1
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Park S, Wang X, Xi W, Richardson R, Laue TM, Denis CL. The non-prion SUP35 preexists in large chaperone-containing molecular complexes. Proteins 2022; 90:869-880. [PMID: 34791707 PMCID: PMC8816864 DOI: 10.1002/prot.26282] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 11/07/2021] [Accepted: 11/09/2021] [Indexed: 12/26/2022]
Abstract
Prions, misfolded proteins that aggregate, cause an array of progressively deteriorating conditions to which, currently, there are no effective treatments. The presently accepted model indicates that the soluble non-prion forms of prion-forming proteins, such as the well-studied SUP35, do not exist in large aggregated molecular complexes. Here, we show using analytical ultracentrifugation with fluorescent detection that the non-prion form of SUP35 exists in a range of discretely sized soluble complexes (19S, 28S, 39S, 57S, and 70S-200S). Similar to the [PSI+] aggregated complexes, each of these [psi-] complexes associates at stoichiometric levels with a large variety of molecular chaperones: HSP70 proteins comprise the major component. Another yeast prion-forming protein, RNQ1 (known to promote the production of the prion SUP35 state), is also present in SUP35 complexes. These results establish that the non-prion SUP35, like its prion form, is predisposed to form large molecular complexes containing chaperones and other prion-forming proteins. These results agree with our previous studies on the huntingtin protein. That the normal forms for aggregation-prone proteins may preexist in large molecular complexes has important ramifications for the progression of diseases involving protein aggregation.
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2
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Serio TR. [PIN+]ing down the mechanism of prion appearance. FEMS Yeast Res 2019; 18:4923032. [PMID: 29718197 PMCID: PMC5889010 DOI: 10.1093/femsyr/foy026] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 03/03/2018] [Indexed: 11/13/2022] Open
Abstract
Prions are conformationally flexible proteins capable of adopting a native state and a spectrum of alternative states associated with a change in the function of the protein. These alternative states are prone to assemble into amyloid aggregates, which provide a structure for self-replication and transmission of the underlying conformer and thereby the emergence of a new phenotype. Amyloid appearance is a rare event in vivo, regulated by both the aggregation propensity of prion proteins and their cellular environment. How these forces normally intersect to suppress amyloid appearance and the ways in which these restrictions can be bypassed to create protein-only phenotypes remain poorly understood. The most widely studied and perhaps most experimentally tractable system to explore the mechanisms regulating amyloid appearance is the [PIN+] prion of Saccharomyces cerevisiae. [PIN+] is required for the appearance of the amyloid state for both native yeast proteins and for human proteins expressed in yeast. These observations suggest that [PIN+] facilitates the bypass of amyloid regulatory mechanisms by other proteins in vivo. Several models of prion appearance are compatible with current observations, highlighting the complexity of the process and the questions that must be resolved to gain greater insight into the mechanisms regulating these events.
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Affiliation(s)
- Tricia R Serio
- The University of Massachusetts-Amherst, Department of Biochemistry and Molecular Biology, 240 Thatcher Rd, N360, Amherst, MA 01003, USA
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3
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Chandramowlishwaran P, Sun M, Casey KL, Romanyuk AV, Grizel AV, Sopova JV, Rubel AA, Nussbaum-Krammer C, Vorberg IM, Chernoff YO. Mammalian amyloidogenic proteins promote prion nucleation in yeast. J Biol Chem 2018; 293:3436-3450. [PMID: 29330303 DOI: 10.1074/jbc.m117.809004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 12/26/2017] [Indexed: 12/26/2022] Open
Abstract
Fibrous cross-β aggregates (amyloids) and their transmissible forms (prions) cause diseases in mammals (including humans) and control heritable traits in yeast. Initial nucleation of a yeast prion by transiently overproduced prion-forming protein or its (typically, QN-rich) prion domain is efficient only in the presence of another aggregated (in most cases, QN-rich) protein. Here, we demonstrate that a fusion of the prion domain of yeast protein Sup35 to some non-QN-rich mammalian proteins, associated with amyloid diseases, promotes nucleation of Sup35 prions in the absence of pre-existing aggregates. In contrast, both a fusion of the Sup35 prion domain to a multimeric non-amyloidogenic protein and the expression of a mammalian amyloidogenic protein that is not fused to the Sup35 prion domain failed to promote prion nucleation, further indicating that physical linkage of a mammalian amyloidogenic protein to the prion domain of a yeast protein is required for the nucleation of a yeast prion. Biochemical and cytological approaches confirmed the nucleation of protein aggregates in the yeast cell. Sequence alterations antagonizing or enhancing amyloidogenicity of human amyloid-β (associated with Alzheimer's disease) and mouse prion protein (associated with prion diseases), respectively, antagonized or enhanced nucleation of a yeast prion by these proteins. The yeast-based prion nucleation assay, developed in our work, can be employed for mutational dissection of amyloidogenic proteins. We anticipate that it will aid in the identification of chemicals that influence initial amyloid nucleation and in searching for new amyloidogenic proteins in a variety of proteomes.
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Affiliation(s)
| | - Meng Sun
- From the School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Kristin L Casey
- From the School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Andrey V Romanyuk
- From the School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Anastasiya V Grizel
- the Laboratory of Amyloid Biology.,Institute of Translational Biomedicine, and
| | - Julia V Sopova
- the Laboratory of Amyloid Biology.,Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia.,the St. Petersburg Branch, N. I. Vavilov Institute of General Genetics, Russian Academy of Sciences, 199034 St. Petersburg, Russia
| | - Aleksandr A Rubel
- the Laboratory of Amyloid Biology.,Institute of Translational Biomedicine, and.,Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Carmen Nussbaum-Krammer
- the Zentrum für Molekulare Biologie der Universität Heidelberg, 69120 Heidelberg, Germany, and
| | - Ina M Vorberg
- the Deutsches Zentrum für Neurodegenerative Erkrankungen, 53175 Bonn, Germany
| | - Yury O Chernoff
- From the School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, .,the Laboratory of Amyloid Biology.,Institute of Translational Biomedicine, and
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4
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Newby GA, Kiriakov S, Hallacli E, Kayatekin C, Tsvetkov P, Mancuso CP, Bonner JM, Hesse WR, Chakrabortee S, Manogaran AL, Liebman SW, Lindquist S, Khalil AS. A Genetic Tool to Track Protein Aggregates and Control Prion Inheritance. Cell 2017; 171:966-979.e18. [PMID: 29056345 DOI: 10.1016/j.cell.2017.09.041] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 07/20/2017] [Accepted: 09/25/2017] [Indexed: 01/05/2023]
Abstract
Protein aggregation is a hallmark of many diseases but also underlies a wide range of positive cellular functions. This phenomenon has been difficult to study because of a lack of quantitative and high-throughput cellular tools. Here, we develop a synthetic genetic tool to sense and control protein aggregation. We apply the technology to yeast prions, developing sensors to track their aggregation states and employing prion fusions to encode synthetic memories in yeast cells. Utilizing high-throughput screens, we identify prion-curing mutants and engineer "anti-prion drives" that reverse the non-Mendelian inheritance pattern of prions and eliminate them from yeast populations. We extend our technology to yeast RNA-binding proteins (RBPs) by tracking their propensity to aggregate, searching for co-occurring aggregates, and uncovering a group of coalescing RBPs through screens enabled by our platform. Our work establishes a quantitative, high-throughput, and generalizable technology to study and control diverse protein aggregation processes in cells.
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Affiliation(s)
- Gregory A Newby
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Szilvia Kiriakov
- Program in Molecular Biology, Cell Biology, and Biochemistry, Boston University, Boston, MA 02215, USA; Biological Design Center, Boston University, Boston, MA 02215, USA
| | - Erinc Hallacli
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Ann Romney Center for Neurologic Disease, Department of Neurology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Can Kayatekin
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Peter Tsvetkov
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Christopher P Mancuso
- Biological Design Center, Boston University, Boston, MA 02215, USA; Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - J Maeve Bonner
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - William R Hesse
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Anita L Manogaran
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53201, USA
| | - Susan W Liebman
- Department of Pharmacology, University of Nevada, Reno, NV 89557, USA
| | - Susan Lindquist
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Cambridge, MA 02139, USA
| | - Ahmad S Khalil
- Biological Design Center, Boston University, Boston, MA 02215, USA; Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA.
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5
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Chan PHW, Lee L, Kim E, Hui T, Stoynov N, Nassar R, Moksa M, Cameron DM, Hirst M, Gsponer J, Mayor T. The [PSI +] yeast prion does not wildly affect proteome composition whereas selective pressure exerted on [PSI +] cells can promote aneuploidy. Sci Rep 2017; 7:8442. [PMID: 28814753 PMCID: PMC5559586 DOI: 10.1038/s41598-017-07999-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 07/07/2017] [Indexed: 11/09/2022] Open
Abstract
The yeast Sup35 protein is a subunit of the translation termination factor, and its conversion to the [PSI +] prion state leads to more translational read-through. Although extensive studies have been done on [PSI +], changes at the proteomic level have not been performed exhaustively. We therefore used a SILAC-based quantitative mass spectrometry approach and identified 4187 proteins from both [psi -] and [PSI +] strains. Surprisingly, there was very little difference between the two proteomes under standard growth conditions. We found however that several [PSI +] strains harbored an additional chromosome, such as chromosome I. Albeit, we found no evidence to support that [PSI +] induces chromosomal instability (CIN). Instead we hypothesized that the selective pressure applied during the establishment of [PSI +]-containing strains could lead to a supernumerary chromosome due to the presence of the ade1-14 selective marker for translational read-through. We therefore verified that there was no prevalence of disomy among newly generated [PSI +] strains in absence of strong selection pressure. We also noticed that low amounts of adenine in media could lead to higher levels of mitochondrial DNA in [PSI +] in ade1-14 cells. Our study has important significance for the establishment and manipulation of yeast strains with the Sup35 prion.
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Affiliation(s)
- Patrick H W Chan
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.,Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Lisa Lee
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.,Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Erin Kim
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.,Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Tony Hui
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Nikolay Stoynov
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Roy Nassar
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Michelle Moksa
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Dale M Cameron
- Department of Biology, Ursinus College, Pennsylvania, USA
| | - Martin Hirst
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Joerg Gsponer
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.,Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Thibault Mayor
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada. .,Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.
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6
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Keefer KM, Stein KC, True HL. Heterologous prion-forming proteins interact to cross-seed aggregation in Saccharomyces cerevisiae. Sci Rep 2017; 7:5853. [PMID: 28724957 PMCID: PMC5517628 DOI: 10.1038/s41598-017-05829-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 06/05/2017] [Indexed: 01/11/2023] Open
Abstract
The early stages of protein misfolding remain incompletely understood, as most mammalian proteinopathies are only detected after irreversible protein aggregates have formed. Cross-seeding, where one aggregated protein templates the misfolding of a heterologous protein, is one mechanism proposed to stimulate protein aggregation and facilitate disease pathogenesis. Here, we demonstrate the existence of cross-seeding as a crucial step in the formation of the yeast prion [PSI +], formed by the translation termination factor Sup35. We provide evidence for the genetic and physical interaction of the prion protein Rnq1 with Sup35 as a predominant mechanism leading to self-propagating Sup35 aggregation. We identify interacting sites within Rnq1 and Sup35 and determine the effects of breaking and restoring a crucial interaction. Altogether, our results demonstrate that single-residue disruption can drastically reduce the effects of cross-seeding, a finding that has important implications for human protein misfolding disorders.
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Affiliation(s)
- Kathryn M Keefer
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, 63110, United States of America
| | - Kevin C Stein
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Heather L True
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, 63110, United States of America.
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7
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Arslan F, Hong JY, Kanneganti V, Park SK, Liebman SW. Heterologous aggregates promote de novo prion appearance via more than one mechanism. PLoS Genet 2015; 11:e1004814. [PMID: 25568955 PMCID: PMC4287349 DOI: 10.1371/journal.pgen.1004814] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 10/09/2014] [Indexed: 12/12/2022] Open
Abstract
Prions are self-perpetuating conformational variants of particular proteins. In yeast, prions cause heritable phenotypic traits. Most known yeast prions contain a glutamine (Q)/asparagine (N)-rich region in their prion domains. [PSI+], the prion form of Sup35, appears de novo at dramatically enhanced rates following transient overproduction of Sup35 in the presence of [PIN+], the prion form of Rnq1. Here, we establish the temporal de novo appearance of Sup35 aggregates during such overexpression in relation to other cellular proteins. Fluorescently-labeled Sup35 initially forms one or a few dots when overexpressed in [PIN+] cells. One of the dots is perivacuolar, colocalizes with the aggregated Rnq1 dot and grows into peripheral rings/lines, some of which also colocalize with Rnq1. Sup35 dots that are not near the vacuole do not always colocalize with Rnq1 and disappear by the time rings start to grow. Bimolecular fluorescence complementation failed to detect any interaction between Sup35-VN and Rnq1-VC in [PSI+][PIN+] cells. In contrast, all Sup35 aggregates, whether newly induced or in established [PSI+], completely colocalize with the molecular chaperones Hsp104, Sis1, Ssa1 and eukaryotic release factor Sup45. In the absence of [PIN+], overexpressed aggregating proteins such as the Q/N-rich Pin4C or the non-Q/N-rich Mod5 can also promote the de novo appearance of [PSI+]. Similar to Rnq1, overexpressed Pin4C transiently colocalizes with newly appearing Sup35 aggregates. However, no interaction was detected between Mod5 and Sup35 during [PSI+] induction in the absence of [PIN+]. While the colocalization of Sup35 and aggregates of Rnq1 or Pin4C are consistent with the model that the heterologous aggregates cross-seed the de novo appearance of [PSI+], the lack of interaction between Mod5 and Sup35 leaves open the possibility of other mechanisms. We also show that Hsp104 is required in the de novo appearance of [PSI+] aggregates in a [PIN+]-independent pathway. Certain proteins can misfold into β-sheet-rich, self-seeding aggregates. Such proteins appear to be associated with neurodegenerative diseases such as prion, Alzheimer's and Parkinson's. Yeast prions also misfold into self-seeding aggregates and provide a good model to study how these rogue polymers first appear. De novo prion appearance can be made very frequent in yeast by transient overexpression of the prion protein in the presence of heterologous prions or prion-like aggregates. Here, we show that the aggregates of one such newly induced prion are initially formed in a dot-like structure near the vacuole. These dots then grow into rings at the periphery of the cell prior to becoming smaller rings surrounding the vacuole and maturing into the characteristic heritable prion tiny dots found throughout the cytoplasm. We found considerable colocalization of two heterologous prion/prion-like aggregates with the newly appearing prion protein aggregates, which is consistent with the prevalent model that existing prion aggregates can cross-seed the de novo aggregation of a heterologous prion protein. However, we failed to find any physical interaction between another heterologous aggregating protein and the newly appearing prion aggregates it stimulated to appear, which is inconsistent with cross-seeding.
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Affiliation(s)
- Fatih Arslan
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
| | - Joo Y. Hong
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
| | - Vydehi Kanneganti
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
| | - Sei-Kyoung Park
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
| | - Susan W. Liebman
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
- * E-mail:
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8
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Sharma J, Liebman SW. Variant-specific prion interactions: Complicating factors. CELLULAR LOGISTICS 2013; 3:e25698. [PMID: 24475372 PMCID: PMC3891757 DOI: 10.4161/cl.25698] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 07/09/2013] [Indexed: 01/09/2023]
Abstract
Prions are protein conformations that “self-seed” the misfolding of their non-prion iso-forms into prion, often amyloid, conformations. The most famous prion is the mammalian PrP protein that in its prion form causes transmissible spongiform encephalopathy. Curiously there can be distinct conformational differences even between prions of the same protein propagated in the same host species. These are called prion strains or variants. For example, different PrP variants are faithfully transmitted during self-seeding and are associated with distinct disease characteristics. Variant-specific PrP prion differences include the length of the incubation period before the disease appears and the deposition of prion aggregates in distinct regions of the brain.1 Other more common neurodegenerative diseases (e.g., Alzheimer disease, Parkinson disease, type 2 diabetes and ALS) are likewise caused by the misfolding of a normal protein into a self-seeding aggregate.2-4 One of the most important unanswered questions is how the first prion-like seed arises de novo, resulting in the pathological cascade.
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Affiliation(s)
- Jaya Sharma
- Department of Biological Sciences; University of Illinois at Chicago; Chicago, IL USA
| | - Susan W Liebman
- Department of Biological Sciences; University of Illinois at Chicago; Chicago, IL USA ; Department of Biochemistry and Molecular Biology; University of Nevada Reno; Reno, NV USA
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9
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Exploring the basis of [PIN(+)] variant differences in [PSI(+)] induction. J Mol Biol 2013; 425:3046-59. [PMID: 23770111 DOI: 10.1016/j.jmb.2013.06.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 05/07/2013] [Accepted: 06/07/2013] [Indexed: 01/12/2023]
Abstract
Certain soluble proteins can form amyloid-like prion aggregates. Indeed, the same protein can make different types of aggregates, called variants. Each variant is heritable because it attracts soluble homologous protein to join its aggregate, which is then broken into seeds (propagons) and transmitted to daughter cells. [PSI(+)] and [PIN(+)] are respectively prion forms of Sup35 and Rnq1. Curiously, [PIN(+)] enhances the de novo induction of [PSI(+)]. Different [PIN(+)] variants do this to dramatically different extents. Here, we investigate the mechanism underlying this effect. Consistent with a heterologous prion cross-seeding model, different [PIN(+)] variants preferentially promoted the appearance of different variants of [PSI(+)]. However, we did not detect this specificity in vitro. Also, [PIN(+)] variant cross-seeding efficiencies were not proportional to the level of Rnq1 coimmunocaptured with Sup35 or to the number of [PIN(+)] propagons characteristic for that variant. This leads us to propose that [PIN(+)] variants differ in the cross-seeding quality of their seeds, following the Sup35/[PIN(+)] binding step.
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10
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Yang Z, Hong JY, Derkatch IL, Liebman SW. Heterologous gln/asn-rich proteins impede the propagation of yeast prions by altering chaperone availability. PLoS Genet 2013; 9:e1003236. [PMID: 23358669 PMCID: PMC3554615 DOI: 10.1371/journal.pgen.1003236] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 11/26/2012] [Indexed: 12/16/2022] Open
Abstract
Prions are self-propagating conformations of proteins that can cause heritable phenotypic traits. Most yeast prions contain glutamine (Q)/asparagine (N)-rich domains that facilitate the accumulation of the protein into amyloid-like aggregates. Efficient transmission of these infectious aggregates to daughter cells requires that chaperones, including Hsp104 and Sis1, continually sever the aggregates into smaller “seeds.” We previously identified 11 proteins with Q/N-rich domains that, when overproduced, facilitate the de novo aggregation of the Sup35 protein into the [PSI+] prion state. Here, we show that overexpression of many of the same 11 Q/N-rich proteins can also destabilize pre-existing [PSI+] or [URE3] prions. We explore in detail the events leading to the loss (curing) of [PSI+] by the overexpression of one of these proteins, the Q/N-rich domain of Pin4, which causes Sup35 aggregates to increase in size and decrease in transmissibility to daughter cells. We show that the Pin4 Q/N-rich domain sequesters Hsp104 and Sis1 chaperones away from the diffuse cytoplasmic pool. Thus, a mechanism by which heterologous Q/N-rich proteins impair prion propagation appears to be the loss of cytoplasmic Hsp104 and Sis1 available to sever [PSI+]. Certain proteins can occasionally misfold into infectious aggregates called prions. Once formed, these aggregates grow by attracting the soluble form of that protein to join them. The presence of these aggregates can cause profound effects on cells and, in humans, can cause diseases such as transmissible spongiform encephalopathies (TSEs). In yeast, the aggregates are efficiently transmitted to daughter cells because they are cut into small pieces by molecular scissors (chaperones). Here we show that heritable prion aggregates are frequently lost when we overproduce certain other proteins with curing activity. We analyzed one such protein in detail and found that when it is overproduced it forms aggregates that sequester chaperones. This sequestration appears to block the ability of the chaperones to cut the prion aggregates. The result is that the prions get too large to be transmitted to daughter cells. Such sequestration of molecular scissors provides a potential approach to thwart the propagation of disease-causing infectious protein aggregates.
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Affiliation(s)
- Zi Yang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Joo Y. Hong
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
| | - Irina L. Derkatch
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Neuroscience, Columbia University, New York, New York, United States of America
| | - Susan W. Liebman
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
- * E-mail:
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11
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Sharma J, Liebman SW. [PSI(+) ] prion variant establishment in yeast. Mol Microbiol 2012; 86:866-81. [PMID: 22998111 DOI: 10.1111/mmi.12024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2012] [Indexed: 10/27/2022]
Abstract
Differences in the clinical pathology of mammalian prion diseases reflect distinct heritable conformations of aggregated PrP proteins, called prion strains. Here, using the yeast [PSI(+) ] prion, we examine the de novo establishment of prion strains (called variants in yeast). The [PSI(+) ] prion protein, Sup35, is efficiently induced to take on numerous prion variant conformations following transient overexpression of Sup35 in the presence of another prion, e.g. [PIN(+) ]. One hypothesis is that the first [PSI(+) ] prion seed to arise in a cell causes propagation of only that seed's variant, but that different variants could be initiated in different cells. However, we now show that even within a single cell, Sup35 retains the potential to fold into more than one variant type. When individual cells segregating different [PSI(+) ] variants were followed in pedigrees, establishment of a single variant phenotype generally occurred in daughters, granddaughters or great-granddaughters - but in 5% of the pedigrees cells continued to segregate multiple variants indefinitely. The data are consistent with the idea that many newly formed prions go through a maturation phase before they reach a single specific variant conformation. These findings may be relevant to mammalian PrP prion strain establishment and adaptation.
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Affiliation(s)
- Jaya Sharma
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
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12
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Abstract
The concept of a prion as an infectious self-propagating protein isoform was initially proposed to explain certain mammalian diseases. It is now clear that yeast also has heritable elements transmitted via protein. Indeed, the "protein only" model of prion transmission was first proven using a yeast prion. Typically, known prions are ordered cross-β aggregates (amyloids). Recently, there has been an explosion in the number of recognized prions in yeast. Yeast continues to lead the way in understanding cellular control of prion propagation, prion structure, mechanisms of de novo prion formation, specificity of prion transmission, and the biological roles of prions. This review summarizes what has been learned from yeast prions.
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Affiliation(s)
- Susan W Liebman
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA.
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13
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Gonzalez Nelson AC, Ross ED. Interactions between non-identical prion proteins. Semin Cell Dev Biol 2011; 22:437-43. [PMID: 21354317 DOI: 10.1016/j.semcdb.2011.02.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Revised: 02/16/2011] [Accepted: 02/17/2011] [Indexed: 11/24/2022]
Abstract
Prion formation involves the conversion of soluble proteins into an infectious amyloid form. This process is highly specific, with prion aggregates templating the conversion of identical proteins. However, in some cases non-identical prion proteins can interact to promote or inhibit prion formation or propagation. These interactions affect both the efficiency with which prion diseases are transmitted across species and the normal physiology of yeast prion formation and propagation. Here we examine two types of heterologous prion interactions: interactions between related proteins from different species (the species barrier) and interactions between unrelated prion proteins within a single species. Interestingly, although very subtle changes in protein sequence can significantly reduce or eliminate cross-species prion transmission, in Saccharomyces cerevisiae completely unrelated prion proteins can interact to affect prion formation and propagation.
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Affiliation(s)
- Aaron C Gonzalez Nelson
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
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Current awareness on yeast. Yeast 2010. [DOI: 10.1002/yea.1713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Ross CD, McCarty BR, Hamilton M, Ben-Hur A, Ross ED. A promiscuous prion: efficient induction of [URE3] prion formation by heterologous prion domains. Genetics 2009; 183:929-40. [PMID: 19752212 PMCID: PMC2778988 DOI: 10.1534/genetics.109.109322] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Accepted: 09/05/2009] [Indexed: 11/18/2022] Open
Abstract
The [URE3] and [PSI(+)] prions are the infections amyloid forms of the Saccharomyces cerevisiae proteins Ure2p and Sup35p, respectively. Randomizing the order of the amino acids in the Ure2 and Sup35 prion domains while retaining amino acid composition does not block prion formation, indicating that amino acid composition, not primary sequence, is the predominant feature driving [URE3] and [PSI(+)] formation. Here we show that Ure2p promiscuously interacts with various compositionally similar proteins to influence [URE3] levels. Overexpression of scrambled Ure2p prion domains efficiently increases de novo formation of wild-type [URE3] in vivo. In vitro, amyloid aggregates of the scrambled prion domains efficiently seed wild-type Ure2p amyloid formation, suggesting that the wild-type and scrambled prion domains can directly interact to seed prion formation. To test whether interactions between Ure2p and naturally occurring yeast proteins could similarly affect [URE3] formation, we identified yeast proteins with domains that are compositionally similar to the Ure2p prion domain. Remarkably, all but one of these domains were also able to efficiently increase [URE3] formation. These results suggest that a wide variety of proteins could potentially affect [URE3] formation.
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Affiliation(s)
- Carley D. Ross
- Department of Biochemistry and Molecular Biology and Department of Computer Science, Colorado State University, Fort Collins, Colorado 80523
| | - Blake R. McCarty
- Department of Biochemistry and Molecular Biology and Department of Computer Science, Colorado State University, Fort Collins, Colorado 80523
| | - Michael Hamilton
- Department of Biochemistry and Molecular Biology and Department of Computer Science, Colorado State University, Fort Collins, Colorado 80523
| | - Asa Ben-Hur
- Department of Biochemistry and Molecular Biology and Department of Computer Science, Colorado State University, Fort Collins, Colorado 80523
| | - Eric D. Ross
- Department of Biochemistry and Molecular Biology and Department of Computer Science, Colorado State University, Fort Collins, Colorado 80523
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