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Liu, Yanshun; Gotte, Giovanni; Libonati, Massimo; Eisenberg, David

doi:10.1038/84941

Cited by 259 publications

(174 citation statements)

References 26 publications

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“…We demonstrated recently that the assembly of full-length Ure2p into protein fibrils under physiologically relevant conditions is not due to the loss of the tertiary structure of its functional domain (15)(16) but to limited conformational rearrangements, such as domain swapping (27)(28)(29)(30). As a consequence, the fibrils are devoid of a cross ␤-core, and the protein retains its glutathione binding capacity in the fibrils.…”

Section: Discussionmentioning

confidence: 99%

Assembly of the Yeast Prion Ure2p into Protein Fibrils

Fay

Inoue

Bousset

et al. 2003

Journal of Biological Chemistry

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The [URE3] phenotype in Saccharomyces cerevisiaepropagates by a prion mechanism, involving the aggregation of the normally soluble and highly helical protein Ure2. Previous data have shown that the protein spontaneously forms in vitro long, straight, insoluble fibrils at neutral pH that are similar to amyloids in that they bind Congo red and show green-yellow birefringence and have an increased resistance to proteolysis. These fibrils are not amyloids as they are devoid of a cross-␤ core. Here we further document the mechanism of assembly of Ure2p into fibrils. The critical concentration for Ure2p assembly is measured, and the minimal size of the nuclei that are the precursors of Ure2p fibrils is determined. Our data indicate that the assembly process is irreversible. As a consequence, the critical concentration is very low. By analyzing the elongation rates of preformed fibrils and combining the results with singlefiber imaging experiments of a variant Ure2p labeled by fluorescent dyes, we reveal the polarity of the fibrils and differences in the elongation rates at their ends. These results bring novel insight in the process of Ure2p assembly into fibrils and the mechanism of propagation of yeast prions.Creutzfeldt-Jacob disease, bovine spongiform encephalopathy, and sheep scrapie are transmissible spongiform encephalopathies. They are believed to be caused by a constitutive protein called prion protein (PrP) in an altered conformation (1). This rare form of the protein is thought to convert the normal form to the infectious conformation in a catalytic manner (for review, see Ref.2). The molecular events at the origin of propagation are not yet elucidated. In the lower eukaryotes Saccharomyces cerevisiae and Podospora anserina prion proteins have been identified taking advantage of traits they confer (3-7). These proteins are harmless for humans and constitute valuable model systems to characterize prion propagation.The [URE3] phenotype in S. cerevisiae is caused by a disorder in a signal transduction cascade that regulates nitrogen catabolism (8). Yeast cells exhibiting the [URE3] phenotype have the ability to take up ureidosuccinate, the structural analogue of allantoate, a poor nitrogen source in the presence of a good nitrogen source such as ammonium ions. This is believed to be because of the loss of the function of the protein determinant of [URE3], Ure2p, whose function is unknown although reported to be involved in yeast heavy metal and strong oxidant detoxification (9). Importantly, Ure2p [URE3] promotes the conversion of the newly synthesized active Ure2p into an inactive form. Thus, the Ure2p [URE3] state is heritable, independent of any nucleic acid (10).Native soluble Ure2p assembles in vitro into fibrils that exhibit the characteristics of amyloids in that they are about 20 nm wide and more than 1 m long, bind thioflavin T and Congo Red, show yellow-green birefringence in polarized light upon Congo Red binding, and exhibit an increased resistance to proteolysis (11-13). The assembly reaction fo...

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Section: Discussionmentioning

confidence: 99%

Assembly of the Yeast Prion Ure2p into Protein Fibrils

Fay

Inoue

Bousset

et al. 2003

Journal of Biological Chemistry

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“…Different Proteins Can Form Hetero-aggregates-Some cohesive aggregates have been suggested to derive from specific domain-swapping interactions (24,25), implying that aggregation can take place only among identical or very similar polypeptides. Dissimilar co-aggregating polypeptides should therefore not interact with each other or inhibit, rather than accelerate, each other's aggregations (26).…”

Section: Discussionmentioning

confidence: 99%

Proteinaceous Infectious Behavior in Non-pathogenic Proteins Is Controlled by Molecular Chaperones

Ben‐Zvi¹,

Goloubinoff²

2002

Journal of Biological Chemistry

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External stresses or mutations may cause labile proteins to lose their distinct native conformations and seek alternatively stable aggregated forms. Molecular chaperones that specifically act on protein aggregates were used here as a tool to address the biochemical nature of stable homo-and hetero-aggregates from nonpathogenic proteins formed by heat-stress. Confirmed by sedimentation and activity measurements, chaperones demonstrated that a single polypeptide chain can form different species of aggregates, depending on the denaturing conditions. Indicative of a cascade reaction, sub-stoichiometric amounts of one fast-aggregating protein strongly accelerated the conversion of another soluble, slow-aggregating protein into insoluble, chaperone-resistant aggregates. Chaperones strongly inhibited seed-induced protein aggregation, suggesting that they can prevent and cure proteinaceous infectious behavior in homo-and hetero-aggregates from common and disease-associated proteins in the cell.

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“…First, the part of the folding nucleus that is close in sequence could be flickeringly present in the denatured ensemble, providing a potential seed for domain-swap reactions (32), i.e., the protein becomes prone to integrate a matching element from a neighboring molecule. Such domain-swap reactions have been implicated as a key event in fibrillation of globular proteins (33,34) and have been extensively studied for the serpin family where the exchange of individual ␤-strands also has a regulatory function (35). Second, the considerable sequence distance between ␤7 and the other nucleating strands provides an explanation for why the folding of the SOD monomer is slower than for most other Ig domains (cf.…”

Section: The Aposod Monomer Folds Cooperatively According To a Two-statementioning

confidence: 99%

Folding of Cu/Zn superoxide dismutase suggests structural hotspots for gain of neurotoxic function in ALS: Parallels to precursors in amyloid disease

Nordlund

Oliveberg

2006

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

131

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Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease linked to misfolding of the ubiquitous enzyme Cu͞Zn superoxide dismutase (SOD). In contrast to other protein-misfolding disorders with similar neuropathogenesis, ALS is not always associated with the in vivo deposition of protein aggregates. Thus, under the assumption that all protein-misfolding disorders share at primary level a similar disease mechanism, ALS constitutes an interesting disease model for identifying the yet-mysterious precursor states from which the cytotoxic pathway emerges. In this study, we have mapped out the conformational repertoire of the apoSOD monomer through analysis of its folding behavior. The results allow us to target the regions of the SOD structure that are most susceptible to unfolding locally under physiological conditions, leading to the exposure of structurally promiscuous interfaces that are normally hidden in the protein's interior. The structure of this putative ALS precursor is strikingly similar to those implicated in amyloid disease.neurodegenerative disease ͉ protein folding ͉ transition state A n increasing number of severe neurodegenerative disorders have been linked to misfolding and subsequent aggregation of proteins (1). In some cases the protein aggregates deposit in the form of highly ordered amyloid fibrils (2), whereas in other cases they appear more granular or even amorphous (3). Even so, the main cause of neurotoxic function seems not to be the macroscopically deposited protein itself but rather a mysterious precursor species in the aggregation pathway (1, 4-6). In this perspective, it is notable that there are also disease cases where in vivo depositions of the disease-associated proteins are hard to find and sometimes are not even observable. Characteristic examples are found among the sporadic cases of CreuzfeldtJacob disease and amyotropic lateral sclerosis (ALS) (7). It is further apparent that the ALS-associated enzyme Cu͞Zn superoxide dismutase (SOD) has relatively low propensities to aggregate in vitro: SOD can be produced and analyzed by standard protocols despite being destabilized to the extent that it is half unfolded in physiological buffer at 25°C (8). For comparison there are few nondisease proteins that would resist aggregation under these conditions. The question then arises, do the disease cases with and without in vivo deposition of protein aggregates share at the primary level the same toxicity mechanism? We have previously observed that ALS-provoking SOD mutations produce a common shift of the folding equilibrium toward unfolded and partly folded monomers, implicating that the noxious side reaction emerges from the early folding events. The observation is in full agreement with a series of reports pointing at the immature apoSOD monomer as precursor for cytotoxicity (8)(9)(10)(11)(12)(13)(14)(15). Accompanying the shift of the folding equilibrium, the ALS-associated SOD mutations indicate a quantitative relation between decreased protein stability, net charge, and diseas...

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Untitled

Cited by 259 publications

References 26 publications

Assembly of the Yeast Prion Ure2p into Protein Fibrils

Assembly of the Yeast Prion Ure2p into Protein Fibrils

Proteinaceous Infectious Behavior in Non-pathogenic Proteins Is Controlled by Molecular Chaperones

Folding of Cu/Zn superoxide dismutase suggests structural hotspots for gain of neurotoxic function in ALS: Parallels to precursors in amyloid disease

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