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Carlsson A, Axell E, Emanuelsson C, Olsson U, Linse S. The Ability of DNAJB6b to Suppress Amyloid Formation Depends on the Chaperone Aggregation State. ACS Chem Neurosci 2024; 15:1732-1737. [PMID: 38640082 DOI: 10.1021/acschemneuro.4c00120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2024] Open
Abstract
For many chaperones, a propensity to self-assemble correlates with function. The highly efficient amyloid suppressing chaperone DNAJB6b has been reported to oligomerize. A key question is whether the DNAJB6b self-assemblies or their subunits are active units in the suppression of amyloid formation. Here, we address this question using a nonmodified chaperone. We use the well-established aggregation kinetics of the amyloid β 42 peptide (Aβ42) as a readout of the amyloid suppression efficiency. The experimental setup relies on the slow dissociation of DNAJB6b assemblies upon dilution. We find that the dissociation of the chaperone assemblies correlates with its ability to suppress fibril formation. Thus, the data show that the subunits of DNAJB6b assemblies rather than the large oligomers are the active forms in amyloid suppression. Our results provide insights into how DNAJB6b operates as a chaperone and illustrate the importance of established assembly equilibria and dissociation rates for the design of kinetic experiments.
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Affiliation(s)
- Andreas Carlsson
- Lund University, Biochemistry and Structural Biology, Lund, Naturvetarvägen 16, 223 62, Sweden
| | - Emil Axell
- Lund University, Biochemistry and Structural Biology, Lund, Naturvetarvägen 16, 223 62, Sweden
| | - Cecilia Emanuelsson
- Lund University, Biochemistry and Structural Biology, Lund, Naturvetarvägen 16, 223 62, Sweden
| | - Ulf Olsson
- Lund University, Physical Chemistry, Lund, Naturvetarvägen 16, 223 62, Sweden
| | - Sara Linse
- Lund University, Biochemistry and Structural Biology, Lund, Naturvetarvägen 16, 223 62, Sweden
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Lindberg M, Axell E, Sparr E, Linse S. A label-free high-throughput protein solubility assay and its application to Aβ40. Biophys Chem 2024; 307:107165. [PMID: 38309218 DOI: 10.1016/j.bpc.2023.107165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/18/2023] [Accepted: 12/25/2023] [Indexed: 02/05/2024]
Abstract
A major hallmark of Alzheimer's disease is the accumulation of aggregated amyloid β peptide (Aβ) in the brain. Here we develop a solubility assay for proteins and measure the solubility of Aβ40. In brief, the method utilizes 96-well filter plates to separate monomeric Aβ from aggregated Aβ, and the small species are quantified with the amine reactive dye o-phthalaldehyde (OPA). This procedure ensures that solubility is measured for unlabeled species, and makes the assay high-throughput and inexpensive. We demonstrate that the filter plates successfully separate fibrils from monomer, with negligible monomer adsorption, and that OPA can quantify Aβ peptides in a concentration range from 40 nM to 20 μM. We also show that adding a methionine residue to the N-terminus of Aβ1-40 decreases the solubility by <3-fold. The method will facilitate further solubility studies, and contribute to the understanding of the thermodynamics of amyloid fibril formation.
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Affiliation(s)
- Max Lindberg
- Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - Emil Axell
- Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - Emma Sparr
- Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden
| | - Sara Linse
- Biochemistry and Structural Biology, Lund University, Lund, Sweden.
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Axell E, Sparr E, Linse S. Solubility of the amyloidogenic core of tau in CSF. Biophys J 2023; 122:9a. [PMID: 36785123 DOI: 10.1016/j.bpj.2022.11.280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Emil Axell
- Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - Emma Sparr
- Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden
| | - Sara Linse
- Biochemistry and Structural Biology, Lund University, Lund, Sweden
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Rodriguez Camargo DC, Sileikis E, Chia S, Axell E, Bernfur K, Cataldi RL, Cohen SIA, Meisl G, Habchi J, Knowles TPJ, Vendruscolo M, Linse S. Proliferation of Tau 304-380 Fragment Aggregates through Autocatalytic Secondary Nucleation. ACS Chem Neurosci 2021; 12:4406-4415. [PMID: 34783519 PMCID: PMC8640994 DOI: 10.1021/acschemneuro.1c00454] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
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The self-assembly
of the protein tau into neurofibrillary tangles
is one of the hallmarks of Alzheimer’s disease and related
tauopathies. Still, the molecular mechanism of tau aggregation is
largely unknown. This problem may be addressed by systematically obtaining
reproducible in vitro kinetics measurements under quiescent conditions
in the absence of triggering substances. Here, we implement this strategy
by developing protocols for obtaining an ultrapure tau fragment (residues
304–380 of tau441) and for performing spontaneous aggregation
assays with reproducible kinetics under quiescent conditions. We are
thus able to identify the mechanism of fibril formation of the tau
304–380 fragment at physiological pH using fluorescence spectroscopy
and mass spectrometry. We find that primary nucleation is slow, and
that secondary processes dominate the aggregation process once the
initial aggregates are formed. Moreover, our results further show
that secondary nucleation of monomers on fibril surfaces dominates
over fragmentation of fibrils. Using separate isotopes in monomers
and fibrils, through mass spectroscopy measurements, we verify the
isotope composition of the intermediate oligomeric species, which
reveals that these small aggregates are generated from monomer through
secondary nucleation. Our results provide a framework for understanding
the processes leading to tau aggregation in disease and for selecting
possible tau forms as targets in the development of therapeutic interventions
in Alzheimer’s disease.
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Affiliation(s)
- Diana C. Rodriguez Camargo
- Department of Biochemistry and Structural Biology, Chemical Centre, Lund University, SE-221 00 Lund, Sweden
- Wren Therapeutics Limited, Clarendon House, Clarendon Road, Cambridge CB2 8FH, United Kingdom
| | - Eimantas Sileikis
- Wren Therapeutics Limited, Clarendon House, Clarendon Road, Cambridge CB2 8FH, United Kingdom
| | - Sean Chia
- Wren Therapeutics Limited, Clarendon House, Clarendon Road, Cambridge CB2 8FH, United Kingdom
| | - Emil Axell
- Department of Biochemistry and Structural Biology, Chemical Centre, Lund University, SE-221 00 Lund, Sweden
| | - Katja Bernfur
- Department of Biochemistry and Structural Biology, Chemical Centre, Lund University, SE-221 00 Lund, Sweden
| | - Rodrigo L. Cataldi
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - Samuel I. A. Cohen
- Wren Therapeutics Limited, Clarendon House, Clarendon Road, Cambridge CB2 8FH, United Kingdom
| | - Georg Meisl
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - Johnny Habchi
- Wren Therapeutics Limited, Clarendon House, Clarendon Road, Cambridge CB2 8FH, United Kingdom
| | - Tuomas P. J. Knowles
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - Sara Linse
- Department of Biochemistry and Structural Biology, Chemical Centre, Lund University, SE-221 00 Lund, Sweden
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