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Salcedo-Tacuma D, Asad N, Howells G, Anderson R, Smith DM. Proteasome hyperactivation rewires the proteome enhancing stress resistance, proteostasis, lipid metabolism and ERAD in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.04.588128. [PMID: 38617285 PMCID: PMC11014606 DOI: 10.1101/2024.04.04.588128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Proteasome dysfunction is implicated in the pathogenesis of neurodegenerative diseases and age-related proteinopathies. Using a C. elegans model, we demonstrate that 20S proteasome hyperactivation, facilitated by 20S gate-opening, accelerates the targeting of intrinsically disordered proteins. This leads to increased protein synthesis, extensive rewiring of the proteome and transcriptome, enhanced oxidative stress defense, accelerated lipid metabolism, and peroxisome proliferation. It also promotes ER-associated degradation (ERAD) of aggregation-prone proteins, such as alpha-1 antitrypsin (ATZ) and various lipoproteins. Notably, our results reveal that 20S proteasome hyperactivation suggests a novel role in ERAD with broad implications for proteostasis-related disorders, simultaneously affecting lipid homeostasis and peroxisome proliferation. Furthermore, the enhanced cellular capacity to mitigate proteostasis challenges, alongside unanticipated acceleration of lipid metabolism is expected to contribute to the longevity phenotype of this mutant. Remarkably, the mechanism of longevity induced by 20S gate opening appears unique, independent of known longevity and stress-resistance pathways. These results support the therapeutic potential of 20S proteasome activation in mitigating proteostasis-related disorders broadly and provide new insights into the complex interplay between proteasome activity, cellular health, and aging.
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Affiliation(s)
- David Salcedo-Tacuma
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
| | - Nadeeem. Asad
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
| | - Giovanni Howells
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
| | - Raymond Anderson
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
| | - David M. Smith
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
- Department of Neuroscience, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, West Virginia, USA
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2
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Rizo T, Gebhardt L, Riedlberger J, Eberhardt E, Fester L, Alansary D, Winkler J, Turan S, Arnold P, Niemeyer BA, Fischer MJM, Winner B. Store-operated calcium entry is reduced in spastin-linked hereditary spastic paraplegia. Brain 2022; 145:3131-3146. [PMID: 36103408 PMCID: PMC9473359 DOI: 10.1093/brain/awac122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/17/2022] [Accepted: 03/22/2022] [Indexed: 01/04/2023] Open
Abstract
Pathogenic variants in SPAST, the gene coding for spastin, are the single most common cause of hereditary spastic paraplegia, a progressive motor neuron disease. Spastin regulates key cellular functions, including microtubule-severing and endoplasmic reticulum-morphogenesis. However, it remains unclear how alterations in these cellular functions due to SPAST pathogenic variants result in motor neuron dysfunction. Since spastin influences both microtubule network and endoplasmic reticulum structure, we hypothesized that spastin is necessary for the regulation of Ca2+ homeostasis via store-operated calcium entry. Here, we show that the lack of spastin enlarges the endoplasmic reticulum and reduces store-operated calcium entry. In addition, elevated levels of different spastin variants induced clustering of STIM1 within the endoplasmic reticulum, altered the transport of STIM1 to the plasma membrane and reduced store-operated calcium entry, which could be rescued by exogenous expression of STIM1. Importantly, store-operated calcium entry was strongly reduced in induced pluripotent stem cell-derived neurons from hereditary spastic paraplegia patients with pathogenic variants in SPAST resulting in spastin haploinsufficiency. These neurons developed axonal swellings in response to lack of spastin. We were able to rescue both store-operated calcium entry and axonal swellings in SPAST patient neurons by restoring spastin levels, using CRISPR/Cas9 to correct the pathogenic variants in SPAST. These findings demonstrate that proper amounts of spastin are a key regulatory component for store-operated calcium entry mediated Ca2+ homeostasis and suggest store-operated calcium entry as a disease relevant mechanism of spastin-linked motor neuron disease.
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Affiliation(s)
- Tania Rizo
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Lisa Gebhardt
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Julia Riedlberger
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Esther Eberhardt
- Present address: Department of Anesthesiology, RWTH Aachen University, 52074 Aachen, Germany
| | - Lars Fester
- Institute of Anatomy and Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Dalia Alansary
- Molecular Biophysics, University of Saarland, Center for Integrative Physiology and Molecular Medicine, 66421 Homburg/Saar, Germany
| | - Jürgen Winkler
- Department of Molecular Neurology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany,Center of Rare Diseases Erlangen (ZSEER), Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Soeren Turan
- Institute of Biochemistry (Emil-Fischer-Center), Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Philipp Arnold
- Institute of Anatomy, Functional and Clinical Anatomy, Friedrich-Alexander-University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | | | | | - Beate Winner
- Correspondence to: Beate Winner Department of Stem Cell Biology Friedrich-Alexander University Erlangen-Nürnberg Glückstraße 6 91054 Erlangen, Germany E-mail:
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Cada AK, Pavlin MR, Castillo JP, Tong AB, Larsen KP, Ren X, Yokom AL, Tsai FC, Shiah JV, Bassereau PM, Bustamante CJ, Hurley JH. Friction-driven membrane scission by the human ESCRT-III proteins CHMP1B and IST1. Proc Natl Acad Sci U S A 2022; 119:e2204536119. [PMID: 35858336 PMCID: PMC9303997 DOI: 10.1073/pnas.2204536119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 05/31/2022] [Indexed: 12/15/2022] Open
Abstract
The endosomal sorting complexes required for transport (ESCRT) system is an ancient and ubiquitous membrane scission machinery that catalyzes the budding and scission of membranes. ESCRT-mediated scission events, exemplified by those involved in the budding of HIV-1, are usually directed away from the cytosol ("reverse topology"), but they can also be directed toward the cytosol ("normal topology"). The ESCRT-III subunits CHMP1B and IST1 can coat and constrict positively curved membrane tubes, suggesting that these subunits could catalyze normal topology membrane severing. CHMP1B and IST1 bind and recruit the microtubule-severing AAA+ ATPase spastin, a close relative of VPS4, suggesting that spastin could have a VPS4-like role in normal-topology membrane scission. Here, we reconstituted the process in vitro using membrane nanotubes pulled from giant unilamellar vesicles using an optical trap in order to determine whether CHMP1B and IST1 are capable of membrane severing on their own or in concert with VPS4 or spastin. CHMP1B and IST1 copolymerize on membrane nanotubes, forming stable scaffolds that constrict the tubes, but do not, on their own, lead to scission. However, CHMP1B-IST1 scaffolded tubes were severed when an additional extensional force was applied, consistent with a friction-driven scission mechanism. We found that spastin colocalized with CHMP1B-enriched sites but did not disassemble the CHMP1B-IST1 coat from the membrane. VPS4 resolubilized CHMP1B and IST1 without leading to scission. These observations show that the CHMP1B-IST1 ESCRT-III combination is capable of severing membranes by a friction-driven mechanism that is independent of VPS4 and spastin.
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Affiliation(s)
- A. King Cada
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
| | - Mark R. Pavlin
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
- Graduate Group in Biophysics, University of California, Berkeley, CA 94720
| | - Juan P. Castillo
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Alexander B. Tong
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Kevin P. Larsen
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
| | - Xuefeng Ren
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
| | - Adam L. Yokom
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
| | - Feng-Ching Tsai
- Laboratoire Physico-Chimie Curie, Institut Curie, Université Paris Sciences & Letters, CNRS UMR168, Sorbonne Université, Paris, 75005 France
| | - Jamie V. Shiah
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
| | - Patricia M. Bassereau
- Laboratoire Physico-Chimie Curie, Institut Curie, Université Paris Sciences & Letters, CNRS UMR168, Sorbonne Université, Paris, 75005 France
| | - Carlos J. Bustamante
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
- Graduate Group in Biophysics, University of California, Berkeley, CA 94720
- Department of Chemistry, University of California, Berkeley, CA 94720
- Department of Physics, University of California, Berkeley, CA 94720
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
- Kavli Energy Nanoscience Institute, University of California, Berkeley, CA 94720
| | - James H. Hurley
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
- Graduate Group in Biophysics, University of California, Berkeley, CA 94720
- Helen Wills Institute of Neuroscience, University of California, Berkeley, CA 94720
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Liu Q, Zhang G, Ji Z, Lin H. Molecular and cellular mechanisms of spastin in neural development and disease (Review). Int J Mol Med 2021; 48:218. [PMID: 34664680 PMCID: PMC8547542 DOI: 10.3892/ijmm.2021.5051] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/29/2021] [Indexed: 12/26/2022] Open
Abstract
Spastin is a microtubule (MT)‑severing enzyme identified from mutations of hereditary spastic paraplegia in 1999 and extensive studies indicate its vital role in various cellular activities. In the past two decades, efforts have been made to understand the underlying molecular mechanisms of how spastin is linked to neural development and disease. Recent studies on spastin have unraveled the mechanistic processes of its MT‑severing activity and revealed that spastin acts as an MT amplifier to mediate its remodeling, thus providing valuable insight into the molecular roles of spastin under physiological conditions. In addition, recent research has revealed multiple novel molecular mechanisms of spastin in cellular biological pathways, including endoplasmic reticulum shaping, calcium trafficking, fatty acid trafficking, as well as endosomal fission and trafficking. These processes are closely involved in axonal and dendritic development and maintenance. The current review presents recent biological advances regarding the molecular mechanisms of spastin at the cellular level and provides insight into how it affects neural development and disease.
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Affiliation(s)
- Qiuling Liu
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, P.R. China
| | - Guowei Zhang
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, P.R. China
| | - Zhisheng Ji
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, P.R. China
| | - Hongsheng Lin
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, P.R. China
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5
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Tadepalle N, Rugarli EI. Lipid Droplets in the Pathogenesis of Hereditary Spastic Paraplegia. Front Mol Biosci 2021; 8:673977. [PMID: 34041268 PMCID: PMC8141572 DOI: 10.3389/fmolb.2021.673977] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/26/2021] [Indexed: 12/21/2022] Open
Abstract
Hereditary spastic paraplegias (HSPs) are genetically heterogeneous conditions caused by the progressive dying back of the longest axons in the central nervous system, the corticospinal axons. A wealth of data in the last decade has unraveled disturbances of lipid droplet (LD) biogenesis, maturation, turnover and contact sites in cellular and animal models with perturbed expression and function of HSP proteins. As ubiquitous organelles that segregate neutral lipid into a phospholipid monolayer, LDs are at the cross-road of several processes including lipid metabolism and trafficking, energy homeostasis, and stress signaling cascades. However, their role in brain cells, especially in neurons remains enigmatic. Here, we review experimental findings linking LD abnormalities to defective function of proteins encoded by HSP genes, and discuss arising questions in the context of the pathogenesis of HSP.
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Affiliation(s)
- Nimesha Tadepalle
- Molecular and Cell Biology Laboratory, Salk Institute of Biological Sciences, La Jolla, CA, United States
| | - Elena I Rugarli
- Institute for Genetics, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany.,Center for Molecular Medicine (CMMC),Cologne, Germany
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6
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Sakoe K, Shioda N, Matsuura T. A newly identified NES sequence present in spastin regulates its subcellular localization and microtubule severing activity. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1868:118862. [PMID: 32979422 DOI: 10.1016/j.bbamcr.2020.118862] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 09/11/2020] [Accepted: 09/19/2020] [Indexed: 01/01/2023]
Abstract
Spastin, a microtubule-severing AAA ATPase, regulates microtubule dynamics and plays important roles in cell division and neurogenesis. Mutations in the spastin-coding gene SPAST lead to neurodegenerative disorders and cause spastic paraplegia type 4. Spastin has two main isoforms, M1 and M87, that differ only in the presence or absence of 86 N-terminal amino acids and have alternative splicing variants that lack exon4. The N-terminal region of M1 contains a hydrophobic domain, nuclear localization signal (NLS), and nuclear export signal (NES), which partly explains the differences in the two isoforms' localization. However, the mechanisms involved in regulating isoform localization, and the effects of localization on spastin functions are not fully understood. We found endogenous M1 and M87 shuttled between the nucleus and cytoplasm during the cell cycle. We identified a NES (amino acids 195-204) that spans the microtubule-interacting and endosomal-trafficking domain and exon4 region. Furthermore, the NES sequence contains both the coiled-coil and exon4 region of spastin isoforms. Highly conserved leucine 195 in exon3 and the two residues in exon4 are crucial for predicted coiled-coil formation. Mutations in NES or leptomycin B treatment reduced cytoplasmic localization and microtubule fragmentation in M87 rather than in M1. Phosphomimetic mutation of threonine 306 adjacent to the NLS (amino acids 309-312) inhibited nuclear transport of M87. Our results indicate that the newly identified NES in the spastin isoforms containing exon4 regulates the subcellular localization of spastin in coordination with NLS controlled by the phosphorylation state of spastin, and is involved in microtubule severing.
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Affiliation(s)
- Kumi Sakoe
- Division of Neurology, Department of Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan.
| | - Norifumi Shioda
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto 860-0811, Japan
| | - Tohru Matsuura
- Division of Neurology, Department of Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
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7
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Spastin mutations impair coordination between lipid droplet dispersion and reticulum. PLoS Genet 2020; 16:e1008665. [PMID: 32315314 PMCID: PMC7173978 DOI: 10.1371/journal.pgen.1008665] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 02/12/2020] [Indexed: 12/22/2022] Open
Abstract
Lipid droplets (LD) are affected in multiple human disorders. These highly dynamic organelles are involved in many cellular roles. While their intracellular dispersion is crucial to ensure their function and other organelles-contact, underlying mechanisms are still unclear. Here we show that Spastin, one of the major proteins involved in Hereditary Spastic Paraplegia (HSP), controls LD dispersion. Spastin depletion in zebrafish affects metabolic properties and organelle dynamics. These functions are ensured by a conserved complex set of splice variants. M1 isoforms determine LD dispersion in the cell by orchestrating endoplasmic reticulum (ER) shape along microtubules (MTs). To further impact LD fate, Spastin modulates transcripts levels and subcellular location of other HSP key players, notably Seipin and REEP1. In pathological conditions, mutations in human Spastin M1 disrupt this mechanism and impacts LD network. Spastin depletion influences not only other key proteins but also modulates specific neutral lipids and phospholipids, revealing an impact on membrane and organelle components. Altogether our results show that Spastin and its partners converge in a common machinery that coordinates LD dispersion and ER shape along MTs. Any alteration of this system results in HSP clinical features and impacts lipids profile, thus opening new avenues for novel biomarkers of HSP.
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8
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Han H, Schubert HL, McCullough J, Monroe N, Purdy MD, Yeager M, Sundquist WI, Hill CP. Structure of spastin bound to a glutamate-rich peptide implies a hand-over-hand mechanism of substrate translocation. J Biol Chem 2019; 295:435-443. [PMID: 31767681 DOI: 10.1074/jbc.ac119.009890] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 11/11/2019] [Indexed: 11/06/2022] Open
Abstract
Many members of the AAA+ ATPase family function as hexamers that unfold their protein substrates. These AAA unfoldases include spastin, which plays a critical role in the architecture of eukaryotic cells by driving the remodeling and severing of microtubules, which are cytoskeletal polymers of tubulin subunits. Here, we demonstrate that a human spastin binds weakly to unmodified peptides from the C-terminal segment of human tubulin α1A/B. A peptide comprising alternating glutamate and tyrosine residues binds more tightly, which is consistent with the known importance of glutamylation for spastin microtubule severing activity. A cryo-EM structure of the spastin-peptide complex at 4.2 Å resolution revealed an asymmetric hexamer in which five spastin subunits adopt a helical, spiral staircase configuration that binds the peptide within the central pore, whereas the sixth subunit of the hexamer is displaced from the peptide/substrate, as if transitioning from one end of the helix to the other. This configuration differs from a recently published structure of spastin from Drosophila melanogaster, which forms a six-subunit spiral without a transitioning subunit. Our structure resembles other recently reported AAA unfoldases, including the meiotic clade relative Vps4, and supports a model in which spastin utilizes a hand-over-hand mechanism of tubulin translocation and microtubule remodeling.
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Affiliation(s)
- Han Han
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112
| | - Heidi L Schubert
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112
| | - John McCullough
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112
| | - Nicole Monroe
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112
| | - Michael D Purdy
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia 22908
| | - Mark Yeager
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia 22908; Department of Medicine, Division of Cardiovascular Medicine, University of Virginia School of Medicine, Charlottesville, Virginia 22908; Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, Virginia 22908; Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia 22908
| | - Wesley I Sundquist
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112.
| | - Christopher P Hill
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112.
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Fowler PC, Garcia-Pardo ME, Simpson JC, O'Sullivan NC. NeurodegenERation: The Central Role for ER Contacts in Neuronal Function and Axonopathy, Lessons From Hereditary Spastic Paraplegias and Related Diseases. Front Neurosci 2019; 13:1051. [PMID: 31680803 PMCID: PMC6801308 DOI: 10.3389/fnins.2019.01051] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/19/2019] [Indexed: 12/17/2022] Open
Abstract
The hereditary spastic paraplegias (HSPs) are a group of inherited neurodegenerative conditions whose characteristic feature is degeneration of the longest axons within the corticospinal tract which leads to progressive spasticity and weakness of the lower limbs. Though highly genetically heterogeneous, the majority of HSP cases are caused by mutations in genes encoding proteins that are responsible for generating and organizing the tubular endoplasmic reticulum (ER). Despite this, the role of the ER within neurons, particularly the long axons affected in HSP, is not well understood. Throughout axons, ER tubules make extensive contacts with other organelles, the cytoskeleton and the plasma membrane. At these ER contacts, protein complexes work in concert to perform specialized functions including organelle shaping, calcium homeostasis and lipid biogenesis, all of which are vital for neuronal survival and may be disrupted by HSP-causing mutations. In this article we summarize the proteins which mediate ER contacts, review the functions these contacts are known to carry out within neurons, and discuss the potential contribution of disruption of ER contacts to axonopathy in HSP.
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Affiliation(s)
- Philippa C Fowler
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - M Elena Garcia-Pardo
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Jeremy C Simpson
- UCD School of Biology and Environmental Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Niamh C O'Sullivan
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
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Guo W, Stoklund Dittlau K, Van Den Bosch L. Axonal transport defects and neurodegeneration: Molecular mechanisms and therapeutic implications. Semin Cell Dev Biol 2019; 99:133-150. [PMID: 31542222 DOI: 10.1016/j.semcdb.2019.07.010] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 06/22/2019] [Accepted: 07/09/2019] [Indexed: 12/12/2022]
Abstract
Because of the extremely polarized morphology, the proper functioning of neurons largely relies on the efficient cargo transport along the axon. Axonal transport defects have been reported in multiple neurodegenerative diseases as an early pathological feature. The discovery of mutations in human genes involved in the transport machinery provide a direct causative relationship between axonal transport defects and neurodegeneration. Here, we summarize the current genetic findings related to axonal transport in neurodegenerative diseases, and we discuss the relationship between axonal transport defects and other pathological changes observed in neurodegeneration. In addition, we summarize the therapeutic approaches targeting the axonal transport machinery in studies of neurodegenerative diseases. Finally, we review the technical advances in tracking axonal transport both in vivo and in vitro.
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Affiliation(s)
- Wenting Guo
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium; KU Leuven-Stem Cell Institute (SCIL), Leuven, Belgium
| | - Katarina Stoklund Dittlau
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Ludo Van Den Bosch
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.
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11
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Qiang L, Piermarini E, Baas PW. New hypothesis for the etiology of SPAST-based hereditary spastic paraplegia. Cytoskeleton (Hoboken) 2019; 76:289-297. [PMID: 31108029 DOI: 10.1002/cm.21528] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 01/26/2023]
Abstract
Mutations of the SPAST gene are the chief cause of hereditary spastic paraplegia. Controversy exists in the medical community as to whether the etiology of the disease is haploinsufficiency or toxic gain-of-function properties of the mutant spastin proteins. In recognition of strong reasons that support each possible mechanism, here we present a novel perspective, based in part on new studies with mouse models and in part on the largest study to date on patients with the disease. We posit that haploinsufficiency does not cause the disease but makes the corticospinal tracts vulnerable to a second hit, which is usually the mutant spastin proteins but could also be proteins generated by mutations of other genes that may or may not cause the disease on their own.
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Affiliation(s)
- Liang Qiang
- Department of Neurobiology and Anatomy, Drexel University, College of Medicine, Philadelphia, Pennsylvania
| | - Emanuela Piermarini
- Department of Neurobiology and Anatomy, Drexel University, College of Medicine, Philadelphia, Pennsylvania
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University, College of Medicine, Philadelphia, Pennsylvania
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12
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Shi Q, Lin YQ, Saliba A, Xie J, Neely GG, Banerjee S. Tubulin Polymerization Promoting Protein, Ringmaker, and MAP1B Homolog Futsch Coordinate Microtubule Organization and Synaptic Growth. Front Cell Neurosci 2019; 13:192. [PMID: 31156389 PMCID: PMC6529516 DOI: 10.3389/fncel.2019.00192] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 04/16/2019] [Indexed: 12/15/2022] Open
Abstract
Drosophila Ringmaker (Ringer) is homologous to the human Tubulin Polymerization Promoting Proteins (TPPPs) that are implicated in the stabilization and bundling of microtubules (MTs) that are particularly important for neurons and are also implicated in synaptic organization and plasticity. No in vivo functional data exist that have addressed the role of TPPP in synapse organization in any system. Here, we present the phenotypic and functional characterization of ringer mutants during Drosophila larval neuromuscular junction (NMJ) synaptic development. ringer mutants show reduced synaptic growth and transmission and display phenotypic similarities and genetic interactions with the Drosophila homolog of vertebrate Microtubule Associated Protein (MAP)1B, futsch. Immunohistochemical and biochemical analyses show that individual and combined loss of Ringer and Futsch cause a significant reduction in MT loops at the NMJs and reduced acetylated-tubulin levels. Presynaptic over-expression of Ringer and Futsch causes elevated levels of acetylated-tubulin and significant increase in NMJ MT loops. These results indicate that Ringer and Futsch regulate synaptic MT organization in addition to synaptic growth. Together our findings may inform studies on the close mammalian homolog, TPPP, and provide insights into the role of MTs and associated proteins in synapse growth and organization.
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Affiliation(s)
- Qian Shi
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health, San Antonio, TX, United States
| | - Yong Qi Lin
- The Dr. John and Anne Chong Lab for Functional Genomics, Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Afaf Saliba
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health, San Antonio, TX, United States
| | - Jing Xie
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health, San Antonio, TX, United States
- Xiangya School of Medicine, Central South University, Changsha, China
| | - G. Gregory Neely
- The Dr. John and Anne Chong Lab for Functional Genomics, Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Swati Banerjee
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health, San Antonio, TX, United States
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The function of histone acetylation in cervical cancer development. Biosci Rep 2019; 39:BSR20190527. [PMID: 30886064 PMCID: PMC6465204 DOI: 10.1042/bsr20190527] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 03/14/2019] [Accepted: 03/15/2019] [Indexed: 12/19/2022] Open
Abstract
Cervical cancer is the fourth most common female cancer in the world. It is well known that cervical cancer is closely related to high-risk human papillomavirus (HPV) infection. However, epigenetics has increasingly been recognized for its role in tumorigenesis. Epigenetics refers to changes in gene expression levels based on non-gene sequence changes, primarily through transcription or translation of genes regulation, thus affecting its function and characteristics. Typical post-translational modifications (PTMs) include acetylation, propionylation, butyrylation, malonylation and succinylation, among which the acetylation modification of lysine sites has been studied more clearly so far. The acetylation modification of lysine residues in proteins is involved in many aspects of cellular life activities, including carbon metabolism, transcriptional regulation, amino acid metabolism and so on. In this review, we summarize the latest discoveries on cervical cancer development arising from the aspect of acetylation, especially histone acetylation.
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