1
|
Liebold J, Winter R, Golbik R, Hause G, Parthier C, Schwarz E. Conformational stability of the RNP domain controls fibril formation of PABPN1. Protein Sci 2015; 24:1789-99. [PMID: 26267866 DOI: 10.1002/pro.2769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 08/03/2015] [Accepted: 08/04/2015] [Indexed: 11/07/2022]
Abstract
The disease oculopharyngeal muscular dystrophy is caused by alanine codon trinucleotide expansions in the N-terminal segment of the nuclear poly(A) binding protein PABPN1. As histochemical features of the disease, intranuclear inclusions of PABPN1 have been reported. Whereas the purified N-terminal domain of PABPN1 forms fibrils in an alanine-dependent way, fibril formation of the full-length protein occurs also in the absence of alanines. Here, we addressed the question whether the stability of the RNP domain or domain swapping within the RNP domain may add to fibril formation. A variant of full-length PABPN1 with a stabilizing disulfide bond at position 185/201 in the RNP domain fibrillized in a redox-sensitive manner suggesting that the integrity of the RNP domain may contribute to fibril formation. Thermodynamic analysis of the isolated wild-type and the disulfide-linked RNP domain showed two state unfolding/refolding characteristics without detectable intermediates. Quantification of the thermodynamic stability of the mutant RNP domain pointed to an inverse correlation between fibril formation of full-length PABPN1 and the stability of the RNP domain.
Collapse
Affiliation(s)
- Jens Liebold
- Department of Protein Biochemistry, Institute of Biochemistry and Biotechnology, Martin Luther University, Halle Wittenberg, 06120, Halle, Germany
| | - Reno Winter
- Department of Protein Biochemistry, Institute of Biochemistry and Biotechnology, Martin Luther University, Halle Wittenberg, 06120, Halle, Germany
| | - Ralph Golbik
- Department of Virology, Institute of Biochemistry and Biotechnology, Martin Luther University, Halle Wittenberg, 06120, Halle, Germany
| | - Gerd Hause
- Biocenter, Martin Luther University, Halle Wittenberg, 06120, Halle, Germany
| | - Christoph Parthier
- Department of Physical Biotechnology, Institute of Biochemistry and Biotechnology, Martin Luther University, Halle Wittenberg, 06120, Halle, Germany
| | - Elisabeth Schwarz
- Department of Protein Biochemistry, Institute of Biochemistry and Biotechnology, Martin Luther University, Halle Wittenberg, 06120, Halle, Germany
| |
Collapse
|
2
|
Buttstedt A, Wostradowski T, Ihling C, Hause G, Sinz A, Schwarz E. Different morphology of amyloid fibrils originating from agitated and non-agitated conditions. Amyloid 2013; 20:86-92. [PMID: 23570235 DOI: 10.3109/13506129.2013.784962] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In vitro amyloid formation has been suggested to be a common property of any polypeptide chain depending on particular environmental conditions although in vivo amyloid fibril formation can be promoted by point mutations or triplet expansions. Here, we explored the influence of agitation on fibril formation of amyloidogenic alanine segments fused to Cold Shock Protein B (CspB) of Bacillus subtilis. While without agitation fibril formation was clearly dependent on the presence of an amyloidogenic alanine segment, fibril formation was independent of the amyloidogenic segment under agitation. Agitation even led to fibrillation of native CspB lacking the amyloidogenic segment. Furthermore, agitation not only influenced the kinetics of fibril formation, but also resulted in completely different fibril morphologies. These results indicate that experimental conditions can alter the region that undergoes a conformational change during in vitro fibrillation. Moreover, the data show that deductions from in vitro assays on in vivo fibril formation mechanisms are afflicted with a certain degree of uncertainty and therefore need to be cautiously discussed.
Collapse
Affiliation(s)
- Anja Buttstedt
- Facultatea de Zootehnie şi Biotehnologii, Universitatea de Ştiinţe Agricole şi Medicină Veterinară, Calea Mănăştur 3-5, 400372 Cluj-Napoca, Romania.
| | | | | | | | | | | |
Collapse
|
3
|
Banerjee A, Apponi LH, Pavlath GK, Corbett AH. PABPN1: molecular function and muscle disease. FEBS J 2013; 280:4230-50. [PMID: 23601051 DOI: 10.1111/febs.12294] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 04/03/2013] [Accepted: 04/11/2013] [Indexed: 12/17/2022]
Abstract
The polyadenosine RNA binding protein polyadenylate-binding nuclear protein 1 (PABPN1) plays key roles in post-transcriptional processing of RNA. Although PABPN1 is ubiquitously expressed and presumably contributes to control of gene expression in all tissues, mutation of the PABPN1 gene causes the disease oculopharyngeal muscular dystrophy (OPMD), in which a limited set of skeletal muscles are affected. A major goal in the field of OPMD research is to understand why mutation of a ubiquitously expressed gene leads to a muscle-specific disease. PABPN1 plays a well-documented role in controlling the poly(A) tail length of RNA transcripts but new functions are emerging through studies that exploit a variety of unbiased screens as well as model organisms. This review addresses (a) the molecular function of PABPN1 incorporating recent findings that reveal novel cellular functions for PABPN1 and (b) the approaches that are being used to understand the molecular defects that stem from expression of mutant PABPN1. The long-term goal in this field of research is to understand the key molecular functions of PABPN1 in muscle as well as the mechanisms that underlie the pathological consequences of mutant PABPN1. Armed with this information, researchers can seek to develop therapeutic approaches to enhance the quality of life for patients afflicted with OPMD.
Collapse
Affiliation(s)
- Ayan Banerjee
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | | | | |
Collapse
|
4
|
Winter R, Kühn U, Hause G, Schwarz E. Polyalanine-independent conformational conversion of nuclear poly(A)-binding protein 1 (PABPN1). J Biol Chem 2012; 287:22662-71. [PMID: 22570486 DOI: 10.1074/jbc.m112.362327] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Oculopharyngeal muscular dystrophy is a late-onset disease caused by an elongation of a natural 10-alanine segment within the N-terminal domain of the nuclear poly(A)-binding protein 1 (PABPN1) to maximally 17 alanines. The disease is characterized by intranuclear deposits consisting primarily of PABPN1. In previous studies, we could show that the N-terminal domain of PABPN1 forms amyloid-like fibrils. Here, we analyze fibril formation of full-length PABPN1. Unexpectedly, fibril formation was independent of the presence of the alanine segment. With regard to fibril formation kinetics and resistance against denaturants, fibrils formed by full-length PABPN1 had completely different properties from those formed by the N-terminal domain. Fourier transformed infrared spectroscopy and limited proteolysis showed that fibrillar PABPN1 has a structure that differs from native PABPN1. Circumstantial evidence is presented that the C-terminal domain is involved in fibril formation.
Collapse
Affiliation(s)
- Reno Winter
- Institute for Biochemistry and Biotechnology, Technical Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | | | | | | |
Collapse
|
5
|
Haupt C, Bereza M, Kumar ST, Kieninger B, Morgado I, Hortschansky P, Fritz G, Röcken C, Horn U, Fändrich M. Pattern Recognition with a Fibril-Specific Antibody Fragment Reveals the Surface Variability of Natural Amyloid Fibrils. J Mol Biol 2011; 408:529-40. [DOI: 10.1016/j.jmb.2011.02.032] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 01/24/2011] [Accepted: 02/13/2011] [Indexed: 10/18/2022]
|
6
|
Barbezier N, Chartier A, Bidet Y, Buttstedt A, Voisset C, Galons H, Blondel M, Schwarz E, Simonelig M. Antiprion drugs 6-aminophenanthridine and guanabenz reduce PABPN1 toxicity and aggregation in oculopharyngeal muscular dystrophy. EMBO Mol Med 2011; 3:35-49. [PMID: 21204267 PMCID: PMC3044817 DOI: 10.1002/emmm.201000109] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is an adult-onset syndrome characterized by progressive degeneration of specific muscles. OPMD is caused by extension of a polyalanine tract in poly(A) binding protein nuclear 1 (PABPN1). Insoluble nuclear inclusions form in diseased muscles. We have generated a Drosophila model of OPMD that recapitulates the features of the disorder. Here, we show that the antiprion drugs 6-aminophenanthridine (6AP) and guanabenz acetate (GA), which prevent formation of amyloid fibers by prion proteins in cell models, alleviate OPMD phenotypes in Drosophila, including muscle degeneration and nuclear inclusion formation. The large ribosomal RNA and its activity in protein folding were recently identified as a specific cellular target of 6AP and GA. We show that deletions of the ribosomal DNA locus reduce OPMD phenotypes and act synergistically with sub-effective doses of 6AP. In a complementary approach, we demonstrate that ribosomal RNA accelerates in vitro fibril formation of PABPN1 N-terminal domain. These results reveal the conserved role of ribosomal RNA in different protein aggregation disorders and identify 6AP and GA as general anti-aggregation molecules.
Collapse
Affiliation(s)
- Nicolas Barbezier
- mRNA Regulation and Development, Institut de Génétique Humaine, CNRS UPR 1142, Montpellier Cedex 5, France
| | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Affiliation(s)
- Bernard Brais
- Laboratory of Neurogenetics of Motion, Faculté de Médecine de l'Université de Montréal, Centre de Recherche cu CHUM, Hôpital Notre-Dame-CHUM, Montréal, Québec, Canada.
| |
Collapse
|
8
|
Influence of the stability of a fused protein and its distance to the amyloidogenic segment on fibril formation. PLoS One 2010; 5:e15436. [PMID: 21124848 PMCID: PMC2990761 DOI: 10.1371/journal.pone.0015436] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 09/21/2010] [Indexed: 11/19/2022] Open
Abstract
Conversion of native proteins into amyloid fibrils is irreversible and therefore it is difficult to study the interdependence of conformational stability and fibrillation by thermodynamic analyses. Here we approached this problem by fusing amyloidogenic poly-alanine segments derived from the N-terminal domain of the nuclear poly (A) binding protein PABPN1 with a well studied, reversibly unfolding protein, CspB from Bacillus subtilis. Earlier studies had indicated that CspB could maintain its folded structure in fibrils, when it was separated from the amyloidogenic segment by a long linker. When CspB is directly fused with the amyloidogenic segment, it unfolds because its N-terminal chain region becomes integrated into the fibrillar core, as shown by protease mapping experiments. Spacers of either 3 or 16 residues between CspB and the amyloidogenic segment were not sufficient to prevent this loss of CspB structure. Since the low thermodynamic stability of CspB (ΔG(D) = 12.4 kJ/mol) might be responsible for unfolding and integration of CspB into fibrils, fusions with a CspB mutant with enhanced thermodynamic stability (ΔG(D) = 26.9 kJ/mol) were studied. This strongly stabilized CspB remained folded and prevented fibril formation in all fusions. Our data show that the conformational stability of a linked, independently structured protein domain can control fibril formation.
Collapse
|
9
|
Abstract
It has been 10 years since the identification of the first PABPN1 gene (GCN)(n)/polyalanine mutations responsible for oculopharyngeal muscular dystrophy (OPMD). These mutations have been found in most cases of OPMD diagnosed in more than 35 countries. Sequence analyses have shown that such mutations have occurred numerous times in human history. Although PABPN1 was found early on to be a component of the classic filamentous intranuclear inclusions (INIs), mRNA and other proteins also have been found to coaggregate in the INIs. It is still unclear if the INIs play a pathologic or a protective role. The generation of numerous cell and animal models of OPMD has led to greater insight into its complex molecular pathophysiology and identified the first candidate therapeutic molecules. This paper reviews basic and clinical research on OPMD, with special emphasis on recent developments in the understanding of its pathophysiology.
Collapse
|
10
|
Sackewitz M, Scheidt HA, Lodderstedt G, Schierhorn A, Schwarz E, Huster D. Structural and Dynamical Characterization of Fibrils from a Disease-Associated Alanine Expansion Domain Using Proteolysis and Solid-State NMR Spectroscopy. J Am Chem Soc 2008; 130:7172-3. [DOI: 10.1021/ja800120s] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mirko Sackewitz
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany, Max Planck Research Unit for Enzymology of Protein Folding, D-06120 Halle, Germany, and Institute of Medical Physics and Biophysics, D-04107 Leipzig, Germany
| | - Holger A. Scheidt
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany, Max Planck Research Unit for Enzymology of Protein Folding, D-06120 Halle, Germany, and Institute of Medical Physics and Biophysics, D-04107 Leipzig, Germany
| | - Grit Lodderstedt
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany, Max Planck Research Unit for Enzymology of Protein Folding, D-06120 Halle, Germany, and Institute of Medical Physics and Biophysics, D-04107 Leipzig, Germany
| | - Angelika Schierhorn
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany, Max Planck Research Unit for Enzymology of Protein Folding, D-06120 Halle, Germany, and Institute of Medical Physics and Biophysics, D-04107 Leipzig, Germany
| | - Elisabeth Schwarz
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany, Max Planck Research Unit for Enzymology of Protein Folding, D-06120 Halle, Germany, and Institute of Medical Physics and Biophysics, D-04107 Leipzig, Germany
| | - Daniel Huster
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany, Max Planck Research Unit for Enzymology of Protein Folding, D-06120 Halle, Germany, and Institute of Medical Physics and Biophysics, D-04107 Leipzig, Germany
| |
Collapse
|
11
|
Sackewitz M, von Einem S, Hause G, Wunderlich M, Schmid FX, Schwarz E. A folded and functional protein domain in an amyloid-like fibril. Protein Sci 2008; 17:1044-54. [PMID: 18424511 DOI: 10.1110/ps.073276308] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The effect of the polypeptide environment on polyalanine-induced fibril formation was investigated with amyloidogenic fragments from PAPBN1, a nuclear protein controlling polyadenylation. Mutation-caused extensions of the natural 10 alanine sequence up to maximally 17 alanines result in fibril formation of PABPN1 and the development of the disease oculopharyngeal muscular dystrophy (OPMD). We explored the influence of fibril formation on the structure and function of a one-domain protein linked to the fibril-forming part of PABPN1. The well-characterized, stably folded, one-domain protein, cold-shock protein CspB from Bacillus subtilis, was fused either to the C terminus of the entire N-terminal domain of PABPN1 or directly to peptides consisting of 10 or 17 alanine residues. The fusion protein between the N-terminal domain of PABPN1 and CspB formed fibrils in which the structure and activity of CspB were retained. In the fibrils formed by fusions in which the polyalanine sequence was directly linked to CspB, CspB was unfolded. These results indicate that the folded conformation and the function of a protein domain can be maintained in amyloid-like fibrils, and that the distance between this domain and the fibril plays an important role.
Collapse
Affiliation(s)
- Mirko Sackewitz
- Institut für Biochemie und Biotechnologie, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle, Germany
| | | | | | | | | | | |
Collapse
|
12
|
Monitoring fibril formation of the N-terminal domain of PABPN1 carrying an alanine repeat by tryptophan fluorescence and real-time NMR. FEBS Lett 2008; 582:1587-92. [PMID: 18406354 DOI: 10.1016/j.febslet.2008.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Revised: 04/02/2008] [Accepted: 04/02/2008] [Indexed: 11/21/2022]
Abstract
Intranuclear fibrils due to poly-alanine expansions in the N-terminal domain of the poly(A) binding protein PABPN1 correlate with the disease oculopharyngeal muscular dystrophy (OPMD). For monitoring fibril formation by fluorescence and real-time NMR spectroscopy, tryptophans were introduced either into the middle or C-terminal of the poly-alanine segment. The kinetics of fibril formation which were monitored by fluorescence spectroscopy were matched by real-time NMR kinetics. Our results show that fibril formation is concomitant with the burial of the tryptophans in the fibrillar core. Since no soluble pre-fibrillar intermediate(s) was detected, fibril formation of this domain may be regarded as a two state conversion from an unfolded soluble into folded insoluble species.
Collapse
|
13
|
Lodderstedt G, Sachs R, Faust J, Bordusa F, Kühn U, Golbik R, Kerth A, Wahle E, Balbach J, Schwarz E. Hofmeister salts and potential therapeutic compounds accelerate in vitro fibril formation of the N-terminal domain of PABPN1 containing a disease-causing alanine extension. Biochemistry 2008; 47:2181-9. [PMID: 18205394 DOI: 10.1021/bi701322g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The analysis of modulation of fibril formation helps to understand the mechanism of fibrillation processes besides opening routes for therapeutic intervention. Fibril formation was investigated with the N-terminal domain of the nuclear poly-A binding protein PABPN1, a protein in which mutation-based alanine extensions lead to the disease oculopharyngeal muscular dystrophy (OPMD). The disease is characterized by fibrillar inclusions consisting mainly of PABPN1. A systematic modulation of fibril formation kinetics was studied with trifluoroethanol, inorganic salts, low molecular weight organic substances, a poly-alanine peptide and anti-amyloidogenic compounds. Anions with salting out properties at high molar concentrations, poly-ethylene glycol and the poly-alanine peptide enhanced fibril formation rates. The effect of l-arginine on fibrillation rates depended on the counterion. Doxycycline and trehalose, compounds that have been found to mitigate OPMD symptoms in animal models, surprisingly accelerated fibril formation. Our results suggest that in the case of salts, primarily the salting out effects rather than electrostatic effects modulate fibril formation. The unexpected acceleration of fibril formation by trehalose and doxycycline questions the general view that these compounds per se impair fibril formation.
Collapse
Affiliation(s)
- Grit Lodderstedt
- Institute for Biochemistry and Biotechnology of the Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Strasse 3, 06120 Halle, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|