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Langerscheidt F, Wied T, Al Kabbani MA, van Eimeren T, Wunderlich G, Zempel H. Genetic forms of tauopathies: inherited causes and implications of Alzheimer's disease-like TAU pathology in primary and secondary tauopathies. J Neurol 2024; 271:2992-3018. [PMID: 38554150 PMCID: PMC11136742 DOI: 10.1007/s00415-024-12314-3] [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: 01/25/2024] [Revised: 03/06/2024] [Accepted: 03/07/2024] [Indexed: 04/01/2024]
Abstract
Tauopathies are a heterogeneous group of neurologic diseases characterized by pathological axodendritic distribution, ectopic expression, and/or phosphorylation and aggregation of the microtubule-associated protein TAU, encoded by the gene MAPT. Neuronal dysfunction, dementia, and neurodegeneration are common features of these often detrimental diseases. A neurodegenerative disease is considered a primary tauopathy when MAPT mutations/haplotypes are its primary cause and/or TAU is the main pathological feature. In case TAU pathology is observed but superimposed by another pathological hallmark, the condition is classified as a secondary tauopathy. In some tauopathies (e.g. MAPT-associated frontotemporal dementia (FTD), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and Alzheimer's disease (AD)) TAU is recognized as a significant pathogenic driver of the disease. In many secondary tauopathies, including Parkinson's disease (PD) and Huntington's disease (HD), TAU is suggested to contribute to the development of dementia, but in others (e.g. Niemann-Pick disease (NPC)) TAU may only be a bystander. The genetic and pathological mechanisms underlying TAU pathology are often not fully understood. In this review, the genetic predispositions and variants associated with both primary and secondary tauopathies are examined in detail, assessing evidence for the role of TAU in these conditions. We highlight less common genetic forms of tauopathies to increase awareness for these disorders and the involvement of TAU in their pathology. This approach not only contributes to a deeper understanding of these conditions but may also lay the groundwork for potential TAU-based therapeutic interventions for various tauopathies.
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Affiliation(s)
- Felix Langerscheidt
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931, Cologne, Germany
| | - Tamara Wied
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931, Cologne, Germany
- Department of Natural Sciences, Bonn-Rhein-Sieg University of Applied Sciences, Von-Liebig-Str. 20, 53359, Rheinbach, Germany
| | - Mohamed Aghyad Al Kabbani
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931, Cologne, Germany
| | - Thilo van Eimeren
- Multimodal Neuroimaging Group, Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937, Cologne, Germany
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937, Cologne, Germany
| | - Gilbert Wunderlich
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937, Cologne, Germany
- Center for Rare Diseases, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany
| | - Hans Zempel
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany.
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931, Cologne, Germany.
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Ellis MJ, Lekka C, Holden KL, Tulmin H, Seedat F, O'Brien DP, Dhayal S, Zeissler ML, Knudsen JG, Kessler BM, Morgan NG, Todd JA, Richardson SJ, Stefana MI. Identification of high-performing antibodies for the reliable detection of Tau proteoforms by Western blotting and immunohistochemistry. Acta Neuropathol 2024; 147:87. [PMID: 38761203 PMCID: PMC11102361 DOI: 10.1007/s00401-024-02729-7] [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: 11/07/2023] [Revised: 04/03/2024] [Accepted: 04/03/2024] [Indexed: 05/20/2024]
Abstract
Antibodies are essential research tools whose performance directly impacts research conclusions and reproducibility. Owing to its central role in Alzheimer's disease and other dementias, hundreds of distinct antibody clones have been developed against the microtubule-associated protein Tau and its multiple proteoforms. Despite this breadth of offer, limited understanding of their performance and poor antibody selectivity have hindered research progress. Here, we validate a large panel of Tau antibodies by Western blot (79 reagents) and immunohistochemistry (35 reagents). We address the reagents' ability to detect the target proteoform, selectivity, the impact of protein phosphorylation on antibody binding and performance in human brain samples. While most antibodies detected Tau at high levels, many failed to detect it at lower, endogenous levels. By WB, non-selective binding to other proteins affected over half of the antibodies tested, with several cross-reacting with the related MAP2 protein, whereas the "oligomeric Tau" T22 antibody reacted with monomeric Tau by WB, thus calling into question its specificity to Tau oligomers. Despite the presumption that "total" Tau antibodies are agnostic to post-translational modifications, we found that phosphorylation partially inhibits binding for many such antibodies, including the popular Tau-5 clone. We further combine high-sensitivity reagents, mass-spectrometry proteomics and cDNA sequencing to demonstrate that presumptive Tau "knockout" human cells continue to express residual protein arising through exon skipping, providing evidence of previously unappreciated gene plasticity. Finally, probing of human brain samples with a large panel of antibodies revealed the presence of C-term-truncated versions of all main Tau brain isoforms in both control and tauopathy donors. Ultimately, we identify a validated panel of Tau antibodies that can be employed in Western blotting and/or immunohistochemistry to reliably detect even low levels of Tau expression with high selectivity. This work represents an extensive resource that will enable the re-interpretation of published data, improve reproducibility in Tau research, and overall accelerate scientific progress.
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Affiliation(s)
- Michael J Ellis
- JDRF/Wellcome Diabetes and Inflammation Laboratory, Nuffield Department of Medicine, Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Christiana Lekka
- Islet Biology Group, Department of Clinical & Biomedical Sciences, Exeter Centre of Excellence in Diabetes (EXCEED), University of Exeter, RILD Building, Exeter, UK
| | - Katie L Holden
- JDRF/Wellcome Diabetes and Inflammation Laboratory, Nuffield Department of Medicine, Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Hanna Tulmin
- JDRF/Wellcome Diabetes and Inflammation Laboratory, Nuffield Department of Medicine, Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Faheem Seedat
- JDRF/Wellcome Diabetes and Inflammation Laboratory, Nuffield Department of Medicine, Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
- Nuffield Department of Women's and Reproductive Health, Women's Centre, University of Oxford, John Radcliffe Hospital, Level 3, Oxford, UK
| | - Darragh P O'Brien
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Shalinee Dhayal
- Islet Biology Group, Department of Clinical & Biomedical Sciences, Exeter Centre of Excellence in Diabetes (EXCEED), University of Exeter, RILD Building, Exeter, UK
| | - Marie-Louise Zeissler
- Islet Biology Group, Department of Clinical & Biomedical Sciences, Exeter Centre of Excellence in Diabetes (EXCEED), University of Exeter, RILD Building, Exeter, UK
| | - Jakob G Knudsen
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Oxford, Radcliffe, UK
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Benedikt M Kessler
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Noel G Morgan
- Islet Biology Group, Department of Clinical & Biomedical Sciences, Exeter Centre of Excellence in Diabetes (EXCEED), University of Exeter, RILD Building, Exeter, UK
| | - John A Todd
- JDRF/Wellcome Diabetes and Inflammation Laboratory, Nuffield Department of Medicine, Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Sarah J Richardson
- Islet Biology Group, Department of Clinical & Biomedical Sciences, Exeter Centre of Excellence in Diabetes (EXCEED), University of Exeter, RILD Building, Exeter, UK
| | - M Irina Stefana
- JDRF/Wellcome Diabetes and Inflammation Laboratory, Nuffield Department of Medicine, Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
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Fischer I, Connors T, Bouyer J, Jin Y. The unique properties of Big tau in the visual system. Cytoskeleton (Hoboken) 2024. [PMID: 38761116 DOI: 10.1002/cm.21875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 03/29/2024] [Accepted: 04/26/2024] [Indexed: 05/20/2024]
Abstract
Tau is a microtubule associated protein that plays important roles in regulating the properties of microtubules and axonal transport, as well as tauopathies associated with toxic aggregates leading to neurodegenerative diseases. It is encoded by the MAPT gene forming multiple isoforms (45-60 kDa) by alternative splicing which are developmentally regulated. The high molecular weight (MW) tau isoform of 105 kDa, termed Big tau, was originally discovered in the peripheral nervous system (PNS) but later found in selective CNS areas. It contains an additional large exon 4a generating a long projecting domain of about 250 amino acids. Here we investigated the properties of Big tau in the visual system of rats, its distribution in retinal ganglion cells and the optic nerve as well as its developmental regulation using biochemical, molecular and histological analyses. We discovered that Big tau is expresses as a 95 kDa protein (termed middle MW) containing exons 4a, 6 as well as exon 10 which defines a 4 microtubule-binding repeats (4R). It lacks exons 2/3 but shares the extensive phosphorylation characteristic of other tau isoforms. Importantly, early in development the visual system expresses only the low MW isoform (3R) switching to both the low and middle MW isoforms (4R) in adult retinal ganglion neurons and their corresponding axons. This is a unique structure and expression pattern of Big tau, which we hypothesize is associated with the specific properties of the visual system different from what has been previously described in the PNS and other areas of the nervous system.
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Affiliation(s)
- Itzhak Fischer
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Theresa Connors
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Julien Bouyer
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Ying Jin
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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Zheng H, Sun H, Cai Q, Tai HC. The Enigma of Tau Protein Aggregation: Mechanistic Insights and Future Challenges. Int J Mol Sci 2024; 25:4969. [PMID: 38732197 PMCID: PMC11084794 DOI: 10.3390/ijms25094969] [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: 03/30/2024] [Revised: 04/20/2024] [Accepted: 04/23/2024] [Indexed: 05/13/2024] Open
Abstract
Tau protein misfolding and aggregation are pathological hallmarks of Alzheimer's disease and over twenty neurodegenerative disorders. However, the molecular mechanisms of tau aggregation in vivo remain incompletely understood. There are two types of tau aggregates in the brain: soluble aggregates (oligomers and protofibrils) and insoluble filaments (fibrils). Compared to filamentous aggregates, soluble aggregates are more toxic and exhibit prion-like transmission, providing seeds for templated misfolding. Curiously, in its native state, tau is a highly soluble, heat-stable protein that does not form fibrils by itself, not even when hyperphosphorylated. In vitro studies have found that negatively charged molecules such as heparin, RNA, or arachidonic acid are generally required to induce tau aggregation. Two recent breakthroughs have provided new insights into tau aggregation mechanisms. First, as an intrinsically disordered protein, tau is found to undergo liquid-liquid phase separation (LLPS) both in vitro and inside cells. Second, cryo-electron microscopy has revealed diverse fibrillar tau conformations associated with different neurodegenerative disorders. Nonetheless, only the fibrillar core is structurally resolved, and the remainder of the protein appears as a "fuzzy coat". From this review, it appears that further studies are required (1) to clarify the role of LLPS in tau aggregation; (2) to unveil the structural features of soluble tau aggregates; (3) to understand the involvement of fuzzy coat regions in oligomer and fibril formation.
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Affiliation(s)
| | | | | | - Hwan-Ching Tai
- State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, School of Public Health, Xiamen University, Xiamen 361102, China
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5
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Tanaka H, Martinez-Valbuena I, Forrest SL, Couto B, Reyes NG, Morales-Rivero A, Lee S, Li J, Karakani AM, Tang-Wai DF, Tator C, Khadadadi M, Sadia N, Tartaglia MC, Lang AE, Kovacs GG. Distinct involvement of the cranial and spinal nerves in progressive supranuclear palsy. Brain 2024; 147:1399-1411. [PMID: 37972275 PMCID: PMC10994524 DOI: 10.1093/brain/awad381] [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: 08/10/2023] [Revised: 10/08/2023] [Accepted: 10/26/2023] [Indexed: 11/19/2023] Open
Abstract
The most frequent neurodegenerative proteinopathies include diseases with deposition of misfolded tau or α-synuclein in the brain. Pathological protein aggregates in the PNS are well-recognized in α-synucleinopathies and have recently attracted attention as a diagnostic biomarker. However, there is a paucity of observations in tauopathies. To characterize the involvement of the PNS in tauopathies, we investigated tau pathology in cranial and spinal nerves (PNS-tau) in 54 tauopathy cases [progressive supranuclear palsy (PSP), n = 15; Alzheimer's disease (AD), n = 18; chronic traumatic encephalopathy (CTE), n = 5; and corticobasal degeneration (CBD), n = 6; Pick's disease, n = 9; limbic-predominant neuronal inclusion body 4-repeat tauopathy (LNT), n = 1] using immunohistochemistry, Gallyas silver staining, biochemistry, and seeding assays. Most PSP cases revealed phosphorylated and 4-repeat tau immunoreactive tau deposits in the PNS as follows: (number of tau-positive cases/available cases) cranial nerves III: 7/8 (88%); IX/X: 10/11 (91%); and XII: 6/6 (100%); anterior spinal roots: 10/10 (100%). The tau-positive inclusions in PSP often showed structures with fibrillary (neurofibrillary tangle-like) morphology in the axon that were also recognized with Gallyas silver staining. CBD cases rarely showed fine granular non-argyrophilic tau deposits. In contrast, tau pathology in the PNS was not evident in AD, CTE and Pick's disease cases. The single LNT case also showed tau pathology in the PNS. In PSP, the severity of PNS-tau involvement correlated with that of the corresponding nuclei, although, occasionally, p-tau deposits were present in the cranial nerves but not in the related brainstem nuclei. Not surprisingly, most of the PSP cases presented with eye movement disorder and bulbar symptoms, and some cases also showed lower-motor neuron signs. Using tau biosensor cells, for the first time we demonstrated seeding capacity of tau in the PNS. In conclusion, prominent PNS-tau distinguishes PSP from other tauopathies. The morphological differences of PNS-tau between PSP and CBD suggest that the tau pathology in PNS could reflect that in the central nervous system. The high frequency and early presence of tau lesions in PSP suggest that PNS-tau may have clinical and biomarker relevance.
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Affiliation(s)
- Hidetomo Tanaka
- Department of Laboratory Medicine and Pathobiology and Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Toronto, Ontario M5T 0S8, Canada
| | - Ivan Martinez-Valbuena
- Department of Laboratory Medicine and Pathobiology and Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Toronto, Ontario M5T 0S8, Canada
| | - Shelley L Forrest
- Department of Laboratory Medicine and Pathobiology and Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Toronto, Ontario M5T 0S8, Canada
- Laboratory Medicine Program and Krembil Brain Institute, University Health Network, Toronto, Ontario M5T 0S8, Canada
| | - Blas Couto
- Edmond J. Safra Program in Parkinson's Disease, Rossy Program for PSP Research and the Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, Toronto, Ontario M5T 2S8, Canada
| | - Nikolai Gil Reyes
- Edmond J. Safra Program in Parkinson's Disease, Rossy Program for PSP Research and the Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, Toronto, Ontario M5T 2S8, Canada
| | - Alonso Morales-Rivero
- University Health Network Memory Clinic, Toronto Western Hospital, Toronto, Ontario M5T 2S8, Canada
| | - Seojin Lee
- Department of Laboratory Medicine and Pathobiology and Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Toronto, Ontario M5T 0S8, Canada
| | - Jun Li
- Department of Laboratory Medicine and Pathobiology and Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Toronto, Ontario M5T 0S8, Canada
| | - Ali M Karakani
- Department of Laboratory Medicine and Pathobiology and Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Toronto, Ontario M5T 0S8, Canada
| | - David F Tang-Wai
- University Health Network Memory Clinic, Toronto Western Hospital, Toronto, Ontario M5T 2S8, Canada
- Department of Medicine/Division of Neurology, University of Toronto, Toronto, Ontario M5S 3H2, Canada
- Krembil Brain Institute, Toronto Western Hospital, Toronto, Ontario M5T 2S8, Canada
| | - Charles Tator
- Krembil Brain Institute, Toronto Western Hospital, Toronto, Ontario M5T 2S8, Canada
- Canadian Concussion Centre, Krembil Brain Institute, University Health Network, Toronto, Ontario M5T 0S8, Canada
| | - Mozhgan Khadadadi
- Canadian Concussion Centre, Krembil Brain Institute, University Health Network, Toronto, Ontario M5T 0S8, Canada
| | - Nusrat Sadia
- Canadian Concussion Centre, Krembil Brain Institute, University Health Network, Toronto, Ontario M5T 0S8, Canada
| | - Maria Carmela Tartaglia
- University Health Network Memory Clinic, Toronto Western Hospital, Toronto, Ontario M5T 2S8, Canada
- Department of Medicine/Division of Neurology, University of Toronto, Toronto, Ontario M5S 3H2, Canada
- Krembil Brain Institute, Toronto Western Hospital, Toronto, Ontario M5T 2S8, Canada
- Canadian Concussion Centre, Krembil Brain Institute, University Health Network, Toronto, Ontario M5T 0S8, Canada
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario M5T 0S8, Canada
| | - Anthony E Lang
- Edmond J. Safra Program in Parkinson's Disease, Rossy Program for PSP Research and the Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, Toronto, Ontario M5T 2S8, Canada
- Department of Medicine/Division of Neurology, University of Toronto, Toronto, Ontario M5S 3H2, Canada
- Krembil Brain Institute, Toronto Western Hospital, Toronto, Ontario M5T 2S8, Canada
| | - Gabor G Kovacs
- Department of Laboratory Medicine and Pathobiology and Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Toronto, Ontario M5T 0S8, Canada
- Department of Medicine/Division of Neurology, University of Toronto, Toronto, Ontario M5S 3H2, Canada
- Krembil Brain Institute, Toronto Western Hospital, Toronto, Ontario M5T 2S8, Canada
- Laboratory Medicine Program, University Health Network, Toronto, Ontario M5T 0S8, Canada
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Lane-Donovan C, Boxer AL. Disentangling tau: One protein, many therapeutic approaches. Neurotherapeutics 2024; 21:e00321. [PMID: 38278659 PMCID: PMC10963923 DOI: 10.1016/j.neurot.2024.e00321] [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: 10/31/2023] [Revised: 01/09/2024] [Accepted: 01/09/2024] [Indexed: 01/28/2024] Open
Abstract
The tauopathies encompass over 20 adult neurodegenerative diseases and are characterized by the dysfunction and accumulation of insoluble tau protein. Among them, Alzheimer's disease, frontotemporal dementia, and progressive supranuclear palsy collectively impact millions of patients and their families worldwide. Despite years of drug development using a variety of mechanisms of action, no therapeutic directed against tau has been approved for clinical use. This raises important questions about our current model of tau pathology and invites thoughtful consideration of our approach to nonclinical models and clinical trial design. In this article, we review what is known about the biology and genetics of tau, placing it in the context of current and failed clinical trials. We highlight potential reasons for the lack of success to date and offer suggestions for new pathways in therapeutic development. Overall, our viewpoint to the future is optimistic for this important group of neurodegenerative diseases.
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Affiliation(s)
- Courtney Lane-Donovan
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA 94158, USA.
| | - Adam L Boxer
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA 94158, USA
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Fischer I. Big tau: What, how, where and why. Cytoskeleton (Hoboken) 2024; 81:10-15. [PMID: 37578198 DOI: 10.1002/cm.21772] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/15/2023]
Abstract
Over the last 50 years the different isoforms of tau proteins (45-60 kDa) have been a focus of research because of their roles in modulating the dynamic properties of microtubules shaping the structure and function of neurons but also becoming a center of attention in the pathology of neurodegeneration associated with tauopathies. Much less attention has been given to Big tau, a unique isoform containing exon 4a encoding about 250 amino acids to form a much longer projection domain of a protein of 110 kDa. Big tau is expressed in peripheral neurons and selective regions of the central nervous system in a defined transition during postnatal developmental stages. Although Big tau was discovered 30 years ago, there has been a persistent gap of knowledge regarding its physiological properties and pathological implications. This Perspective summarizes the progress so far in defining the structure and expression of Big tau within and outside the nervous system, proposes a role for Big tau in improving axonal transport in projecting axons, considers its potential in averting tau aggregation in tauopathies and highlights the need for further progress.
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Affiliation(s)
- Itzhak Fischer
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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