the notion that manganese binding could cause a conformation change in PrP and trigger changes in the protein similar to those associated with prion disease.

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confidence: 99%

Manganese Binding to the Prion Protein

Brazier

Davies

Player

et al. 2008

Journal of Biological Chemistry

102

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“…This structure acts as a "seed" recruiting additional PrP M , eventually leading to the formation of PrP Sc . Accumulated evidence suggests that the conversion process may require the participation of other macromolecules, such as glycosaminoglycans (6 -8), nucleic acids (9,10), lipids (11,12), cellular proteins, such as chaperone proteins (13,14), or divalent cations (15,16). The mechanism by which a PrP M causes neuropathology remains unclear.…”

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Binding of Recombinant but Not Endogenous Prion Protein to DNA Causes DNA Internalization and Expression in Mammalian Cells

Yin

Fan

et al. 2008

Journal of Biological Chemistry

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Recombinant prion protein, rPrP, binds DNA. Both the KKRPK motif and the octapeptide repeat region of rPrP are essential for maximal binding. rPrP with pathogenic insertional mutations binds more DNA than wild-type rPrP. DNA promotes the aggregation of rPrP and protects its N terminus from proteinase K digestion. When rPrP is mixed with an expression plasmid and Ca 2؉ , the rPrP⅐DNA complex is taken up by mammalian cells leading to gene expression. In the presence of Ca 2؉ , rPrP by itself is also taken up by cells in a temperature-and pinocytosis-dependent manner. Cells do not take up rPrP ⌬KKRPK , which lacks the KKRPK motif. Thus, rPrP is the carrier for DNA and the KKRPK motif is essential for its uptake. When mixed with DNA, a pentapeptide KKRPK, but not KKKKK, is sufficient for DNA internalization and expression. In contrast, whereas the normal cellular prion protein, PrP C , on the cell surface can also internalize DNA, the imported DNA is not expressed. These findings may have relevance to the normal functions of PrP C and the pathogenic mechanisms of human prion disease.Human prion diseases constitute a group of fatal neurodegenerative diseases (1, 2). The majority of human prion diseases are sporadic, in which the pathogenic mechanisms are not known. Human prion diseases, such as Kuru and iatrogenic and variant Creutzfeld-Jacob disease, are contracted by an infectious mechanism. On the other hand, inherited human prion disease, which accounts for about 10% of human prion disease, is caused by mutation of the germline prion gene, PRNP.More than 30 different pathogenic mutations in the human PRNP gene have been identified (3). These mutations are either insertional or point mutations. Insertion mutation occurs solely in the octapeptide repeat region; wild-type human (PrP C ) 2 has five octapeptide repeats. Point mutations occur along the entire PrP C molecule. It is thought that the mutant prion protein, PrP M , is inherently unstable, leading to self-association to produce an oligomeric structure (4, 5). This structure acts as a "seed" recruiting additional PrP M , eventually leading to the formation of PrP Sc . Accumulated evidence suggests that the conversion process may require the participation of other macromolecules, such as glycosaminoglycans (6 -8), nucleic acids (9, 10), lipids (11, 12), cellular proteins, such as chaperone proteins (13,14), or divalent cations (15, 16). The mechanism by which a PrP M causes neuropathology remains unclear. PrP M may cause disease because of a gain of toxic function, loss of normal function, or both.Bacteria-produced recombinant prion proteins, rPrPs, have been used extensively as model systems to study the differences between wild-type rPrP and rPrP M (17-19). Biophysical studies suggest that thermoinstability is not the major contributing factor in the conversion process (20,21). Recently, we reported that rPrP M s with pathogenic mutations have a more exposed N terminus and bind more glycosaminoglycan (GAG) (22, 23). Binding of GAG also promotes the aggregati...

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“…The formation of β-sheets containing amyloid fibrils from disease-associated proteins, such as the β-amyloid protein (AβP), the prion protein, α-synuclein, and polyglutamine, are implicated in the pathogenesis of Alzheimer's disease, prion diseases, Parkinson's disease (PD) and Huntington disease, respectively. One of the best described examples of protein conformational changes induced by iron is the prion protein (PrP c ) that undergoes a conformational change to PrP-scrapie (PrPsc) (39,40). Furthermore, the loss of normal function of PrP c due to aggregation to the PrP sc form induces iron dyshomeostasis in prion disease affected brains, resulting in disease associated neurotoxicity (34).…”

Section: Discussionmentioning

confidence: 99%

H ferritin silencing induces protein misfolding in K562 cells: A Raman analysis

Zolea

Biamonte

Candeloro

et al. 2015

Free Radical Biology and Medicine

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The redox state of the cell is involved in the regulation of many physiological functions as well as in the pathogenesis of several diseases, and is strictly dependent on the amount of iron in its catalytically active state.Alterations of iron homeostasis determine increased steady-state concentrations of Reactive Oxygen Species (ROS) that cause lipid peroxidation, DNA damage and altered protein folding. Ferritin keeps the intracellular iron in a non-toxic and readily available form and consequently plays a central role in iron and redox homeostasis. The protein is composed by 24 subunits of the H-and L-type, coded by two different genes, with structural and functional differences. The aim of this study was to shed light on the role of the single H ferritin subunit (FHC) in keeping the native correct protein three-dimensional structure. To this, we performed Raman spectroscopy on protein extracts from K562 cells subjected to FHC silencing. The results show a significant increase in the percentage of disordered structures content at a level comparable to that induced by H 2 O 2 treatment in control cells. ROS inhibitor and iron chelator were able to revert protein misfolding. This integrated approach, involving Raman spectroscopy and targeted-gene silencing, indicates that an imbalance of the heavyto-light chain ratio in the ferritin composition is able to induce severe but still reversible modifications in protein folding and uncovers new potential pathogenetic mechanisms associated to intracellular iron perturbation.

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Effect of transition metals (Mn, Cu, Fe) and deoxycholic acid (DA) on the conversion of PrP^Cto PrP^res

Cited by 65 publications

References 42 publications

Manganese Binding to the Prion Protein

Manganese Binding to the Prion Protein

Binding of Recombinant but Not Endogenous Prion Protein to DNA Causes DNA Internalization and Expression in Mammalian Cells

H ferritin silencing induces protein misfolding in K562 cells: A Raman analysis

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Effect of transition metals (Mn, Cu, Fe) and deoxycholic acid (DA) on the conversion of PrPCto PrPres

Cited by 65 publications

References 42 publications

Manganese Binding to the Prion Protein

Manganese Binding to the Prion Protein

Binding of Recombinant but Not Endogenous Prion Protein to DNA Causes DNA Internalization and Expression in Mammalian Cells

H ferritin silencing induces protein misfolding in K562 cells: A Raman analysis

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Effect of transition metals (Mn, Cu, Fe) and deoxycholic acid (DA) on the conversion of PrP^Cto PrP^res