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Chu S, Xie X, Payan C, Stochaj U. Valosin containing protein (VCP): initiator, modifier, and potential drug target for neurodegenerative diseases. Mol Neurodegener 2023; 18:52. [PMID: 37545006 PMCID: PMC10405438 DOI: 10.1186/s13024-023-00639-y] [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: 02/20/2023] [Accepted: 06/27/2023] [Indexed: 08/08/2023] Open
Abstract
The AAA+ ATPase valosin containing protein (VCP) is essential for cell and organ homeostasis, especially in cells of the nervous system. As part of a large network, VCP collaborates with many cofactors to ensure proteostasis under normal, stress, and disease conditions. A large number of mutations have revealed the importance of VCP for human health. In particular, VCP facilitates the dismantling of protein aggregates and the removal of dysfunctional organelles. These are critical events to prevent malfunction of the brain and other parts of the nervous system. In line with this idea, VCP mutants are linked to the onset and progression of neurodegeneration and other diseases. The intricate molecular mechanisms that connect VCP mutations to distinct brain pathologies continue to be uncovered. Emerging evidence supports the model that VCP controls cellular functions on multiple levels and in a cell type specific fashion. Accordingly, VCP mutants derail cellular homeostasis through several mechanisms that can instigate disease. Our review focuses on the association between VCP malfunction and neurodegeneration. We discuss the latest insights in the field, emphasize open questions, and speculate on the potential of VCP as a drug target for some of the most devastating forms of neurodegeneration.
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Affiliation(s)
- Siwei Chu
- Department of Physiology, McGill University, Montreal, HG3 1Y6, Canada
| | - Xinyi Xie
- Department of Physiology, McGill University, Montreal, HG3 1Y6, Canada
| | - Carla Payan
- Department of Physiology, McGill University, Montreal, HG3 1Y6, Canada
| | - Ursula Stochaj
- Department of Physiology, McGill University, Montreal, HG3 1Y6, Canada.
- Quantitative Life Sciences Program, McGill University, Montreal, Canada.
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Ryder BD, Wydorski PM, Hou Z, Joachimiak LA. Chaperoning shape-shifting tau in disease. Trends Biochem Sci 2022; 47:301-313. [PMID: 35045944 DOI: 10.1016/j.tibs.2021.12.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 02/07/2023]
Abstract
Many neurodegenerative diseases, including Alzheimer's, originate from the conversion of proteins into pathogenic conformations. The microtubule-associated protein tau converts into β-sheet-rich amyloid conformations, which underlie pathology in over 25 related tauopathies. Structural studies of tau amyloid fibrils isolated from human tauopathy tissues have revealed that tau adopts diverse structural polymorphs, each linked to a different disease. Molecular chaperones play central roles in regulating tau function and amyloid assembly in disease. New data supports the model that chaperones selectively recognize different conformations of tau to limit the accumulation of proteotoxic species. The challenge now is to understand how chaperones influence disease processes across different tauopathies, which will help guide the development of novel conformation-specific diagnostic and therapeutic strategies.
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Affiliation(s)
- Bryan D Ryder
- Molecular Biophysics Graduate Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Center for Alzheimer's and Neurodegenerative Diseases, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Pawel M Wydorski
- Molecular Biophysics Graduate Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Center for Alzheimer's and Neurodegenerative Diseases, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Zhiqiang Hou
- Center for Alzheimer's and Neurodegenerative Diseases, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Lukasz A Joachimiak
- Center for Alzheimer's and Neurodegenerative Diseases, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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Ando K, Maruko-Otake A, Ohtake Y, Hayashishita M, Sekiya M, Iijima KM. Stabilization of Microtubule-Unbound Tau via Tau Phosphorylation at Ser262/356 by Par-1/MARK Contributes to Augmentation of AD-Related Phosphorylation and Aβ42-Induced Tau Toxicity. PLoS Genet 2016; 12:e1005917. [PMID: 27023670 PMCID: PMC4811436 DOI: 10.1371/journal.pgen.1005917] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 02/15/2016] [Indexed: 12/31/2022] Open
Abstract
Abnormal accumulation of the microtubule-interacting protein tau is associated with neurodegenerative diseases including Alzheimer’s disease (AD). β-amyloid (Aβ) lies upstream of abnormal tau behavior, including detachment from microtubules, phosphorylation at several disease-specific sites, and self-aggregation into toxic tau species in AD brains. To prevent the cascade of events leading to neurodegeneration in AD, it is essential to elucidate the mechanisms underlying the initial events of tau mismetabolism. Currently, however, these mechanisms remain unclear. In this study, using transgenic Drosophila co-expressing human tau and Aβ, we found that tau phosphorylation at AD-related Ser262/356 stabilized microtubule-unbound tau in the early phase of tau mismetabolism, leading to neurodegeneration. Aβ increased the level of tau detached from microtubules, independent of the phosphorylation status at GSK3-targeted SP/TP sites. Such mislocalized tau proteins, especially the less phosphorylated species, were stabilized by phosphorylation at Ser262/356 via PAR-1/MARK. Levels of Ser262 phosphorylation were increased by Aβ42, and blocking this stabilization of tau suppressed Aβ42-mediated augmentation of tau toxicity and an increase in the levels of tau phosphorylation at the SP/TP site Thr231, suggesting that this process may be involved in AD pathogenesis. In contrast to PAR-1/MARK, blocking tau phosphorylation at SP/TP sites by knockdown of Sgg/GSK3 did not reduce tau levels, suppress tau mislocalization to the cytosol, or diminish Aβ-mediated augmentation of tau toxicity. These results suggest that stabilization of microtubule-unbound tau by phosphorylation at Ser262/356 via the PAR-1/MARK may act in the initial steps of tau mismetabolism in AD pathogenesis, and that such tau species may represent a potential therapeutic target for AD. Alzheimer’s disease (AD) is the most common cause of dementia resulting from progressive neuron loss. Two proteins, β-amyloid (Aβ) and tau, accumulate in AD brains and are involved in AD pathogenesis. In healthy neurons, tau binds to microtubules to regulate its stability; in AD brains, however, tau is detached from microtubules and phosphorylated at multiple sites. Such abnormal tau behavior, which is likely to be triggered by Aβ, results in generation of pathological tau species that mediate neuron loss. However, the detailed mechanisms underlying this event remain incompletely understood. Using transgenic flies expressing human tau and Aβ as a model system, we found that tau phosphorylation at specific AD-related sites stabilized microtubule-unbound tau in the early phase of tau mismetabolism to generate toxic tau species. Moreover, this process is critical for Aβ to promote subsequent tau phosphorylation and neurodegeneration. Our results reveal a critical step in the initiation of tau mismetabolism, and this process may represent a potential therapeutic target for AD.
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Affiliation(s)
- Kanae Ando
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo, Japan
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
- * E-mail: (KA); (KMI)
| | - Akiko Maruko-Otake
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Yosuke Ohtake
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Motoki Hayashishita
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo, Japan
| | - Michiko Sekiya
- Department of Alzheimer’s Disease Research, National Center for Geriatrics and Gerontology, Obu, Aichi, Japan
| | - Koichi M. Iijima
- Department of Alzheimer’s Disease Research, National Center for Geriatrics and Gerontology, Obu, Aichi, Japan
- * E-mail: (KA); (KMI)
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Johnson AE, Shu H, Hauswirth AG, Tong A, Davis GW. VCP-dependent muscle degeneration is linked to defects in a dynamic tubular lysosomal network in vivo. eLife 2015; 4. [PMID: 26167652 PMCID: PMC4574298 DOI: 10.7554/elife.07366] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 07/11/2015] [Indexed: 12/25/2022] Open
Abstract
Lysosomes are classically viewed as vesicular structures to which cargos are delivered for degradation. Here, we identify a network of dynamic, tubular lysosomes that extends throughout Drosophila muscle, in vivo. Live imaging reveals that autophagosomes merge with tubular lysosomes and that lysosomal membranes undergo extension, retraction, fusion and fission. The dynamics and integrity of this tubular lysosomal network requires VCP, an AAA-ATPase that, when mutated, causes degenerative diseases of muscle, bone and neurons. We show that human VCP rescues the defects caused by loss of Drosophila VCP and overexpression of disease relevant VCP transgenes dismantles tubular lysosomes, linking tubular lysosome dysfunction to human VCP-related diseases. Finally, disruption of tubular lysosomes correlates with impaired autophagosome-lysosome fusion, increased cytoplasmic poly-ubiquitin aggregates, lipofuscin material, damaged mitochondria and impaired muscle function. We propose that VCP sustains sarcoplasmic proteostasis, in part, by controlling the integrity of a dynamic tubular lysosomal network. DOI:http://dx.doi.org/10.7554/eLife.07366.001 Mutations in a gene that produces a protein called Valosin-containing protein (VCP for short) causes degenerative diseases that affect the brain, muscle and bone. In nearly half of the individuals with these VCP-related diseases—which can also result in dementia, Paget's disease of the bone and amyotrophic lateral sclerosis (ALS)—the first symptom is muscle weakness. Currently, very little is known about how VCP affects muscles. Patients with VCP-related diseases often have problems clearing damaged proteins from their cells, and recent research suggests that VCP is important for forming a cellular structure known as a lysosome. Lysosomes contain powerful enzymes that destroy damaged proteins and other cellular structures that would otherwise accumulate in the cells. In most cells, lysosomes look like bubble-like compartments called vesicles. However, in some types of cells lysosomes have been observed to form a network of tubules that extend throughout the cell interior. However, it remains unclear what these tubules do, how they form in cells and whether they are altered in disease. Johnson et al. analyzed lysosomes in the muscle of the fruit fly species Drosophila melanogaster and discovered that lysosomes were in the form of a network of tubules that spread throughout each muscle cell. These tubules constantly changed in living muscles; extending, retracting, breaking and merging to form a large tubular lysosome network. When Johnson et al. reduced the amount of VCP produced by the muscle cells, via a method called RNA interference, the lysosome tubules broke down into vesicles that were no longer constantly changing. Modifying these defective fly muscle cells so that they produced the human VCP protein caused the tubules to form again. These results suggest that the human and fly VCP proteins are very similar and that they play a key role in either the ability of lysosomes to form tubules or the maintenance of existing tubules. Johnson et al. then engineered flies to produce a version of the VCP protein that had mutations commonly seen in individuals with degenerative diseases. Lysosome tubules did not form correctly in the muscle cells of these flies. These flies also had other abnormalities; for example, their cells showed a great build-up of damaged proteins, and their ability to move their muscles was weaker. These findings suggest that a network of lysosomal tubules is necessary for healthy muscle cells, but how and why these tubular networks are formed or maintained is still mysterious. What causes lysosomal membranes to form tubules? How do they break and fuse? And why are they necessary? Genetic experiments in fruit flies will be a great place to discover these mechanisms and understand the links to degenerative diseases in humans. DOI:http://dx.doi.org/10.7554/eLife.07366.002
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Affiliation(s)
- Alyssa E Johnson
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Huidy Shu
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Anna G Hauswirth
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Amy Tong
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Graeme W Davis
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
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Chapman E, Maksim N, de la Cruz F, La Clair JJ. Inhibitors of the AAA+ chaperone p97. Molecules 2015; 20:3027-49. [PMID: 25685910 PMCID: PMC4576884 DOI: 10.3390/molecules20023027] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 02/03/2015] [Indexed: 12/22/2022] Open
Abstract
It is remarkable that a pathway as ubiquitous as protein quality control can be targeted to treat cancer. Bortezomib, an inhibitor of the proteasome, was first approved by the US Food and Drug Administration (FDA) more than 10 years ago to treat refractory myeloma and later extended to lymphoma. Its use has increased the survival rate of myeloma patients by as much as three years. This success was followed with the recent accelerated approval of the natural product derived proteasome inhibitor carfilzomib (Kyprolis®), which is used to treat patients with bortezomib-resistant multiple myeloma. The success of these two drugs has validated protein quality control as a viable target to fight select cancers, but begs the question why are proteasome inhibitors limited to lymphoma and myeloma? More recently, these limitations have encouraged the search for additional targets within the protein quality control system that might offer heightened cancer cell specificity, enhanced clinical utility, a lower rate of resistance, reduced toxicity, and mitigated side effects. One promising target is p97, an ATPase associated with various cellular activities (AAA+) chaperone. p97 figures prominently in protein quality control as well as serving a variety of other cellular functions associated with cancer. More than a decade ago, it was determined that up-regulation of p97 in many forms of cancer correlates with a poor clinical outcome. Since these initial discoveries, a mechanistic explanation for this observation has been partially illuminated, but details are lacking. Understandably, given this clinical correlation, myriad roles within the cell, and its importance in protein quality control, p97 has emerged as a potential therapeutic target. This review provides an overview of efforts towards the discovery of small molecule inhibitors of p97, offering a synopsis of efforts that parallel the excellent reviews that currently exist on p97 structure, function, and physiology.
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Affiliation(s)
- Eli Chapman
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721-0207, USA.
| | - Nick Maksim
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721-0207, USA.
| | - Fabian de la Cruz
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721-0207, USA.
| | - James J La Clair
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721-0207, USA.
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Dominy SS, Brown JN, Ryder MI, Gritsenko M, Jacobs JM, Smith RD. Proteomic analysis of saliva in HIV-positive heroin addicts reveals proteins correlated with cognition. PLoS One 2014; 9:e89366. [PMID: 24717448 PMCID: PMC3981673 DOI: 10.1371/journal.pone.0089366] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 01/21/2014] [Indexed: 02/07/2023] Open
Abstract
The prevalence of HIV-associated neurocognitive disorders (HAND) remains high despite effective antiretroviral therapies. Multiple etiologies have been proposed over the last several years to account for this phenomenon, including the neurotoxic effects of antiretrovirals and co-morbid substance abuse; however, no underlying molecular mechanism has been identified. Emerging evidence in several fields has linked the gut to brain diseases, but the effect of the gut on the brain during HIV infection has not been explored. Saliva is the most accessible gut biofluid, and is therefore of great scientific interest for diagnostic and prognostic purposes. This study presents a longitudinal, liquid chromatography-mass spectrometry-based quantitative proteomics study investigating saliva samples taken from 8 HIV-positive (HIV+), 11 −negative (HIV−) heroin addicts. In addition, saliva samples were investigated from 11 HIV−, non-heroin addicted healthy controls. In the HIV+ group, 58 proteins were identified that show significant correlations with cognitive scores, implicating disruption of protein quality control pathways by HIV. Notably, only one protein from the HIV− heroin addict cohort showed a significant correlation with cognitive scores, and no proteins correlated with cognitive scores in the healthy control group. In addition, the majority of correlated proteins have been shown to be associated with exosomes, allowing us to propose that the salivary glands and/or oral epithelium may modulate brain function during HIV infection through the release of discrete packets of proteins in the form of exosomes.
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Affiliation(s)
- Stephen S. Dominy
- Department of Psychiatry, University of California San Francisco, San Francisco, California, United States of America
- * E-mail: (SD); (RS)
| | - Joseph N. Brown
- Biological Sciences Division, Pacific Northwest National Laboratories, Richland, Washington, United States of America
| | - Mark I. Ryder
- Division of Periodontology, Department of Orofacial Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - Marina Gritsenko
- Biological Sciences Division, Pacific Northwest National Laboratories, Richland, Washington, United States of America
| | - Jon M. Jacobs
- Biological Sciences Division, Pacific Northwest National Laboratories, Richland, Washington, United States of America
| | - Richard D. Smith
- Biological Sciences Division, Pacific Northwest National Laboratories, Richland, Washington, United States of America
- * E-mail: (SD); (RS)
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Chesser AS, Pritchard SM, Johnson GVW. Tau clearance mechanisms and their possible role in the pathogenesis of Alzheimer disease. Front Neurol 2013; 4:122. [PMID: 24027553 PMCID: PMC3759803 DOI: 10.3389/fneur.2013.00122] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/15/2013] [Indexed: 12/24/2022] Open
Abstract
One of the defining pathological features of Alzheimer disease (AD) is the intraneuronal accumulation of tau. The tau that forms these accumulations is altered both posttranslationally and conformationally, and there is now significant evidence that soluble forms of these modified tau species are the toxic entities rather than the insoluble neurofibrillary tangles. However there is still noteworthy debate concerning which specific pathological forms of tau are the contributors to neuronal dysfunction and death in AD. Given that increases in aberrant forms of tau play a role in the neurodegeneration process in AD, there is growing interest in understanding the degradative pathways that remove tau from the cell, and the selectivity of these different pathways for various forms of tau. Indeed, one can speculate that deficits in a pathway that selectively removes certain pathological forms of tau could play a pivotal role in AD. In this review we will discuss the different proteolytic and degradative machineries that may be involved in removing tau from the cell. How deficits in these different degradative pathways may contribute to abnormal accumulation of tau in AD will also be considered. In addition, the issue of the selective targeting of specific tau species to a given degradative pathway for clearance from the cell will be addressed.
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Affiliation(s)
- Adrianne S Chesser
- Neuroscience Graduate Program, Department of Anesthesiology, University of Rochester , Rochester, NY , USA
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