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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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Yu W, Jin H, Deng J, Nan D, Huang Y. A novel SPAST gene mutation identified in a Chinese family with hereditary spastic paraplegia. BMC MEDICAL GENETICS 2020; 21:123. [PMID: 32493220 PMCID: PMC7268315 DOI: 10.1186/s12881-020-01053-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 05/19/2020] [Indexed: 11/19/2022]
Abstract
Background Hereditary spastic paraplegia is a heterogeneous group of clinically and genetically neurodegenerative diseases characterized by progressive gait disorder. Hereditary spastic paraplegia can be inherited in various ways, and all modes of inheritance are associated with multiple genes or loci. At present, more than 76 disease-causing loci have been identified in hereditary spastic paraplegia patients. Here, we report a novel mutation in SPAST gene associated with hereditary spastic paraplegia in a Chinese family, further enriching the hereditary spastic paraplegia spectrum. Methods Whole genomic DNA was extracted from peripheral blood of the 15 subjects from a Chinese family using DNA Isolation Kit. The Whole Exome Sequencing of the proband was analyzed and the result was identified in the rest individuals. RaptorX prediction tool and Protein Variation Effect Analyzer were used to predict the effects of the mutation on protein tertiary structure and function. Results Spastic paraplegia has been inherited across at least four generations in this family, during which only four HSP patients were alive. The results obtained by analyzing the Whole Exome Sequencing of the proband exhibited a novel disease-associated in-frame deletion in the SPAST gene, and this mutation also existed in the rest three HSP patients in this family. This in-frame deletion consists of three nucleotides deletion (c.1710_1712delGAA) within the exon 16, resulting in lysine deficiency at the position 570 of the protein (p.K570del). This novel mutation was also predicted to result in the synthesis of misfolded SPAST protein and have the deleterious effect on the function of SPAST protein. Conclusion In this case, we reported a novel mutation in the known SPAST gene that segregated with HSP disease, which can be inherited in each generation. Simultaneously, this novel discovery significantly enriches the mutation spectrum, which provides an opportunity for further investigation of genetic pathogenesis of HSP.
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Affiliation(s)
- Weiwei Yu
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street Xicheng District, Beijing, 100034, China
| | - Haiqiang Jin
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street Xicheng District, Beijing, 100034, China
| | - Jianwen Deng
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street Xicheng District, Beijing, 100034, China
| | - Ding Nan
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street Xicheng District, Beijing, 100034, China
| | - Yining Huang
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street Xicheng District, Beijing, 100034, China.
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Plaud C, Joshi V, Kajevu N, Poüs C, Curmi PA, Burgo A. Functional differences of short and long isoforms of spastin harboring missense mutation. Dis Model Mech 2018; 11:11/9/dmm033704. [PMID: 30213879 PMCID: PMC6177001 DOI: 10.1242/dmm.033704] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 07/03/2018] [Indexed: 01/05/2023] Open
Abstract
Mutations of the SPG4 (SPAST) gene encoding for spastin protein are the main causes of hereditary spastic paraplegia. Spastin binds to microtubules and severs them through the enzymatic activity of its AAA domain. Several missense mutations located in this domain lead to stable, nonsevering spastins that decorate a subset of microtubules, suggesting a possible negative gain-of-function mechanism for these mutants. Of the two main isoforms of spastin, only mutations of the long isoform, M1, are supposed to be involved in the onset of the pathology, leaving the role of the ubiquitously expressed shorter one, M87, not fully investigated and understood. Here, we show that two isoforms of spastin harboring the same missense mutation bind and bundle different subsets of microtubules in HeLa cells, and likely stabilize them by increasing the level of acetylated tubulin. However, only mutated M1 has the ability to interact with wild-type M1, and decorates a subset of perinuclear microtubules associated with the endoplasmic reticulum that display higher resistance to microtubule depolymerization and increased intracellular ionic strength, compared with those decorated by mutated M87. We further show that only mutated M1 decorates microtubules of proximal axons and dendrites, and strongly impairs axonal transport in cortical neurons through a mechanism likely independent of the microtubule-severing activity of this protein. Summary: Long and short isoforms of spastin (SPG4) harboring the same missense mutation show different intracellular localization, resistance to pharmacological treatments and effects on axonal cargo transport.
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Affiliation(s)
- Clément Plaud
- Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris Saclay, Université d'Evry, 91000 Evry, France
| | - Vandana Joshi
- Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris Saclay, Université d'Evry, 91000 Evry, France
| | - Natallie Kajevu
- Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris Saclay, Université d'Evry, 91000 Evry, France
| | - Christian Poüs
- INSERM UMR-S 1193, Faculty of Pharmacy, Univirsité Paris-Sud, Université Paris-Saclay, 92296 Châtenay-Malabry, France
| | - Patrick A Curmi
- Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris Saclay, Université d'Evry, 91000 Evry, France
| | - Andrea Burgo
- Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris Saclay, Université d'Evry, 91000 Evry, France
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Cooper HM, Yang Y, Ylikallio E, Khairullin R, Woldegebriel R, Lin KL, Euro L, Palin E, Wolf A, Trokovic R, Isohanni P, Kaakkola S, Auranen M, Lönnqvist T, Wanrooij S, Tyynismaa H. ATPase-deficient mitochondrial inner membrane protein ATAD3A disturbs mitochondrial dynamics in dominant hereditary spastic paraplegia. Hum Mol Genet 2017; 26:1432-1443. [PMID: 28158749 PMCID: PMC5393146 DOI: 10.1093/hmg/ddx042] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 01/24/2017] [Indexed: 01/02/2023] Open
Abstract
De novo mutations in ATAD3A (ATPase family AAA-domain containing protein 3A) were recently found to cause a neurological syndrome with developmental delay, hypotonia, spasticity, optic atrophy, axonal neuropathy, and hypertrophic cardiomyopathy. Using whole-exome sequencing, we identified a dominantly inherited heterozygous variant c.1064G > A (p.G355D) in ATAD3A in a mother presenting with hereditary spastic paraplegia (HSP) and axonal neuropathy and her son with dyskinetic cerebral palsy, both with disease onset in childhood. HSP is a clinically and genetically heterogeneous disorder of the upper motor neurons. Symptoms beginning in early childhood may resemble spastic cerebral palsy. The function of ATAD3A, a mitochondrial inner membrane AAA ATPase, is yet undefined. AAA ATPases form hexameric rings, which are catalytically dependent on the co-operation of the subunits. The dominant-negative patient mutation affects the Walker A motif, which is responsible for ATP binding in the AAA module of ATAD3A, and we show that the recombinant mutant ATAD3A protein has a markedly reduced ATPase activity. We further show that overexpression of the mutant ATAD3A fragments the mitochondrial network and induces lysosome mass. Similarly, we observed altered dynamics of the mitochondrial network and increased lysosomes in patient fibroblasts and neurons derived through differentiation of patient-specific induced pluripotent stem cells. These alterations were verified in patient fibroblasts to associate with upregulated basal autophagy through mTOR inactivation, resembling starvation. Mutations in ATAD3A can thus be dominantly inherited and underlie variable neurological phenotypes, including HSP, with intrafamiliar variability. This finding extends the group of mitochondrial inner membrane AAA proteins associated with spasticity.
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Affiliation(s)
- Helen M Cooper
- Åbo Akademi University, Faculty of Natural Sciences and Technology, Turku, Finland
| | - Yang Yang
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.,Institute of Neuroscience, Zhejiang University School of Medicine, Hangzhou, P.R. China
| | - Emil Ylikallio
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.,Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Rafil Khairullin
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden.,Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Kazan, Russia
| | - Rosa Woldegebriel
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Kai-Lan Lin
- Åbo Akademi University, Faculty of Natural Sciences and Technology, Turku, Finland
| | - Liliya Euro
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Eino Palin
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Alexander Wolf
- Institute of Molecular Toxicology and Pharmacology, Helmholtz-Zentrum Muenchen-German Research Center for Environmental Health, Neuherberg, Germany
| | - Ras Trokovic
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Pirjo Isohanni
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.,Department of Child Neurology, Children's Hospital, Helsinki University Hospital, Helsinki, Finland
| | - Seppo Kaakkola
- Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Mari Auranen
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.,Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Tuula Lönnqvist
- Department of Child Neurology, Children's Hospital, Helsinki University Hospital, Helsinki, Finland
| | - Sjoerd Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Henna Tyynismaa
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.,Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland
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Bailey ME, Sackett DL, Ross JL. Katanin Severing and Binding Microtubules Are Inhibited by Tubulin Carboxy Tails. Biophys J 2016; 109:2546-2561. [PMID: 26682813 DOI: 10.1016/j.bpj.2015.11.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 10/30/2015] [Accepted: 11/04/2015] [Indexed: 10/22/2022] Open
Abstract
Microtubule dynamics in cells are regulated by associated proteins that can be either stabilizers or destabilizers. A class of destabilizers that is important in a large number of cellular activities is the microtubule-severing enzymes, yet little is known about how they function. Katanin p60 was the first ATPase associated with microtubule severing. Here, we investigate the activity of katanin severing using a GFP-labeled human version. We quantify the effect of katanin concentration on katanin binding and severing activity. We find that free tubulin can inhibit severing activity by interfering with katanin binding to microtubules. The inhibition is mediated by the sequence of the tubulin and specifically depends on the carboxy-terminal tails. We directly investigate the inhibition effect of tubulin carboxy-terminal tails using peptide sequences of α-, β-, or detyrosinated α-tubulin tails that have been covalently linked to bovine serum albumin. Our results show that β-tubulin tails are the most effective at inhibiting severing, and that detyrosinated α-tubulin tails are the least effective. These results are distinct from those for other severing enzymes and suggest a scheme for regulation of katanin activity in cells dependent on free tubulin concentration and the modification state of the tubulin.
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Affiliation(s)
- Megan E Bailey
- Molecular and Cellular Biology Graduate Program, University of Massachusetts-Amherst, Amherst, Massachusetts; Department of Physics, University of Massachusetts-Amherst, Amherst, Massachusetts
| | - Dan L Sackett
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Jennifer L Ross
- Department of Physics, University of Massachusetts-Amherst, Amherst, Massachusetts.
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Zeymer C, Fischer S, Reinstein J. trans-Acting arginine residues in the AAA+ chaperone ClpB allosterically regulate the activity through inter- and intradomain communication. J Biol Chem 2014; 289:32965-76. [PMID: 25253689 PMCID: PMC4239642 DOI: 10.1074/jbc.m114.608828] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The molecular chaperone ClpB/Hsp104, a member of the AAA+ superfamily (ATPases associated with various cellular activities), rescues proteins from the aggregated state in collaboration with the DnaK/Hsp70 chaperone system. ClpB/Hsp104 forms a hexameric, ring-shaped complex that functions as a tightly regulated, ATP-powered molecular disaggregation machine. Highly conserved and essential arginine residues, often called arginine fingers, are located at the subunit interfaces of the complex, which also harbor the catalytic sites. Several AAA+ proteins, including ClpB/Hsp104, possess a pair of such trans-acting arginines in the N-terminal nucleotide binding domain (NBD1), both of which were shown to be crucial for oligomerization and ATPase activity. Here, we present a mechanistic study elucidating the role of this conserved arginine pair. First, we found that the arginines couple nucleotide binding to oligomerization of NBD1, which is essential for the activity. Next, we designed a set of covalently linked, dimeric ClpB NBD1 variants, carrying single subunits deficient in either ATP binding or hydrolysis, to study allosteric regulation and intersubunit communication. Using this well defined environment of site-specifically modified, cross-linked AAA+ domains, we found that the conserved arginine pair mediates the cooperativity of ATP binding and hydrolysis in an allosteric fashion.
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Affiliation(s)
- Cathleen Zeymer
- From the Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Sebastian Fischer
- From the Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Jochen Reinstein
- From the Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
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