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Sweeny EA, Tariq A, Gurpinar E, Go MS, Sochor MA, Kan ZY, Mayne L, Englander SW, Shorter J. Structural and mechanistic insights into Hsp104 function revealed by synchrotron X-ray footprinting. J Biol Chem 2020; 295:1517-1538. [PMID: 31882541 PMCID: PMC7008382 DOI: 10.1074/jbc.ra119.011577] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/23/2019] [Indexed: 01/11/2023] Open
Abstract
Hsp104 is a hexameric AAA+ ring translocase, which drives protein disaggregation in nonmetazoan eukaryotes. Cryo-EM structures of Hsp104 have suggested potential mechanisms of substrate translocation, but precisely how Hsp104 hexamers disaggregate proteins remains incompletely understood. Here, we employed synchrotron X-ray footprinting to probe the solution-state structures of Hsp104 monomers in the absence of nucleotide and Hsp104 hexamers in the presence of ADP or ATPγS (adenosine 5'-O-(thiotriphosphate)). Comparing side-chain solvent accessibilities between these three states illuminated aspects of Hsp104 structure and guided design of Hsp104 variants to probe the disaggregase mechanism in vitro and in vivo We established that Hsp104 hexamers switch from a more-solvated state in ADP to a less-solvated state in ATPγS, consistent with switching from an open spiral to a closed ring visualized by cryo-EM. We pinpointed critical N-terminal domain (NTD), NTD-nucleotide-binding domain 1 (NBD1) linker, NBD1, and middle domain (MD) residues that enable intrinsic disaggregase activity and Hsp70 collaboration. We uncovered NTD residues in the loop between helices A1 and A2 that can be substituted to enhance disaggregase activity. We elucidated a novel potentiated Hsp104 MD variant, Hsp104-RYD, which suppresses α-synuclein, fused in sarcoma (FUS), and TDP-43 toxicity. We disambiguated a secondary pore-loop in NBD1, which collaborates with the NTD and NBD1 tyrosine-bearing pore-loop to drive protein disaggregation. Finally, we defined Leu-601 in NBD2 as crucial for Hsp104 hexamerization. Collectively, our findings unveil new facets of Hsp104 structure and mechanism. They also connect regions undergoing large changes in solvation to functionality, which could have profound implications for protein engineering.
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Affiliation(s)
- Elizabeth A Sweeny
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
| | - Amber Tariq
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Esin Gurpinar
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Michelle S Go
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Matthew A Sochor
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Zhong-Yuan Kan
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Johnson Research Foundation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Leland Mayne
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Johnson Research Foundation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - S Walter Englander
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Johnson Research Foundation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - James Shorter
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
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2
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Abstract
Protein misfolding and aggregation underpin several fatal neurodegenerative diseases, including Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and frontotemporal dementia (FTD). There are no treatments that directly antagonize the protein-misfolding events that cause these disorders. Agents that reverse protein misfolding and restore proteins to native form and function could simultaneously eliminate any deleterious loss-of-function or toxic gain-of-function caused by misfolded conformers. Moreover, a disruptive technology of this nature would eliminate self-templating conformers that spread pathology and catalyze formation of toxic, soluble oligomers. Here, we highlight our efforts to engineer Hsp104, a protein disaggregase from yeast, to more effectively disaggregate misfolded proteins connected with PD, ALS, and FTD. Remarkably subtle modifications of Hsp104 primary sequence yielded large gains in protective activity against deleterious α-synuclein, TDP-43, FUS, and TAF15 misfolding. Unusually, in many cases loss of amino acid identity at select positions in Hsp104 rather than specific mutation conferred a robust therapeutic gain-of-function. Nevertheless, the misfolding and toxicity of EWSR1, an RNA-binding protein with a prion-like domain linked to ALS and FTD, could not be buffered by potentiated Hsp104 variants, indicating that further amelioration of disaggregase activity or sharpening of substrate specificity is warranted. We suggest that neuroprotection is achievable for diverse neurodegenerative conditions via surprisingly subtle structural modifications of existing chaperones.
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Affiliation(s)
- Meredith E Jackrel
- a Department of Biochemistry and Biophysics ; Perelman School of Medicine at the University of Pennsylvania ; Philadelphia , PA USA
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3
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Torrente MP, Chuang E, Noll MM, Jackrel ME, Go MS, Shorter J. Mechanistic Insights into Hsp104 Potentiation. J Biol Chem 2016; 291:5101-15. [PMID: 26747608 DOI: 10.1074/jbc.m115.707976] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Indexed: 12/25/2022] Open
Abstract
Potentiated variants of Hsp104, a protein disaggregase from yeast, can dissolve protein aggregates connected to neurodegenerative diseases such as Parkinson disease and amyotrophic lateral sclerosis. However, the mechanisms underlying Hsp104 potentiation remain incompletely defined. Here, we establish that 2-3 subunits of the Hsp104 hexamer must bear an A503V potentiating mutation to elicit enhanced disaggregase activity in the absence of Hsp70. We also define the ATPase and substrate-binding modalities needed for potentiated Hsp104(A503V) activity in vitro and in vivo. Hsp104(A503V) disaggregase activity is strongly inhibited by the Y257A mutation that disrupts substrate binding to the nucleotide-binding domain 1 (NBD1) pore loop and is abolished by the Y662A mutation that disrupts substrate binding to the NBD2 pore loop. Intriguingly, Hsp104(A503V) disaggregase activity responds to mixtures of ATP and adenosine 5'-(γ-thio)-triphosphate (a slowly hydrolyzable ATP analogue) differently from Hsp104. Indeed, an altered pattern of ATP hydrolysis and altered allosteric signaling between NBD1 and NBD2 are likely critical for potentiation. Hsp104(A503V) variants bearing inactivating Walker A or Walker B mutations in both NBDs are inoperative. Unexpectedly, however, Hsp104(A503V) retains potentiated activity upon introduction of sensor-1 mutations that reduce ATP hydrolysis at NBD1 (T317A) or NBD2 (N728A). Hsp104(T317A/A503V) and Hsp104(A503V/N728A) rescue TDP-43 (TAR DNA-binding protein 43), FUS (fused in sarcoma), and α-synuclein toxicity in yeast. Thus, Hsp104(A503V) displays a more robust activity that is unperturbed by sensor-1 mutations that greatly reduce Hsp104 activity in vivo. Indeed, ATPase activity at NBD1 or NBD2 is sufficient for Hsp104 potentiation. Our findings will empower design of ameliorated therapeutic disaggregases for various neurodegenerative diseases.
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Affiliation(s)
| | - Edward Chuang
- From the Department of Biochemistry and Biophysics and the Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Megan M Noll
- From the Department of Biochemistry and Biophysics and
| | | | - Michelle S Go
- From the Department of Biochemistry and Biophysics and
| | - James Shorter
- From the Department of Biochemistry and Biophysics and the Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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4
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Jackrel ME, Yee K, Tariq A, Chen AI, Shorter J. Disparate Mutations Confer Therapeutic Gain of Hsp104 Function. ACS Chem Biol 2015; 10:2672-9. [PMID: 26441009 DOI: 10.1021/acschembio.5b00765] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hsp104, a protein disaggregase from yeast, can be engineered and potentiated to counter TDP-43, FUS, or α-synuclein misfolding and toxicity implicated in neurodegenerative disease. Here, we reveal that extraordinarily disparate mutations potentiate Hsp104. Remarkably, diverse single missense mutations at 20 different positions interspersed throughout the middle domain (MD) and small domain of nucleotide-binding domain 1 (NBD1) confer a therapeutic gain of Hsp104 function. Moreover, potentiation emerges from deletion of MD helix 3 or 4 or via synergistic missense mutations in the MD distal loop and helix 4. We define the most critical aspect of Hsp104 potentiation as enhanced disaggregase activity in the absence of Hsp70 and Hsp40. We suggest that potentiation likely stems from a loss of a fragilely constrained autoinhibited state that enables precise spatiotemporal regulation of disaggregase activity.
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Affiliation(s)
- Meredith E. Jackrel
- Department of Biochemistry and Biophysics, ‡Cell and Molecular Biology Graduate
Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Keolamau Yee
- Department of Biochemistry and Biophysics, ‡Cell and Molecular Biology Graduate
Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Amber Tariq
- Department of Biochemistry and Biophysics, ‡Cell and Molecular Biology Graduate
Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Annie I. Chen
- Department of Biochemistry and Biophysics, ‡Cell and Molecular Biology Graduate
Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - James Shorter
- Department of Biochemistry and Biophysics, ‡Cell and Molecular Biology Graduate
Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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5
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Dulle JE, True HL. Low activity of select Hsp104 mutants is sufficient to propagate unstable prion variants. Prion 2013; 7:394-403. [PMID: 24064980 DOI: 10.4161/pri.26547] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The molecular chaperone network plays a critical role in the formation and propagation of self-replicating yeast prions. Not only do individual prions differ in their requirements for certain chaperones, but structural variants of the same prion can also display distinct dependences on the chaperone machinery, specifically Hsp104. The AAA+ ATPase Hsp104 is a disaggregase required for the maintenance of most known yeast prions. As a key component in the propagation of prions, understanding how Hsp104 differs in its interaction with specific variants is crucial to understanding how prion variants may be selected or evolve. Here, we investigate two novel mutations in Hsp104, hsp104-G254D, and hsp104-G730D, which allow us to elucidate some mechanistic features of Hsp104 disaggregation and its requirement for activity in propagating specific prion variants. Both Hsp104 mutants propagate the [PSI+] prion to some extent, but show a high rate of prion loss. Both Hsp104-G254D and Hsp104-G730D display reduced biochemical activity, yet differ in their ability to efficiently resolubilize disordered, heat-aggregated substrates. Additionally, both mutants impair weak [PSI+] propagation, but are capable of propagating the less stable strong [PSI+] variant to some extent. One of the Hsp104 mutants also has the ability to propagate one variant of the [RNQ+] prion. Thus, our data suggest that changes in Hsp104 activity limit substrate disaggregation in a manner that depends more on the stability of the substrate than the nature of the aggregated species.
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Affiliation(s)
- Jennifer E Dulle
- Department of Cell Biology and Physiology; Washington University in St. Louis; St. Louis, MO USA
| | - Heather L True
- Department of Cell Biology and Physiology; Washington University in St. Louis; St. Louis, MO USA
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Wu TY, Juan YT, Hsu YH, Wu SH, Liao HT, Fung RW, Charng YY. Interplay between heat shock proteins HSP101 and HSA32 prolongs heat acclimation memory posttranscriptionally in Arabidopsis. PLANT PHYSIOLOGY 2013; 161:2075-84. [PMID: 23439916 PMCID: PMC3613477 DOI: 10.1104/pp.112.212589] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 02/23/2013] [Indexed: 05/20/2023]
Abstract
Heat acclimation improves the tolerance of organisms to severe heat stress. Our previous work showed that in Arabidopsis (Arabidopsis thaliana), the "memory" of heat acclimation treatment decayed faster in the absence of the heat-stress-associated 32-kD protein HSA32, a heat-induced protein predominantly found in plants. The HSA32 null mutant attains normal short-term acquired thermotolerance but is defective in long-term acquired thermotolerance. To further explore this phenomenon, we isolated Arabidopsis defective in long-term acquired thermotolerance (dlt) mutants using a forward genetic screen. Two recessive missense alleles, dlt1-1 and dlt1-2, encode the molecular chaperone heat shock protein101 (HSP101). Results of immunoblot analyses suggest that HSP101 enhances the translation of HSA32 during recovery after heat treatment, and in turn, HSA32 retards the decay of HSP101. The dlt1-1 mutation has little effect on HSP101 chaperone activity and thermotolerance function but compromises the regulation of HSA32. In contrast, dlt1-2 impairs the chaperone activity and thermotolerance function of HSP101 but not the regulation of HSA32. These results suggest that HSP101 has a dual function, which could be decoupled by the mutations. Pulse-chase analysis showed that HSP101 degraded faster in the absence of HSA32. The autophagic proteolysis inhibitor E-64d, but not the proteasome inhibitor MG132, inhibited the degradation of HSP101. Ectopic expression of HSA32 confirmed its effect on the decay of HSP101 at the posttranscriptional level and showed that HSA32 was not sufficient to confer long-term acquired thermotolerance when the HSP101 level was low. Taken together, we propose that a positive feedback loop between HSP101 and HSA32 at the protein level is a novel mechanism for prolonging the memory of heat acclimation.
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MESH Headings
- Acclimatization/drug effects
- Acclimatization/genetics
- Arabidopsis/drug effects
- Arabidopsis/genetics
- Arabidopsis/physiology
- Arabidopsis Proteins/metabolism
- Autophagy/drug effects
- Autophagy/genetics
- Crosses, Genetic
- Cycloheximide/pharmacology
- Epistasis, Genetic/drug effects
- Ethyl Methanesulfonate
- Gene Expression Regulation, Plant/drug effects
- Genetic Complementation Test
- Heat-Shock Proteins/metabolism
- Hot Temperature
- Leucine/analogs & derivatives
- Leucine/pharmacology
- Luciferases/metabolism
- Mutation, Missense/genetics
- Phenotype
- Plant Proteins/metabolism
- Plants, Genetically Modified
- Protein Stability/drug effects
- Proteolysis/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Stress, Physiological/drug effects
- Stress, Physiological/genetics
- Time Factors
- Transcription Factors/metabolism
- Transcription, Genetic
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7
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Winkler J, Tyedmers J, Bukau B, Mogk A. Chaperone networks in protein disaggregation and prion propagation. J Struct Biol 2012; 179:152-60. [PMID: 22580344 DOI: 10.1016/j.jsb.2012.05.002] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 04/27/2012] [Accepted: 05/01/2012] [Indexed: 11/30/2022]
Abstract
The oligomeric AAA+ chaperones Escherichia coli ClpB and Saccharomyces cerevisiae Hsp104 cooperate with cognate Hsp70/Hsp40 chaperone machineries in the reactivation of aggregated proteins in E. coli and S. cerevisiae. In addition, Hsp104 and Hsp70/Hsp40 are crucial for the maintenance of prion aggregates in yeast cells. While the bichaperone system efficiently solubilizes stress-generated amorphous aggregates, structurally highly ordered prion fibrils are only partially processed, resulting in the generation of fragmented prion seeds that can be transmitted to daughter cells for stable inheritance. Here, we describe and discuss the most recent mechanistic findings on yeast Hsp104 and Hsp70/Hsp40 cooperation in the remodeling of both types of aggregates, emphasizing similarities in the mechanism but also differences in the sensitivities towards chaperone activities.
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Affiliation(s)
- Juliane Winkler
- Center for Molecular Biology of the University of Heidelberg and German Cancer Research Center, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg D-69120, Germany
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8
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Desantis ME, Shorter J. The elusive middle domain of Hsp104 and ClpB: location and function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1823:29-39. [PMID: 21843558 DOI: 10.1016/j.bbamcr.2011.07.014] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 07/13/2011] [Accepted: 07/18/2011] [Indexed: 12/17/2022]
Abstract
Hsp104 in yeast and ClpB in bacteria are homologous, hexameric AAA+ proteins and Hsp100 chaperones, which function in the stress response as ring-translocases that drive protein disaggregation and reactivation. Both Hsp104 and ClpB contain a distinctive coiled-coil middle domain (MD) inserted in the first AAA+ domain, which distinguishes them from other AAA+ proteins and Hsp100 family members. Here, we focus on recent developments concerning the location and function of the MD in these hexameric molecular machines, which remains an outstanding question. While the atomic structure of the hexameric assembly of Hsp104 and ClpB remains uncertain, recent advances have illuminated that the MD is critical for the intrinsic disaggregase activity of the hexamer and mediates key functional interactions with the Hsp70 chaperone system (Hsp70 and Hsp40) that empower protein disaggregation.
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Affiliation(s)
- Morgan E Desantis
- Department of Biochemistry and Biophysics, Perelman School of Medicine at The University of Pennsylvania, 805b Stellar-Chance Laboratories, 422 Curie Boulevard, Philadelphia, PA 19104, USA
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9
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Nevzglyadova OV, Artemov AV, Mittenberg AG, Kostyleva EI, Mikhailova EV, Solovyov KV, Kuznetsova IM, Turoverov KK, Soidla TR. Comparison of crude lysate pellets from isogenic strains of yeast with different prion composition: Identification of prion-associated proteins. ACTA ACUST UNITED AC 2010. [DOI: 10.1134/s1990519x10010049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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10
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Nevzglyadova OV, Artemov AV, Mittenberg AG, Solovyov KV, Kostyleva EI, Mikhailova EV, Kuznetsova IM, Turoverov KK, Soidla TR. Prion-associated proteins in yeast: comparative analysis of isogenic [PSI+] and [psi−] strains. Yeast 2009; 26:611-31. [DOI: 10.1002/yea.1710] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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11
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Bardill JP, Dulle JE, Fisher JR, True HL. Requirements of Hsp104p activity and Sis1p binding for propagation of the [RNQ(+)] prion. Prion 2009; 3:151-60. [PMID: 19770577 DOI: 10.4161/pri.3.3.9662] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The formation and maintenance of prions in the yeast Saccharomyces cerevisiae is highly regulated by the cellular chaperone machinery. The most important player in this regulation is Hsp104p, which is required for the maintenance of all known prions. The requirements for other chaperones, such as members of the Hsp40 or Hsp70 families, vary with each individual prion. [RNQ(+)] cells do not have a phenotype that is amenable to genetic screens to identify cellular factors important in prion propagation. Therefore, we used a chimeric construct that reports the [RNQ(+)] status of cells to perform a screen for mutants that are unable to maintain [RNQ(+)]. We found eight separate mutations in Hsp104p that caused [RNQ(+)] cells to become [rnq(-)]. These mutations also caused the loss of the [PSI(+)] prion. The expression of one of these mutants, Hsp104p-E190K, showed differential loss of the [RNQ(+)] and [PSI(+)] prions in the presence of wild type Hsp104p. Hsp104p-E190K inefficiently propagated [RNQ(+)] and was unable to maintain [PSI(+)]. The mutant was unable to act on other in vivo substrates, as strains carrying it were not thermotolerant. Purified recombinant Hsp104p-E190K showed a reduced level of ATP hydrolysis as compared to wild type protein. This is likely the cause of both prion loss and lack of in vivo function. Furthermore, it suggests that [RNQ(+)] requires less Hsp104p activity to maintain transmissible protein aggregates than Sup35p. Additionally, we show that the L94A mutation in Rnq1p, which reduces its interaction with Sis1p, prevents Rnq1p from maintaining a prion and inducing [PSI(+)].
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Affiliation(s)
- J Patrick Bardill
- Department of Cell Biology & Physiology, Washington University School of Medicine, St. Louis, MO, USA
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12
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Insights into the mechanism of prion propagation. Curr Opin Struct Biol 2008; 18:52-9. [DOI: 10.1016/j.sbi.2007.12.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 12/12/2007] [Accepted: 12/13/2007] [Indexed: 11/23/2022]
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13
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Abstract
Many of the fatal neurodegenerative disorders that plague humankind, including Alzheimer's and Parkinson's disease, are connected with the misfolding of specific proteins into a surprisingly generic fibrous conformation termed amyloid. Prior to amyloid fiber assembly, many proteins populate a common oligomeric conformation, which may be severely cytotoxic. Therapeutic innovations are desperately sought to safely reverse this aberrant protein aggregation and return proteins to normal function. Whether mammalian cells possess any such endogenous activity remains unclear. By contrast, fungi, plants and bacteria all express Hsp104, a protein-remodeling factor, which synergizes with the Hsp70 chaperone system to resolve aggregated proteins and restore their functionality. Surprisingly, amyloids can also be adaptive. In yeast, Hsp104 directly regulates the amyloidogenesis of several prion proteins, which can confer selective advantages. Here, I review the modus operandi of Hsp104 and showcase efforts to unleash Hsp104 on the protein-misfolding events connected to disparate neurodegenerative amyloidoses.
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Affiliation(s)
- James Shorter
- Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6059, USA.
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14
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Chernoff YO. Stress and prions: lessons from the yeast model. FEBS Lett 2007; 581:3695-701. [PMID: 17509571 PMCID: PMC2695654 DOI: 10.1016/j.febslet.2007.04.075] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Revised: 04/20/2007] [Accepted: 04/21/2007] [Indexed: 10/23/2022]
Abstract
Yeast self-perpetuating amyloids (prions) provide a convenient model for studying the cellular control of highly ordered aggregates involved in mammalian protein assembly disorders. The very ability of an amyloid to propagate a prion state in yeast is determined by its interactions with the stress-inducible chaperone Hsp104. Prion formation and propagation are also influenced by other stress-related chaperones (Hsp70 and Hsp40), and by alterations of the protein trafficking and degradation networks. Some stress conditions induce prion formation or loss. It is proposed that prions arise as byproducts of the reversible assembly of highly ordered complexes, protecting certain proteins during unfavorable conditions.
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Affiliation(s)
- Yury O Chernoff
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0230, USA.
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