1
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Koroleva ON, Kuzmina NV, Dubrovin EV, Drutsa VL. Atomic force microscopy of spherical intermediates on the pathway to fibril formation of influenza A virus nuclear export protein. Microsc Res Tech 2024; 87:1131-1145. [PMID: 38270267 DOI: 10.1002/jemt.24499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 01/02/2024] [Accepted: 01/07/2024] [Indexed: 01/26/2024]
Abstract
The nuclear export protein of the influenza A virus (NEP) is involved in many important processes of the virus life cycle. This makes it an attractive target for the treatment of a disease caused by a virus. Previously it has been shown, that recombinant variants of NEP are highly prone to aggregation in solution under various conditions with the formation of amyloid-like aggregates. In the present work, the amyloid nature of NEP aggregates was evidenced by Congo red binding assays. Atomic force microscopy has shown that NEP can form two types of spherical nanoparticles, which provide an alternative pathway for the formation of amyloid-like fibrils. Type I of these "fibrillogenic" spheres, formed under physiological conditions, represents the micelle-like particles with height 10-60 nm, which can generate worm-like flexible fibrils with the diameter 2.5-4.0 nm, length 20-500 nm and the Young's modulus ~73 MPa. Type II spherical aggregates with size of about 400-1000 nm, formed at elevated temperatures, includes fractions of drop-like and vesicle-like particles, generating more rigid amyloid-like fibrils with height of ~8 nm, and length of up to 2 μm. The hypothetical mechanism of fibril formation via nanospherical structures was suggested. RESEARCH HIGHLIGHTS: AFM has revealed two types of the influenza A virus nuclear export protein spherical aggregates. They provide an alternative pathway for the formation of amyloid-like fibrils. The mechanism of fibril formation via spherical structures is suggested.
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Affiliation(s)
- Olga N Koroleva
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Natalia V Kuzmina
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russian Federation
| | - Evgeniy V Dubrovin
- Faculty of Physics, Lomonosov Moscow State University, Moscow, Russian Federation
- National University of Science and Technology, MISIS, Moscow, Russian Federation
| | - Valeriy L Drutsa
- A.N.Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
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2
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Fu Q, Zhang B, Chen X, Chu L. Liquid-liquid phase separation in Alzheimer's disease. J Mol Med (Berl) 2024; 102:167-181. [PMID: 38167731 DOI: 10.1007/s00109-023-02407-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 11/26/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024]
Abstract
The pathological aggregation and misfolding of tau and amyloid-β play a key role in Alzheimer's disease (AD). However, the underlying pathological mechanisms remain unclear. Emerging evidences indicate that liquid-liquid phase separation (LLPS) has great impacts on regulating human health and diseases, especially neurodegenerative diseases. A series of studies have revealed the significance of LLPS in AD. In this review, we summarize the latest progress of LLPS in AD, focusing on the impact of metal ions, small-molecule inhibitors, and proteinaceous partners on tau LLPS and aggregation, as well as toxic oligomerization, the role of LLPS on amyloid-β (Aβ) aggregation, and the cross-interactions between amyloidogenic proteins in AD. Eventually, the fundamental methods and techniques used in LLPS study are introduced. We expect to present readers a deeper understanding of the relationship between LLPS and AD.
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Affiliation(s)
- Qinggang Fu
- Hepatic Surgery Center and Hubei Key Laboratory of Hepato-Pancreatic-Biliary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Bixiang Zhang
- Hepatic Surgery Center and Hubei Key Laboratory of Hepato-Pancreatic-Biliary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Xiaoping Chen
- Hepatic Surgery Center and Hubei Key Laboratory of Hepato-Pancreatic-Biliary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Liang Chu
- Hepatic Surgery Center and Hubei Key Laboratory of Hepato-Pancreatic-Biliary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China.
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3
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Cascella R, Banchelli M, Abolghasem Ghadami S, Ami D, Gagliani MC, Bigi A, Staderini T, Tampellini D, Cortese K, Cecchi C, Natalello A, Adibi H, Matteini P, Chiti F. An in situ and in vitro investigation of cytoplasmic TDP-43 inclusions reveals the absence of a clear amyloid signature. Ann Med 2023; 55:72-88. [PMID: 36495262 PMCID: PMC9746631 DOI: 10.1080/07853890.2022.2148734] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Introduction: Several neurodegenerative conditions are associated with a common histopathology within neurons of the central nervous system, consisting of the deposition of cytoplasmic inclusions of TAR DNA-binding protein 43 (TDP-43). Such inclusions have variably been described as morphologically and molecularly ordered aggregates having amyloid properties, as filaments without the cross-β-structure and dye binding specific for amyloid, or as amorphous aggregates with no defined structure and fibrillar morphology.Aims and Methods: Here we have expressed human full-length TDP-43 in neuroblastoma x spinal cord 34 (NSC-34) cells to investigate the morphological, structural, and tinctorial properties of TDP-43 inclusions in situ. We have used last-generation amyloid diagnostic probes able to cross the cell membrane and detect amyloid in the cytoplasm and have adopted Raman and Fourier transform infrared microspectroscopies to study in situ the secondary structure of the TDP-43 protein in the inclusions. We have then used transmission electron microscopy to study the morphology of the TDP-43 inclusions.Results: The results show the absence of amyloid dye binding, the lack of an enrichment of cross-β structure in the inclusions, and of a fibrillar texture in the round inclusions. The aggregates formed in vitro from the purified protein under conditions in which it is initially native also lack all these characteristics, ruling out a clear amyloid-like signature.Conclusions: These findings indicate a low propensity of TDP-43 to form amyloid fibrils and even non-amyloid filaments, under conditions in which the protein is initially native and undergoes its typical nucleus-to-cell mislocalization. It cannot be excluded that filaments emerge on the long time scale from such inclusions, but the high propensity of the protein to form initially other types of inclusions appear to be an essential characteristic of TDP-43 proteinopathies.KEY MESSAGESCytoplasmic inclusions of TDP-43 formed in NSC-34 cells do not stain with amyloid-diagnostic dyes, are not enriched with cross-β structure, and do not show a fibrillar morphology.TDP-43 assemblies formed in vitro from pure TDP-43 do not have any hallmarks of amyloid.
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Affiliation(s)
- Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Martina Banchelli
- Institute of Applied Physics "Nello Carrara", National Research Council, Sesto Fiorentino, Italy
| | | | - Diletta Ami
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan, Italy.,Milan Center of Neuroscience (NeuroMI), Milan, Italy
| | - Maria Cristina Gagliani
- Cellular Electron Microscopy Laboratory, Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Tommaso Staderini
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Davide Tampellini
- U 1195 INSERM-Université Paris-Saclay, Paris, France.,Institut Professeur Baulieu, Paris, France
| | - Katia Cortese
- Cellular Electron Microscopy Laboratory, Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Antonino Natalello
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan, Italy.,Milan Center of Neuroscience (NeuroMI), Milan, Italy
| | - Hadi Adibi
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Paolo Matteini
- Institute of Applied Physics "Nello Carrara", National Research Council, Sesto Fiorentino, Italy
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
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4
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Doke AA, Jha SK. Shapeshifter TDP-43: Molecular mechanism of structural polymorphism, aggregation, phase separation and their modulators. Biophys Chem 2023; 295:106972. [PMID: 36812677 DOI: 10.1016/j.bpc.2023.106972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/09/2023] [Accepted: 02/12/2023] [Indexed: 02/17/2023]
Abstract
TDP-43 is a nucleic acid-binding protein that performs physiologically essential functions and is known to undergo phase separation and aggregation during stress. Initial observations have shown that TDP-43 forms heterogeneous assemblies, including monomer, dimer, oligomers, aggregates, phase-separated assemblies, etc. However, the significance of each assembly of TDP-43 concerning its function, phase separation, and aggregation is poorly known. Furthermore, how different assemblies of TDP-43 are related to each other is unclear. In this review, we focus on the various assemblies of TDP-43 and discuss the plausible origin of the structural heterogeneity of TDP-43. TDP-43 is involved in multiple physiological processes like phase separation, aggregation, prion-like seeding, and performing physiological functions. However, the molecular mechanism behind the physiological process performed by TDP-43 is not well understood. The current review discusses the plausible molecular mechanism of phase separation, aggregation, and prion-like propagation of TDP-43.
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Affiliation(s)
- Abhilasha A Doke
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Santosh Kumar Jha
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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5
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Role of Triggers on the Structural and Functional Facets of TAR DNA-binding Protein 43. Neuroscience 2023; 511:110-130. [PMID: 36442745 DOI: 10.1016/j.neuroscience.2022.11.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 09/15/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022]
Abstract
Nuclear TAR DNA-binding protein 43 (TDP-43) mitigates cellular function, but the dynamic nucleus-cytoplasm shuttling of TDP-43 is disrupted in diseases, such as Amyotrophic Lateral Sclerosis (ALS). The polymorphic nature of the TDP-43 structures in vitro and in vivo is a result of environmental factors leading to the protein pathogenesis. Once the triggers which mitigate TDP-43 biochemistry are identified, new therapies can be developed. This review aims to illustrate recent discoveries in the diversity of TDP-43 structures (amyloidogenic and non-amyloidogenic) and highlight the triggers which result in their formation.
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6
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Staderini T, Bigi A, Mongiello D, Cecchi C, Chiti F. Biophysical characterization of full-length TAR DNA-binding protein (TDP-43) phase separation. Protein Sci 2022; 31:e4509. [PMID: 36371546 PMCID: PMC9703588 DOI: 10.1002/pro.4509] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 10/17/2022] [Accepted: 11/05/2022] [Indexed: 11/15/2022]
Abstract
Amyotrophic lateral sclerosis and frontotemporal lobar degeneration with ubiquitin-positive inclusions are associated with deposition of cytosolic inclusion bodies of TAR DNA-binding protein 43 (TDP-43) in brain and motor neurons. We induced phase separation of purified full-length TDP-43 devoid of large tags using a solution-jump method, and monitored it with an array of biophysical techniques. The tetramethylrhodamine-5-maleimide- or Alexa488-labeled protein formed rapidly (<1 min) apparently round, homogeneous and 0.5-1.0 μm wide assemblies, when imaged using confocal fluorescence, bright-field, and stimulated emission depletion microscopy. The assemblies, however, had limited internal diffusion, as assessed with fluorescence recovery after photobleaching, and did not coalesce, but rather clustered into irregular bunches, unlike those formed by the C-terminal domain. They were enriched with α-helical structure, with minor contributions of β-sheet/random structure, had a red-shifted tryptophan fluorescence and did not bind thioflavin T. By monitoring with turbidimetry both the formation of the spherical species and their further clustering under different experimental conditions, we carried out a multiparametric analysis of the two phenomena. In particular, both processes were found to be promoted by high protein concentrations, salts, crowding agents, weakly by reducing agents, as the pH approached a value of 6.0 from either side (corresponding to the TDP-43 isoionic point), and as the temperature approached a value of 31°C from either side. Important differences were found with respect to the TDP-43 C-terminal domain. Our multiparametric results also provide explanations to some of the solubility data obtained on full-length TDP-43 that were difficult to explain following the multiparametric analysis acquired on the C-terminal domain.
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Affiliation(s)
- Tommaso Staderini
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”University of FlorenceFlorenceItaly
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”University of FlorenceFlorenceItaly
| | - Daniele Mongiello
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”University of FlorenceFlorenceItaly
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”University of FlorenceFlorenceItaly
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”University of FlorenceFlorenceItaly
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7
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Nirwal S, Saravanan P, Bajpai A, Meshram VD, Raju G, Deeksha W, Prabusankar G, Patel BK. In Vitro Interaction of a C-Terminal Fragment of TDP-43 Protein with Human Serum Albumin Modulates Its Aggregation. J Phys Chem B 2022; 126:9137-9151. [PMID: 36326054 DOI: 10.1021/acs.jpcb.2c04469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
An increased level of naturally occurring anti-TDP-43 antibodies was observed in the serum and cerebrospinal fluid (CSF) of amyotrophic lateral sclerosis patients. Human serum albumin (HSA), the most abundant protein in blood plasma and CSF, is found to interact with pathological proteins like Aβ and α-synuclein. Therefore, we examined the effect on the in vitro aggregation of a C-terminal fragment of TDP-43 in the presence of HSA. We found that the lag phase in TDP-432C aggregation is abrogated in the presence of HSA, but there is an overall decreased aggregation as examined by thioflavin-T fluorescence spectroscopy and microscopy. An early onset of TDP-432C oligomer formation in the presence of HSA was observed using atomic force microscopy and transmission electron microscopy. Also, a known chemical inhibitor of TDP-432Caggregation, AIM4, abolishes the HSA-induced early formation of TDP-432C oligomers. Notably, the aggregates of TDP-432C formed in the presence of HSA are more stable against sarkosyl detergent. Using affinity copurification, we observed that HSA can bind to TDP-432C, and biolayer interferometry further supported their physical interaction and suggested the binding affinity to be in sub-micromolar range. Taken together, the data support that HSA can interact with TDP-432C in vitro and affect its aggregation.
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Affiliation(s)
- Sadhana Nirwal
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana 502284, India
| | - Preethi Saravanan
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana 502284, India
| | - Akarsh Bajpai
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana 502284, India
| | - Vini D Meshram
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana 502284, India
| | - Gembali Raju
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi Sangareddy, Telangana 502284, India
| | - Waghela Deeksha
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana 502284, India
| | - Ganesan Prabusankar
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi Sangareddy, Telangana 502284, India
| | - Basant K Patel
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana 502284, India
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8
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Cascella R, Bigi A, Riffert DG, Gagliani MC, Ermini E, Moretti M, Cortese K, Cecchi C, Chiti F. A quantitative biology approach correlates neuronal toxicity with the largest inclusions of TDP-43. SCIENCE ADVANCES 2022; 8:eabm6376. [PMID: 35895809 PMCID: PMC9328675 DOI: 10.1126/sciadv.abm6376] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A number of neurodegenerative conditions are associated with the formation of cytosolic inclusions of TDP-43 within neurons. We expressed full-length TDP-43 in a motoneuron/neuroblastoma hybrid cell line (NSC-34) and exploited the high-resolution power of stimulated emission depletion microscopy to monitor the changes of nuclear and cytoplasmic TDP-43 levels and the formation of various size classes of cytoplasmic TDP-43 aggregates with time. Concomitantly, we monitored oxidative stress and mitochondrial impairment using the MitoSOX and MTT reduction assays, respectively. Using a quantitative biology approach, we attributed neuronal dysfunction associated with cytoplasmic deposition component to the formation of the largest inclusions, independently of stress granules. This is in contrast to other neurodegenerative diseases where toxicity is attributed to small oligomers. Using specific inhibitors, markers, and electron microscopy, the proteasome and autophagy were found to target mainly the largest deleterious inclusions, but their efficiency soon decreases without full recovery of neuronal viability.
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Affiliation(s)
- Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
| | - Dylan Giorgino Riffert
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
| | - Maria Cristina Gagliani
- Department of Experimental Medicine, Cellular Electron Microscopy Laboratory, University of Genova, 16132 Genova, Italy
| | - Emilio Ermini
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
| | - Matteo Moretti
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
| | - Katia Cortese
- Department of Experimental Medicine, Cellular Electron Microscopy Laboratory, University of Genova, 16132 Genova, Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
- Corresponding author. (C.C.); (F.C.)
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
- Corresponding author. (C.C.); (F.C.)
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9
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Doke AA, Jha SK. Effect of In Vitro Solvation Conditions on Inter- and Intramolecular Assembly of Full-Length TDP-43. J Phys Chem B 2022; 126:4799-4813. [PMID: 35758053 DOI: 10.1021/acs.jpcb.2c02203] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cellular stress is a major cause of neurodegenerative diseases. In particular, in amyotrophic lateral sclerosis (ALS), around 90% of the cases are believed to occur due to aggregation and misfolding of TDP-43 protein in neurons due to aging and chronic environmental stress. However, the physicochemical basis of how TDP-43 senses the change in solvation conditions during stress and misfolds remains very poorly understood. We show here that the full-length human TDP-43 can exist in equilibrium with multiple structural states. The equilibrium between these states is highly sensitive to changes in solvation conditions. We show that upon thermal and pH stress, amyloidogenic oligomers can form amyloid-like fibrils. However, the internal structure of the fibril depends upon the physicochemical nature of stress. Our results present a physical basis of the effect of solvation conditions on inter- and intramolecular assembly formation of TDP-43 and reconcile why the nature and the internal structure of the aggregated form have been found to be different when extracted from the brain of different ALS patients.
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Affiliation(s)
- Abhilasha A Doke
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Santosh Kumar Jha
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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10
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Mori W, Kawakami R, Niko Y, Haruta T, Imamura T, Shiraki K, Zako T. Differences in interaction lead to the formation of different types of insulin amyloid. Sci Rep 2022; 12:8556. [PMID: 35595809 PMCID: PMC9123177 DOI: 10.1038/s41598-022-12212-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 05/04/2022] [Indexed: 11/25/2022] Open
Abstract
Insulin balls, localized insulin amyloids formed at the site of repeated insulin injections in patients with diabetes, cause poor glycemic control and cytotoxicity. Our previous study has shown that insulin forms two types of amyloids; toxic amyloid formed from the intact insulin ((i)-amyloid) and less-toxic amyloid formed in the presence of the reducing reagent TCEP ((r)-amyloid), suggesting insulin amyloid polymorphism. However, the differences in the formation mechanism and cytotoxicity expression are still unclear. Herein, we demonstrate that the liquid droplets, which are stabilized by electrostatic interactions, appear only in the process of toxic (i)-amyloid formation, but not in the less-toxic (r)-amyloid formation process. The effect of various additives such as arginine, 1,6-hexanediol, and salts on amyloid formation was also examined to investigate interactions that are important for amyloid formation. Our results indicate that the maturation processes of these two amyloids were significantly different, whereas the nucleation by hydrophobic interactions was similar. These results also suggest the difference in the formation mechanism of two different insulin amyloids is attributed to the difference in the intermolecular interactions and could be correlated with the cytotoxicity.
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Affiliation(s)
- Wakako Mori
- Department of Chemistry and Biology, Graduate School of Science and Engineering, Ehime University, Ehime, Japan
| | - Ryosuke Kawakami
- Department of Molecular Medicine for Pathogenesis, Graduate School of Medicine, Ehime University, Ehime, Japan
| | - Yosuke Niko
- Research and Education Faculty, Multidisciplinary Science Cluster, Interdisciplinary Science Unit, Kochi University, Kochi, Japan
| | | | - Takeshi Imamura
- Department of Molecular Medicine for Pathogenesis, Graduate School of Medicine, Ehime University, Ehime, Japan
| | - Kentaro Shiraki
- Faculty of Pure and Applied Sciences, University of Tsukuba, Ibaraki, Japan
| | - Tamotsu Zako
- Department of Chemistry and Biology, Graduate School of Science and Engineering, Ehime University, Ehime, Japan.
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11
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Ho WL, Huang JR. The return of the rings: Evolutionary convergence of aromatic residues in the intrinsically disordered regions of RNA-binding proteins for liquid-liquid phase separation. Protein Sci 2022; 31:e4317. [PMID: 35481633 PMCID: PMC9045073 DOI: 10.1002/pro.4317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 04/06/2022] [Indexed: 11/12/2022]
Abstract
Aromatic residues appeared relatively late in the evolution of protein sequences to stabilize the globular proteins' folding core and are less in the intrinsically disordered regions (IDRs). Recent advances in protein liquid-liquid phase separation (LLPS) studies have also shown that aromatic residues in IDRs often act as "stickers" to promote multivalent interactions in forming higher-order oligomers. To study how general these structure-promoting residues are in IDRs, we compared levels of sequence disorder in RNA binding proteins (RBPs), which are often found to undergo LLPS, and the human proteome. We found that aromatic residues appear more frequently than expected in the IDRs of RBPs and, through multiple sequence alignment analysis, those aromatic residues are often conserved among chordates. Using TDP-43, FUS, and some other well-studied LLPS proteins as examples, the conserved aromatic residues are important to their LLPS-related functions. These analyses suggest that aromatic residues may have contributed twice to evolution: stabilizing structured proteins and assembling biomolecular condensates.
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Affiliation(s)
- Wen-Lin Ho
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Jie-Rong Huang
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, Taiwan.,Institute of Biomedical Informatics, National Yang Ming Chiao Tung University, Taipei, Taiwan.,Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
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12
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Arseni D, Hasegawa M, Murzin AG, Kametani F, Arai M, Yoshida M, Ryskeldi-Falcon B. Structure of pathological TDP-43 filaments from ALS with FTLD. Nature 2022; 601:139-143. [PMID: 34880495 PMCID: PMC7612255 DOI: 10.1038/s41586-021-04199-3] [Citation(s) in RCA: 116] [Impact Index Per Article: 58.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 11/02/2021] [Indexed: 01/25/2023]
Abstract
The abnormal aggregation of TAR DNA-binding protein 43 kDa (TDP-43) in neurons and glia is the defining pathological hallmark of the neurodegenerative disease amyotrophic lateral sclerosis (ALS) and multiple forms of frontotemporal lobar degeneration (FTLD)1,2. It is also common in other diseases, including Alzheimer's and Parkinson's. No disease-modifying therapies exist for these conditions and early diagnosis is not possible. The structures of pathological TDP-43 aggregates are unknown. Here we used cryo-electron microscopy to determine the structures of aggregated TDP-43 in the frontal and motor cortices of an individual who had ALS with FTLD and from the frontal cortex of a second individual with the same diagnosis. An identical amyloid-like filament structure comprising a single protofilament was found in both brain regions and individuals. The ordered filament core spans residues 282-360 in the TDP-43 low-complexity domain and adopts a previously undescribed double-spiral-shaped fold, which shows no similarity to those of TDP-43 filaments formed in vitro3,4. An abundance of glycine and neutral polar residues facilitates numerous turns and restricts β-strand length, which results in an absence of β-sheet stacking that is associated with cross-β amyloid structure. An uneven distribution of residues gives rise to structurally and chemically distinct surfaces that face external densities and suggest possible ligand-binding sites. This work enhances our understanding of the molecular pathogenesis of ALS and FTLD and informs the development of diagnostic and therapeutic agents that target aggregated TDP-43.
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Affiliation(s)
- Diana Arseni
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Masato Hasegawa
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | | | - Fuyuki Kametani
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Makoto Arai
- Department of Psychiatry and Behavioural Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Mari Yoshida
- Institute for Medical Science of Aging, Aichi Medical University, Aichi, Japan
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13
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Esposto JC, Martic S. Phosphorylated TAR DNA-Binding Protein-43: Aggregation and Antibody-Based Inhibition. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166234. [PMID: 34339840 DOI: 10.1016/j.bbadis.2021.166234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/21/2021] [Accepted: 07/27/2021] [Indexed: 12/28/2022]
Abstract
TAR DNA-binding protein-43 (TDP-43) pathology, including fibrillar aggregates and mutations, develops in amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD) and limbic-predominant age-related TDP-43 encephalopathy (LATE). Hyperphosphorylation and aggregation of TDP-43 contribute to pathology and are viable therapeutic targets for ALS. In vivo inhibition of TDP-43 aggregation was evaluated using anti-TDP-43 antibodies with promising outcomes. However, the exact mechanism of antibody-based inhibition targeting TDP-43 is not well understood but may lead to the identification of viable immunotherapies. Herein, the mechanism of in vitro aggregation of phosphorylated TDP-43 was explored, and the anti-TDP-43 antibodies tested for their inhibitor efficacies. Specifically, the aggregation of phosphorylated full-length TDP-43 protein (pS410) was monitored by transmission electron microscopy (TEM), turbidity absorbance, and thioflavin (ThT). The protein aggregates were insoluble, ThT-positive and characterized with heterogeneous morphologies (fibers, amorphous structures). Antibodies specific to epitopes 178-393 and 256-269, within the RRM2-CTD domain, reduced the formation of β-sheets and insoluble aggregates, at low antibody loading (antibody: protein ratio = 1 ug/mL: 45 ug/mL). Inhibition outcomes were highly dependent on the type and loading of antibodies, indicating dual functionality of such inhibitors, as aggregation inhibitors or aggregation promoters. Anti-SOD1 and anti-tau antibodies were not effective inhibitors against TDP-43 aggregation, indicating selective inhibition.
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Affiliation(s)
- Josephine C Esposto
- Environmental and Life Sciences, Trent University, Peterborough, Ontario, Canada K9L 0G2.
| | - Sanela Martic
- Department of Forensic Science, Trent University, Peterborough, Ontario, Canada K9L 0G2.
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14
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Patni D, Jha SK. Protonation-Deprotonation Switch Controls the Amyloid-like Misfolding of Nucleic-Acid-Binding Domains of TDP-43. J Phys Chem B 2021; 125:8383-8394. [PMID: 34318672 DOI: 10.1021/acs.jpcb.1c03262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Nutrient starvation stress acidifies the cytosol and leads to the formation of large protein assemblies and misfolded aggregates. However, how starvation stress is sensed at the molecular level and leads to protein misfolding is poorly understood. TDP-43 is a vital protein, which, under stress-like conditions, associates with stress granule proteins via its functional nucleic-acid-binding domains (TDP-43tRRM) and misfolds to form aberrant aggregates. Here, we show that the monomeric N form of TDP-43tRRM forms a misfolded amyloid-like protein assembly, β form, in a pH-dependent manner and identified the critical protein side-chain residue whose protonation triggers its misfolding. We systematically mutated the three buried ionizable residues, D105, H166, and H256, to neutral amino acids to block the pH-dependent protonation-deprotonation titration of their side chain and studied their effect on the N-to-β transition. We observed that D105A and H256Q resembled TDP-43tRRM in their pH-dependent misfolding behavior. However, H166Q retains the N-like secondary structure under low-pH conditions and does not show pH-dependent misfolding to the β form. These results indicate that H166 is the critical side-chain residue whose protonation triggers the misfolding of TDP-43tRRM and shed light on how stress-induced misfolding of proteins during neurodegeneration could begin from site-specific triggers.
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Affiliation(s)
- Divya Patni
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Santosh Kumar Jha
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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15
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Ren Y, Li S, Chen S, Sun X, Yang F, Wang H, Li M, Cui F, Huang X. TDP-43 and Phosphorylated TDP-43 Levels in Paired Plasma and CSF Samples in Amyotrophic Lateral Sclerosis. Front Neurol 2021; 12:663637. [PMID: 34194383 PMCID: PMC8236522 DOI: 10.3389/fneur.2021.663637] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 05/19/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: The aim of this study was to measure both plasma and cerebrospinal fluid (CSF) TAR DNA-binding protein 43 (TDP-43) and phosphorylated TDP-43 (pTDP-43) levels in sporadic amyotrophic lateral sclerosis (sALS) patients, and to compare them with that of healthy controls. The correlation between plasma or CSF TDP-43/pTDP-43 and clinical indicators of ALS patients was assessed. Methods: Paired plasma and CSF TDP-43/pTDP-43 levels in 69 ALS patients and 59 healthy controls were measured by sandwich ELISA. Time to generalization (TTG), an indicator suggested that the time of symptoms spreading from spinal or bulbar localization to both, was evaluated in all patients screened for mutations in genes associated with ALS. Results: Both of the plasma TDP-43 and pTDP-43 levels were significantly higher in ALS patients than HCs (P < 0.001). The pTDP-43/TDP-43 ratios in plasma were significantly higher in HCs than ALS patients (P < 0.001). The area under the curve (AUC) value was 0.924 for plasma TDP-43 level, with a 91.3% sensitivity and 91.5% specificity. Moreover, the correlation between plasma and CSF TDP-43 was observed in each ALS patient (r = 0.195, P = 0.027). A correlation between CSF pTDP-43 levels and the ALSFRS-R (r = -0.245; P = 0.042) was established. A correlation was observed between plasma TDP-43 levels and TTG in ALS patients, which indicated that high levels of plasma TDP-43 correlated with prolonged TTG (r = 0.415; P = 0.004). Conclusion: The plasma TDP-43 and pTDP-43 levels might play an important role in diagnosis in the future study of ALS. The plasma TDP-43 might differentiate ALS and HC groups based on high sensitivity and specificity, and as an indicator of progression of disease.
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Affiliation(s)
- Yuting Ren
- Department of Neurology, First Medical Center, Chinese PLA General Hospital, Beijing, China.,Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Siyuan Li
- Department of Neurology, First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Siyu Chen
- Department of Geriatric Neurology, Second Medical Center and National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, Beijing, China
| | - Xiaosun Sun
- Department of Neurology, First Medical Center, Chinese PLA General Hospital, Beijing, China.,Department of Neurology, Tianjin Third Central Hospital, Tianjin, China
| | - Fei Yang
- Department of Neurology, First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Hongfen Wang
- Department of Neurology, First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Mao Li
- Department of Neurology, First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Fang Cui
- Department of Neurology, First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Xusheng Huang
- Department of Neurology, First Medical Center, Chinese PLA General Hospital, Beijing, China
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16
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Capitini C, Fani G, Vivoli Vega M, Penco A, Canale C, Cabrita LD, Calamai M, Christodoulou J, Relini A, Chiti F. Full-length TDP-43 and its C-terminal domain form filaments in vitro having non-amyloid properties. Amyloid 2021; 28:56-65. [PMID: 33026249 PMCID: PMC7613275 DOI: 10.1080/13506129.2020.1826425] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Accumulation of ubiquitin-positive, tau- and α-synuclein-negative intracellular inclusions of TDP-43 in the central nervous system represents the major hallmark correlated to amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U). Such inclusions have variably been described as amorphous aggregates or more structured deposits having amyloid properties. Here we have purified full-length TDP-43 (FL TDP-43) and its C-terminal domain (Ct TDP-43) to investigate the morphological, structural and tinctorial features of aggregates formed in vitro by them at pH 7.4 and 37 °C. AFM images indicate that both protein variants show a tendency to form filaments. Moreover, we show that both FL TDP-43 and Ct TDP-43 filaments possess a largely disordered secondary structure, as ascertained by far-UV circular dichroism and Fourier transform infra-red spectroscopy, do not bind Congo red and induce a very weak increase of thioflavin T fluorescence, indicating the absence of a clear amyloid-like signature.
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Affiliation(s)
- Claudia Capitini
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy.,European Laboratory for Non-linear Spectroscopy, Sesto Fiorentino, Italy
| | - Giulia Fani
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Mirella Vivoli Vega
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Amanda Penco
- Department of Physics, University of Genoa, Genoa, Italy
| | - Claudio Canale
- Department of Physics, University of Genoa, Genoa, Italy
| | - Lisa D Cabrita
- Institute of Structural and Molecular Biology, UCL and Birkbeck College London, London, UK
| | - Martino Calamai
- European Laboratory for Non-linear Spectroscopy, Sesto Fiorentino, Italy.,National Institute of Optics, National Research Council, Sesto Fiorentino, Italy
| | - John Christodoulou
- Institute of Structural and Molecular Biology, UCL and Birkbeck College London, London, UK
| | | | - Fabrizio Chiti
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
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17
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Babinchak WM, Surewicz WK. Liquid-Liquid Phase Separation and Its Mechanistic Role in Pathological Protein Aggregation. J Mol Biol 2020; 432:1910-1925. [PMID: 32169484 DOI: 10.1016/j.jmb.2020.03.004] [Citation(s) in RCA: 133] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 12/14/2022]
Abstract
Liquid-liquid phase separation (LLPS) of proteins underlies the formation of membrane-less organelles. While it has been recognized for some time that these organelles are of key importance for normal cellular functions, a growing number of recent observations indicate that LLPS may also play a role in disease. In particular, numerous proteins that form toxic aggregates in neurodegenerative diseases, such as amyotrophic lateral sclerosis, frontotemporal lobar degeneration, and Alzheimer's disease, were found to be highly prone to phase separation, suggesting that there might be a strong link between LLPS and the pathogenic process in these disorders. This review aims to assess the molecular basis of this link through exploration of the intermolecular interactions that underlie LLPS and aggregation and the underlying mechanisms facilitating maturation of liquid droplets into more stable assemblies, including so-called labile fibrils, hydrogels, and pathological amyloids. Recent insights into the structural basis of labile fibrils and potential mechanisms by which these relatively unstable structures could transition into more stable pathogenic amyloids are also discussed. Finally, this review explores how the environment of liquid droplets could modulate protein aggregation by altering kinetics of protein self-association, affecting folding of protein monomers, or changing aggregation pathways.
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Affiliation(s)
- W Michael Babinchak
- Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Witold K Surewicz
- Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA.
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18
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Zhuo XF, Wang J, Zhang J, Jiang LL, Hu HY, Lu JX. Solid-State NMR Reveals the Structural Transformation of the TDP-43 Amyloidogenic Region upon Fibrillation. J Am Chem Soc 2020; 142:3412-3421. [PMID: 32003979 DOI: 10.1021/jacs.9b10736] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
TDP-43 is a primary pathological hallmark protein of amyotrophic lateral sclerosis and frontotemporal lobar degeneration, which may exist in the form of amyloid inclusions in the cells of patients. In addition to serving as a biomarker for these diseases, TDP-43 can also directly trigger neurodegeneration. We previously determined the amyloidogenic core region of TDP-43 (residues 311-360) and showed by solution NMR that this region includes two α-helices [(321-330) and (335-343)] in solution. We suggested that the helix-to-sheet structural transformation initiates TDP-43 aggregation. In the present study, X-ray diffraction shows that TDP-43 (311-360) aggregates adopt a cross-β structure. Thioredoxin (Trx)-fused TDP-43 (311-360) can undergo liquid-liquid phase separation (LLPS) before fibrillation, suggesting that phase separation is an intermediate step before amyloid formation. Solid-state NMR (SSNMR), carried out to elucidate the structural changes of TDP-43 (311-360) at the atomic level, indicates five β-strands of the amyloids formed, with the major two β-strands contributed by the first helical region in the solution structure. The NMR evidence is also in support of the fibril having a parallel in-register conformation, implying a mechanism in which the helix-helix interactions in LLPS are converted into β-strand parallel lateral association upon fibrillation. Our studies have assigned many key interresidue interactions that contribute to the stability of the fibril, including F316 with I318 and Q327 and W334 with A325, A326, A329, and S332. SSNMR with 1H detection reveals a unique close interaction between the indole Nε1-Hε1 of W334 and the side-chain carbonyl of Q343. This interaction could be a very important factor in initiating TDP-43 (311-360) folding/misfolding in LLPS.
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Affiliation(s)
- Xiao-Feng Zhuo
- School of Life Science and Technology , ShanghaiTech University , Shanghai 201210 , People's Republic of China.,State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science , Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences , Shanghai 200031 , People's Republic of China.,University of Chinese Academy of Sciences , Beijing 100049 , People's Republic of China
| | - Jian Wang
- School of Life Science and Technology , ShanghaiTech University , Shanghai 201210 , People's Republic of China
| | - Jing Zhang
- School of Life Science and Technology , ShanghaiTech University , Shanghai 201210 , People's Republic of China.,State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science , Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences , Shanghai 200031 , People's Republic of China.,University of Chinese Academy of Sciences , Beijing 100049 , People's Republic of China
| | - Lei-Lei Jiang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science , Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences , Shanghai 200031 , People's Republic of China
| | - Hong-Yu Hu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science , Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences , Shanghai 200031 , People's Republic of China
| | - Jun-Xia Lu
- School of Life Science and Technology , ShanghaiTech University , Shanghai 201210 , People's Republic of China
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19
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François-Moutal L, Perez-Miller S, Scott DD, Miranda VG, Mollasalehi N, Khanna M. Structural Insights Into TDP-43 and Effects of Post-translational Modifications. Front Mol Neurosci 2019; 12:301. [PMID: 31920533 PMCID: PMC6934062 DOI: 10.3389/fnmol.2019.00301] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 11/25/2019] [Indexed: 12/12/2022] Open
Abstract
Transactive response DNA binding protein (TDP-43) is a key player in neurodegenerative diseases. In this review, we have gathered and presented structural information on the different regions of TDP-43 with high resolution structures available. A thorough understanding of TDP-43 structure, effect of modifications, aggregation and sites of localization is necessary as we develop therapeutic strategies targeting TDP-43 for neurodegenerative diseases. We discuss how different domains as well as post-translational modification may influence TDP-43 overall structure, aggregation and droplet formation. The primary aim of the review is to utilize structural insights as we develop an understanding of the deleterious behavior of TDP-43 and highlight locations of established and proposed post-translation modifications. TDP-43 structure and effect on localization is paralleled by many RNA-binding proteins and this review serves as an example of how structure may be modulated by numerous compounding elements.
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Affiliation(s)
- Liberty François-Moutal
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
| | - Samantha Perez-Miller
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
| | - David D Scott
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
| | - Victor G Miranda
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
| | - Niloufar Mollasalehi
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States.,Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States
| | - May Khanna
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
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20
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Driving Forces of Liquid-Liquid Phase Separation in Biological Systems. Biomolecules 2019; 9:biom9090473. [PMID: 31510097 PMCID: PMC6770153 DOI: 10.3390/biom9090473] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 09/02/2019] [Indexed: 12/03/2022] Open
Abstract
Analysis of liquid–liquid phase separation in biological systems shows that this process is similar to the phase separation observed in aqueous two-phase systems formed by nonionic polymers, proteins, and polysaccharides. The emergence of interfacial tension is a necessary condition of phase separation. The situation in this regard is similar to that of phase separation in mixtures of partially miscible solvents. It is suggested that the evaluation of the effects of biological macromolecules on the solvent properties of aqueous media and the measurement of the interfacial tension as a function of these solvent properties may be more productive for gaining insights into the mechanism of liquid–liquid phase separation than the study of structural details of proteins and RNAs engaged in the process.
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21
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Gao J, Wang L, Yan T, Perry G, Wang X. TDP-43 proteinopathy and mitochondrial abnormalities in neurodegeneration. Mol Cell Neurosci 2019; 100:103396. [PMID: 31445085 DOI: 10.1016/j.mcn.2019.103396] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 07/03/2019] [Accepted: 08/17/2019] [Indexed: 12/12/2022] Open
Abstract
Genetic mutations in TAR DNA-binding protein 43 (TDP-43) cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Importantly, TDP-43 proteinopathy, characterized by aberrant phosphorylation, ubiquitination, cleavage or nuclear depletion of TDP-43 in neurons and glial cells, is a common prominent pathological feature of various major neurodegenerative diseases including ALS, FTD, and Alzheimer's disease (AD). Although the pathomechanisms underlying TDP-43 proteinopathy remain elusive, pathologically relevant TDP-43 has been repeatedly shown to be present in either the inside or outside of mitochondria, and functionally involved in the regulation of mitochondrial morphology, trafficking, and function, suggesting mitochondria as likely targets of TDP-43 proteinopathy. In this review, we first describe the current knowledge of the association of TDP-43 with mitochondria. We then review in detail multiple mitochondrial pathways perturbed by pathological TDP-43, including mitochondrial fission and fusion dynamics, mitochondrial trafficking, bioenergetics, and mitochondrial quality control. Lastly, we briefly discuss how the study of TDP-43 proteinopathy and mitochondrial abnormalities may provide new avenues for neurodegeneration therapeutics.
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Affiliation(s)
- Ju Gao
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Luwen Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Tingxiang Yan
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - George Perry
- College of Sciences, University of Texas at San Antonio, San Antonio, TX, USA
| | - Xinglong Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA.
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