1
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Agha MM, Uversky VN. Morphological features and types of aggregated structures. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2024; 206:85-109. [PMID: 38811090 DOI: 10.1016/bs.pmbts.2024.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
In vivo, protein aggregation arises due to incorrect folding or misfolding. The aggregation of proteins into amyloid fibrils is the characteristic feature of various misfolding diseases known as amyloidosis, such as Alzheimer's and Parkinson's disease. The heterogeneous nature of these fibrils restricts the extent to which their structure may be characterized. Advancements in techniques, such as X-ray diffraction, cryo-electron microscopy, and solid-state NMR have yielded intricate insights into structures of different amyloid fibrils. These studies have unveiled a diverse range of polymorphic structures that typically conform to the cross-β amyloid pattern. This chapter provides a concise overview of the information acquired in the field of protein aggregation, with particular focus on amyloids.
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Affiliation(s)
- Mansoureh Mirza Agha
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Vladimir N Uversky
- Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Institute for Biological Instrumentation, Pushchino, Russia; Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States.
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2
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Zhou W, Zhou R. Vision SLAM algorithm for wheeled robots integrating multiple sensors. PLoS One 2024; 19:e0301189. [PMID: 38547130 PMCID: PMC10977683 DOI: 10.1371/journal.pone.0301189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 03/12/2024] [Indexed: 04/02/2024] Open
Abstract
Wheeled robots play a crucial role in driving the autonomy and intelligence of robotics. However, they often encounter challenges such as tracking loss and poor real-time performance in low-texture environments. In response to these issues, this research proposes a real-time localization and mapping algorithm based on the fusion of multiple features, utilizing point, line, surface, and matrix decomposition characteristics. Building upon this foundation, the algorithm integrates multiple sensors to design a vision-based real-time localization and mapping algorithm for wheeled robots. The study concludes with experimental validation on a two-wheeled robot platform. The results indicated that the multi-feature fusion algorithm achieved the highest average accuracy in both conventional indoor datasets (84.57%) and sparse-feature indoor datasets (82.37%). In indoor scenarios, the vision-based algorithm integrating multiple sensors achieved an average accuracy of 85.4% with a processing time of 64.4 ms. In outdoor scenarios, the proposed algorithm exhibited a 14.51% accuracy improvement over a vision-based algorithm without closed-loop detection. In summary, the proposed method demonstrated outstanding accuracy and real-time performance, exhibiting favorable application effects across various practical scenarios.
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Affiliation(s)
- Weihua Zhou
- School of Computer and Information Technology (School of Big Data), Shanxi University, Taiyuan, 030002, China
| | - Rougang Zhou
- School of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou, 310018, China
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3
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Bobylev AG, Yakupova EI, Bobyleva LG, Molochkov NV, Timchenko AA, Timchenko MA, Kihara H, Nikulin AD, Gabdulkhakov AG, Melnik TN, Penkov NV, Lobanov MY, Kazakov AS, Kellermayer M, Mártonfalvi Z, Galzitskaya OV, Vikhlyantsev IM. Nonspecific Amyloid Aggregation of Chicken Smooth-Muscle Titin: In Vitro Investigations. Int J Mol Sci 2023; 24:ijms24021056. [PMID: 36674570 PMCID: PMC9861715 DOI: 10.3390/ijms24021056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/29/2022] [Accepted: 12/29/2022] [Indexed: 01/06/2023] Open
Abstract
A giant multidomain protein of striated and smooth vertebrate muscles, titin, consists of tandems of immunoglobulin (Ig)- and fibronectin type III (FnIII)-like domains representing β-sandwiches, as well as of disordered segments. Chicken smooth muscles express several titin isoforms of ~500-1500 kDa. Using various structural-analysis methods, we investigated in vitro nonspecific amyloid aggregation of the high-molecular-weight isoform of chicken smooth-muscle titin (SMTHMW, ~1500 kDa). As confirmed by X-ray diffraction analysis, under near-physiological conditions, the protein formed amorphous amyloid aggregates with a quaternary cross-β structure within a relatively short time (~60 min). As shown by circular dichroism and Fourier-transform infrared spectroscopy, the quaternary cross-β structure-unlike other amyloidogenic proteins-formed without changes in the SMTHMW secondary structure. SMTHMW aggregates partially disaggregated upon increasing the ionic strength above the physiological level. Based on the data obtained, it is not the complete protein but its particular domains/segments that are likely involved in the formation of intermolecular interactions during SMTHMW amyloid aggregation. The discovered properties of titin position this protein as an object of interest for studying amyloid aggregation in vitro and expanding our views of the fundamentals of amyloidogenesis.
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Affiliation(s)
- Alexander G. Bobylev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
- Correspondence: (A.G.B.); (I.M.V.)
| | - Elmira I. Yakupova
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow Region, Russia
| | - Liya G. Bobyleva
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
| | - Nikolay V. Molochkov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
| | - Alexander A. Timchenko
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
| | - Maria A. Timchenko
- Institute for Biological Instrumentation, Federal Research Center, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
| | - Hiroshi Kihara
- Department of Early Childhood Education, Himeji-Hinomoto College, 890 Koro, Kodera-cho, Himeji 679-2151, Japan
| | - Alexey D. Nikulin
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
| | - Azat G. Gabdulkhakov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
| | - Tatiana N. Melnik
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
| | - Nikita V. Penkov
- Institute of Cell Biophysics, FRC PSCBR, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
| | - Michail Y. Lobanov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
| | - Alexey S. Kazakov
- Institute for Biological Instrumentation, Federal Research Center, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
| | - Miklós Kellermayer
- Department of Biophysics and Radiation Biology, Semmelweis University, 1085 Budapest, Hungary
| | - Zsolt Mártonfalvi
- Department of Biophysics and Radiation Biology, Semmelweis University, 1085 Budapest, Hungary
| | - Oxana V. Galzitskaya
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
| | - Ivan M. Vikhlyantsev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia
- Correspondence: (A.G.B.); (I.M.V.)
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4
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Tahirbegi B, Magness AJ, Piersimoni ME, Teng X, Hooper J, Guo Y, Knöpfel T, Willison KR, Klug DR, Ying L. Toward high-throughput oligomer detection and classification for early-stage aggregation of amyloidogenic protein. Front Chem 2022; 10:967882. [PMID: 36110142 PMCID: PMC9468268 DOI: 10.3389/fchem.2022.967882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 07/28/2022] [Indexed: 12/01/2022] Open
Abstract
Aggregation kinetics of proteins and peptides have been studied extensively due to their significance in many human diseases, including neurodegenerative disorders, and the roles they play in some key physiological processes. However, most of these studies have been performed as bulk measurements using Thioflavin T or other fluorescence turn-on reagents as indicators of fibrillization. Such techniques are highly successful in making inferences about the nucleation and growth mechanism of fibrils, yet cannot directly measure assembly reactions at low protein concentrations which is the case for amyloid-β (Aβ) peptide under physiological conditions. In particular, the evolution from monomer to low-order oligomer in early stages of aggregation cannot be detected. Single-molecule methods allow direct access to such fundamental information. We developed a high-throughput protocol for single-molecule photobleaching experiments using an automated fluorescence microscope. Stepwise photobleaching analysis of the time profiles of individual foci allowed us to determine stoichiometry of protein oligomers and probe protein aggregation kinetics. Furthermore, we investigated the potential application of supervised machine learning with support vector machines (SVMs) as well as multilayer perceptron (MLP) artificial neural networks to classify bleaching traces into stoichiometric categories based on an ensemble of measurable quantities derivable from individual traces. Both SVM and MLP models achieved a comparable accuracy of more than 80% against simulated traces up to 19-mer, although MLP offered considerable speed advantages, thus making it suitable for application to high-throughput experimental data. We used our high-throughput method to study the aggregation of Aβ40 in the presence of metal ions and the aggregation of α-synuclein in the presence of gold nanoparticles.
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Affiliation(s)
- Bogachan Tahirbegi
- Department of Chemistry, Imperial College London, London, United Kingdom
| | - Alastair J. Magness
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | | | - Xiangyu Teng
- Department of Chemistry, Imperial College London, London, United Kingdom
| | - James Hooper
- School of Food Science and Nutrition and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Yuan Guo
- School of Food Science and Nutrition and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Thomas Knöpfel
- Department of Brain Sciences, Imperial College London, London, United Kingdom
| | - Keith R. Willison
- Department of Chemistry, Imperial College London, London, United Kingdom
| | - David R. Klug
- Department of Chemistry, Imperial College London, London, United Kingdom
| | - Liming Ying
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
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5
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Sirati N, Popova B, Molenaar MR, Verhoek IC, Braus GH, Kaloyanova DV, Helms JB. Dynamic and Reversible Aggregation of the Human CAP Superfamily Member GAPR-1 in Protein Inclusions in Saccharomyces cerevisiae. J Mol Biol 2021; 433:167162. [PMID: 34298062 DOI: 10.1016/j.jmb.2021.167162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 12/14/2022]
Abstract
Many proteins that can assemble into higher order structures termed amyloids can also concentrate into cytoplasmic inclusions via liquid-liquid phase separation. Here, we study the assembly of human Golgi-Associated plant Pathogenesis Related protein 1 (GAPR-1), an amyloidogenic protein of the Cysteine-rich secretory proteins, Antigen 5, and Pathogenesis-related 1 proteins (CAP) protein superfamily, into cytosolic inclusions in Saccharomyces cerevisiae. Overexpression of GAPR-1-GFP results in the formation GAPR-1 oligomers and fluorescent inclusions in yeast cytosol. These cytosolic inclusions are dynamic and reversible organelles that gradually increase during time of overexpression and decrease after promoter shut-off. Inclusion formation is, however, a regulated process that is influenced by factors other than protein expression levels. We identified N-myristoylation of GAPR-1 as an important determinant at early stages of inclusion formation. In addition, mutations in the conserved metal-binding site (His54 and His103) enhanced inclusion formation, suggesting that these residues prevent uncontrolled protein sequestration. In agreement with this, we find that addition of Zn2+ metal ions enhances inclusion formation. Furthermore, Zn2+ reduces GAPR-1 protein degradation, which indicates stabilization of GAPR-1 in inclusions. We propose that the properties underlying both the amyloidogenic properties and the reversible sequestration of GAPR-1 into inclusions play a role in the biological function of GAPR-1 and other CAP family members.
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Affiliation(s)
- Nafiseh Sirati
- Division of Cell Biology, Metabolism and Cancer, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
| | - Blagovesta Popova
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Institute for Microbiology and Genetics, Universität Göttingen, Göttingen, Germany
| | - Martijn R Molenaar
- Division of Cell Biology, Metabolism and Cancer, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Iris C Verhoek
- Division of Cell Biology, Metabolism and Cancer, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Gerhard H Braus
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Institute for Microbiology and Genetics, Universität Göttingen, Göttingen, Germany
| | - Dora V Kaloyanova
- Division of Cell Biology, Metabolism and Cancer, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - J Bernd Helms
- Division of Cell Biology, Metabolism and Cancer, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
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6
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Lutter L, Aubrey LD, Xue WF. On the Structural Diversity and Individuality of Polymorphic Amyloid Protein Assemblies. J Mol Biol 2021; 433:167124. [PMID: 34224749 DOI: 10.1016/j.jmb.2021.167124] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/20/2021] [Accepted: 06/26/2021] [Indexed: 12/24/2022]
Abstract
The prediction of highly ordered three-dimensional structures of amyloid protein fibrils from the amino acid sequences of their monomeric self-assembly precursors constitutes a challenging and unresolved aspect of the classical protein folding problem. Because of the polymorphic nature of amyloid assembly whereby polypeptide chains of identical amino acid sequences under identical conditions are capable of self-assembly into a spectrum of different fibril structures, the prediction of amyloid structures from an amino acid sequence requires a detailed and holistic understanding of its assembly free energy landscape. The full extent of the structure space accessible to the cross-β molecular architecture of amyloid must also be resolved. Here, we review the current understanding of the diversity and the individuality of amyloid structures, and how the polymorphic landscape of amyloid links to biology and disease phenotypes. We present a comprehensive review of structural models of amyloid fibrils derived by cryo-EM, ssNMR and AFM to date, and discuss the challenges ahead for resolving the structural basis and the biological consequences of polymorphic amyloid assemblies.
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Affiliation(s)
- Liisa Lutter
- School of Biosciences, Division of Natural Sciences, University of Kent, CT2 7NJ Canterbury, UK
| | - Liam D Aubrey
- School of Biosciences, Division of Natural Sciences, University of Kent, CT2 7NJ Canterbury, UK
| | - Wei-Feng Xue
- School of Biosciences, Division of Natural Sciences, University of Kent, CT2 7NJ Canterbury, UK.
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7
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Kumar V, Sinha N, Thakur AK. Necessity of regulatory guidelines for the development of amyloid based biomaterials. Biomater Sci 2021; 9:4410-4422. [PMID: 34018497 DOI: 10.1039/d1bm00059d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Amyloid diseases are caused due to protein homeostasis failure where incorrectly folded proteins/peptides form cross-β-sheet rich amyloid fibrillar structures. Besides proteins/peptides, small metabolite assemblies also exhibit amyloid-like features. These structures are linked to several human and animal diseases. In addition, non-toxic amyloids with diverse physiological roles are characterized as a new functional class. This finding, along with the unique properties of amyloid like stability and mechanical strength, led to a surge in the development of amyloid-based biomaterials. However, the usage of these materials by humans and animals may pose a health risk such as the development of amyloid diseases and toxicity. This is possible because amyloid-based biomaterials and their fragments may assist seeding and cross-seeding mechanisms of amyloid formation in the body. This review summarizes the potential uses of amyloids as biomaterials, the concerns regarding their usage, and a prescribed workflow to initiate a regulatory approach.
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Affiliation(s)
- Vijay Kumar
- Department of Molecular Microbiology and Biotechnology, Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Nabodita Sinha
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, UP-208016, India.
| | - Ashwani Kumar Thakur
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, UP-208016, India.
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8
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Yakupova EI, Bobyleva LG, Shumeyko SA, Vikhlyantsev IM, Bobylev AG. Amyloids: The History of Toxicity and Functionality. BIOLOGY 2021; 10:biology10050394. [PMID: 34062910 PMCID: PMC8147320 DOI: 10.3390/biology10050394] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/26/2021] [Accepted: 04/29/2021] [Indexed: 12/15/2022]
Abstract
Proteins can perform their specific function due to their molecular structure. Partial or complete unfolding of the polypeptide chain may lead to the misfolding and aggregation of proteins in turn, resulting in the formation of different structures such as amyloid aggregates. Amyloids are rigid protein aggregates with the cross-β structure, resistant to most solvents and proteases. Because of their resistance to proteolysis, amyloid aggregates formed in the organism accumulate in tissues, promoting the development of various diseases called amyloidosis, for instance Alzheimer's diseases (AD). According to the main hypothesis, it is considered that the cause of AD is the formation and accumulation of amyloid plaques of Aβ. That is why Aβ-amyloid is the most studied representative of amyloids. Therefore, in this review, special attention is paid to the history of Aβ-amyloid toxicity. We note the main problems with anti-amyloid therapy and write about new views on amyloids that can play positive roles in the different organisms including humans.
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Affiliation(s)
- Elmira I. Yakupova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, 142290 Moscow, Russia; (L.G.B.); (S.A.S.); (I.M.V.); (A.G.B.)
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
- Correspondence: ; Tel.: +7-(985)687-77-27
| | - Liya G. Bobyleva
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, 142290 Moscow, Russia; (L.G.B.); (S.A.S.); (I.M.V.); (A.G.B.)
| | - Sergey A. Shumeyko
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, 142290 Moscow, Russia; (L.G.B.); (S.A.S.); (I.M.V.); (A.G.B.)
| | - Ivan M. Vikhlyantsev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, 142290 Moscow, Russia; (L.G.B.); (S.A.S.); (I.M.V.); (A.G.B.)
| | - Alexander G. Bobylev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, 142290 Moscow, Russia; (L.G.B.); (S.A.S.); (I.M.V.); (A.G.B.)
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9
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Kumar A, Balbach J. Inactivation of parathyroid hormone: perspectives of drug discovery to combating hyperparathyroidism. Curr Mol Pharmacol 2021; 15:292-305. [PMID: 33573587 DOI: 10.2174/1874467214666210126112839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 11/22/2022]
Abstract
Hormonal coordination is tightly regulated within the human body and thus regulates human physiology. The parathyroid hormone (PTH), a member of the endocrine system, regulates the calcium and phosphate level within the human body. Under non-physiological conditions, PTH levels get upregulated (hyperparathyroidism) or downregulated (hypoparathyroidism) due to external or internal factors. In the case of hyperparathyroidism, elevated PTH stimulates cellular receptors present in the bones, kidneys, and intestines to increase the blood calcium level, leading to calcium deposition. This eventually causes various symptoms including kidney stones. Currently, there is no known medication that directly targets PTH in order to suppress its function. Therefore, it is of great interest to find novel small molecules or any other means that can modulate PTH function. The molecular signaling of PTH starts by binding of its N-terminus to the G-protein coupled PTH1/2 receptor. Therefore, any intervention that affects the N-terminus of PTH could be a lead candidate for treating hyperparathyroidism. As a proof-of-concept, there are various possibilities to inhibit molecular PTH function by (i) a small molecule, (ii) N-terminal PTH phosphorylation, (iii) fibril formation and (iv) residue-specific mutations. These modifications put PTH into an inactive state, which will be discussed in detail in this review article. We anticipate that exploring small molecules or other means that affect the N-terminus of PTH could be lead candidates in combating hyperparathyroidism.
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Affiliation(s)
- Amit Kumar
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College of Science, Technology and Medicine London, South Kensington, London SW7 2BU. United Kingdom
| | - Jochen Balbach
- Institute of Physics, Biophysics, Martin-Luther-University Halle- Wittenberg. Germany
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10
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Cawood EE, Karamanos TK, Wilson AJ, Radford SE. Visualizing and trapping transient oligomers in amyloid assembly pathways. Biophys Chem 2021; 268:106505. [PMID: 33220582 PMCID: PMC8188297 DOI: 10.1016/j.bpc.2020.106505] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 10/29/2020] [Accepted: 11/01/2020] [Indexed: 12/31/2022]
Abstract
Oligomers which form during amyloid fibril assembly are considered to be key contributors towards amyloid disease. However, understanding how such intermediates form, their structure, and mechanisms of toxicity presents significant challenges due to their transient and heterogeneous nature. Here, we discuss two different strategies for addressing these challenges: use of (1) methods capable of detecting lowly-populated species within complex mixtures, such as NMR, single particle methods (including fluorescence and force spectroscopy), and mass spectrometry; and (2) chemical and biological tools to bias the amyloid energy landscape towards specific oligomeric states. While the former methods are well suited to following the kinetics of amyloid assembly and obtaining low-resolution structural information, the latter are capable of producing oligomer samples for high-resolution structural studies and inferring structure-toxicity relationships. Together, these different approaches should enable a clearer picture to be gained of the nature and role of oligomeric intermediates in amyloid formation and disease.
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Affiliation(s)
- Emma E Cawood
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK
| | - Theodoros K Karamanos
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK; Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andrew J Wilson
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, LS2 9JT, UK.
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK.
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11
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Ulamec SM, Brockwell DJ, Radford SE. Looking Beyond the Core: The Role of Flanking Regions in the Aggregation of Amyloidogenic Peptides and Proteins. Front Neurosci 2020; 14:611285. [PMID: 33335475 PMCID: PMC7736610 DOI: 10.3389/fnins.2020.611285] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 11/02/2020] [Indexed: 12/14/2022] Open
Abstract
Amyloid proteins are involved in many neurodegenerative disorders such as Alzheimer’s disease [Tau, Amyloid β (Aβ)], Parkinson’s disease [alpha-synuclein (αSyn)], and amyotrophic lateral sclerosis (TDP-43). Driven by the early observation of the presence of ordered structure within amyloid fibrils and the potential to develop inhibitors of their formation, a major goal of the amyloid field has been to elucidate the structure of the amyloid fold at atomic resolution. This has now been achieved for a wide variety of sequences using solid-state NMR, microcrystallography, X-ray fiber diffraction and cryo-electron microscopy. These studies, together with in silico methods able to predict aggregation-prone regions (APRs) in protein sequences, have provided a wealth of information about the ordered fibril cores that comprise the amyloid fold. Structural and kinetic analyses have also shown that amyloidogenic proteins often contain less well-ordered sequences outside of the amyloid core (termed here as flanking regions) that modulate function, toxicity and/or aggregation rates. These flanking regions, which often form a dynamically disordered “fuzzy coat” around the fibril core, have been shown to play key parts in the physiological roles of functional amyloids, including the binding of RNA and in phase separation. They are also the mediators of chaperone binding and membrane binding/disruption in toxic amyloid assemblies. Here, we review the role of flanking regions in different proteins spanning both functional amyloid and amyloid in disease, in the context of their role in aggregation, toxicity and cellular (dys)function. Understanding the properties of these regions could provide new opportunities to target disease-related aggregation without disturbing critical biological functions.
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Affiliation(s)
- Sabine M Ulamec
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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12
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Sheng J, Olrichs NK, Gadella BM, Kaloyanova DV, Helms JB. Regulation of Functional Protein Aggregation by Multiple Factors: Implications for the Amyloidogenic Behavior of the CAP Superfamily Proteins. Int J Mol Sci 2020; 21:E6530. [PMID: 32906672 PMCID: PMC7554809 DOI: 10.3390/ijms21186530] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/01/2020] [Accepted: 09/03/2020] [Indexed: 12/13/2022] Open
Abstract
The idea that amyloid fibrils and other types of protein aggregates are toxic for cells has been challenged by the discovery of a variety of functional aggregates. However, an identification of crucial differences between pathological and functional aggregation remains to be explored. Functional protein aggregation is often reversible by nature in order to respond properly to changing physiological conditions of the cell. In addition, increasing evidence indicates that fast fibril growth is a feature of functional amyloids, providing protection against the long-term existence of potentially toxic oligomeric intermediates. It is becoming clear that functional protein aggregation is a complexly organized process that can be mediated by a multitude of biomolecular factors. In this overview, we discuss the roles of diverse biomolecules, such as lipids/membranes, glycosaminoglycans, nucleic acids and metal ions, in regulating functional protein aggregation. Our studies on the protein GAPR-1 revealed that several of these factors influence the amyloidogenic properties of this protein. These observations suggest that GAPR-1, as well as the cysteine-rich secretory proteins, antigen 5 and pathogenesis-related proteins group 1 (CAP) superfamily of proteins that it belongs to, require the assembly into an amyloid state to exert several of their functions. A better understanding of functional aggregate formation may also help in the prevention and treatment of amyloid-related diseases.
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Affiliation(s)
| | | | | | | | - J. Bernd Helms
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands; (J.S.); (N.K.O.); (B.M.G.); (D.V.K.)
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