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Gao H, Chen Z, Zhao L, Ji C, Xing F. Cellular functions, molecular signalings and therapeutic applications: Translational potential of deubiquitylating enzyme USP9X as a drug target in cancer treatment. Biochim Biophys Acta Rev Cancer 2024; 1879:189099. [PMID: 38582329 DOI: 10.1016/j.bbcan.2024.189099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/13/2023] [Accepted: 03/31/2024] [Indexed: 04/08/2024]
Abstract
Protein ubiquitination, one of the most significant post-translational modifications, plays an important role in controlling the proteins activity in diverse cellular processes. The reversible process of protein ubiquitination, known as deubiquitination, has emerged as a critical mechanism for maintaining cellular homeostasis. The deubiquitinases (DUBs), which participate in deubiquitination process are increasingly recognized as potential candidates for drug discovery. Among these DUBs, ubiquitin-specific protease 9× (USP9X), a highly conserved member of the USP family, exhibits versatile functions in various cellular processes, including the regulation of cell cycle, protein endocytosis, apoptosis, cell polarity, immunological microenvironment, and stem cell characteristics. The dysregulation and abnormal activities of USP9X are influenced by intricate cellular signaling pathway crosstalk and upstream non-coding RNAs. The complex expression patterns and controversial clinical significance of USP9X in cancers suggest its potential as a prognostic biomarker. Furthermore, USP9X inhibitors has shown promising antitumor activity and holds the potential to overcome therapeutic resistance in preclinical models. However, a comprehensive summary of the role and molecular functions of USP9X in cancer progression is currently lacking. In this review, we provide a comprehensive delineation of USP9X participation in numerous critical cellular processes, complicated signaling pathways within the tumor microenvironment, and its potential translational applications to combat therapeutic resistance. By systematically summarizing the updated molecular mechanisms of USP9X in cancer biology, this review aims to contribute to the advancement of cancer therapeutics and provide essential insights for specialists and clinicians in the development of improved cancer treatment strategies.
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Affiliation(s)
- Hongli Gao
- Department of Oncology, Shengjing Hospital of China Medical University, Shenyang 110004, China
| | - Zhiguang Chen
- Department of Emergency Medicine, Shengjing Hospital of China Medical University, Shenyang 110004, China
| | - Liang Zhao
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang 110004, China
| | - Ce Ji
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang 110004, China.
| | - Fei Xing
- Department of Oncology, Shengjing Hospital of China Medical University, Shenyang 110004, China.
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2
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Saha S, Huang SYN, Yang X, Saha LK, Sun Y, Khandagale P, Jenkins LM, Pommier Y. The TDRD3-USP9X complex and MIB1 regulate TOP3B homeostasis and prevent deleterious TOP3B cleavage complexes. Nat Commun 2023; 14:7524. [PMID: 37980342 PMCID: PMC10657456 DOI: 10.1038/s41467-023-43151-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 11/01/2023] [Indexed: 11/20/2023] Open
Abstract
TOP3B is stabilized by TDRD3. Hypothesizing that TDRD3 recruits a deubiquitinase, we find that TOP3B interacts with USP9X via TDRD3. Inactivation of USP9X destabilizes TOP3B, and depletion of both TDRD3 and USP9X does not promote further TOP3B ubiquitylation. Additionally, we observe that MIB1 mediates the ubiquitylation and proteasomal degradation of TOP3B by directly interacting with TOP3B independently of TDRD3. Combined depletion of USP9X, TDRD3 and MIB1 causes no additional increase in TOP3B levels compared to MIB1 knockdown alone indicating that the TDRD3-USP9X complex works downstream of MIB1. To comprehend why cells degrade TOP3B in the absence of TDRD3, we measured TOP3Bccs. Lack of TDRD3 increases TOP3Bccs in DNA and RNA, and induced R-loops, γH2AX and growth defect. Biochemical experiments confirm that TDRD3 increases the turnover of TOP3B. Our work provides molecular insights into the mechanisms by which TDRD3 protect cells from deleterious TOP3Bccs which are otherwise removed by TRIM41.
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Affiliation(s)
- Sourav Saha
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Shar-Yin Naomi Huang
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Xi Yang
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Liton Kumar Saha
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Yilun Sun
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Prashant Khandagale
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Lisa M Jenkins
- Collaborative Protein Technology Resource, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Yves Pommier
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA.
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Mohammadi MA, Mansouri M, Derakhshani A, Rezaie M, Borhani M, Nasibi S, Mousavi SM, Afgar A, Macchiaroli N, Rosenzvit MC, Harandi MF. MicroRNA-Transcription factor regulatory networks in the early strobilar development of Echinococcus granulosus protoscoleces. BMC Genomics 2023; 24:114. [PMID: 36922762 PMCID: PMC10016175 DOI: 10.1186/s12864-023-09199-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 02/21/2023] [Indexed: 03/17/2023] Open
Abstract
BACKGROUND Echinococcus granulosus sensu lato has a complex developmental biology with a variety of factors relating to both intermediate and final hosts. To achieve maximum parasite adaptability, the development of the cestode is dependent on essential changes in transcript regulation. Transcription factors (TFs) and miRNAs are known as master regulators that affect the expression of downstream genes through a wide range of metabolic and signaling pathways. In this study, we aimed to develop a regulatory miRNA-Transcription factor (miRNA-TF) network across early developmental stages of E. granulosus protoscoleces by performing in silico analysis, and to experimentally validate TFs expression in protoscoleces obtained from in vitro culture, and from in vivo experiments. RESULTS We obtained list of 394 unique E. granulosus TFs and matched them with 818 differentially expressed genes which identified 41 predicted TFs with differential expression. These TFs were used to predict the potential targets of 31 differentially expressed miRNAs. As a result, eight miRNAs and eight TFs were found, and the predicted network was constructed using Cytoscape. At least four miRNAs (egr-miR-124a, egr-miR-124b-3p, egr-miR-745-3p, and egr-miR-87-3p) and their corresponding differentially expressed TFs (Zinc finger protein 45, Early growth response protein 3, Ecdysone induced protein 78c and ETS transcription factor elf 2) were highlighted in this investigation. The expression of predicted differentially expressed TFs obtained from in vitro and in vivo experiments, were experimentally validated by quantitative polymerase chain reaction. This confirmed findings of RNA-seq data. CONCLUSION miRNA-TF networks presented in this study control some of the most important metabolic and signaling pathways in the development and life cycle of E. granulosus, providing a potential approach for disrupting the early hours of dog infection and preventing the development of the helminth in the final host.
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Affiliation(s)
- Mohammad Ali Mohammadi
- Research Center for Hydatid Disease in Iran, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Mehdi Mansouri
- Department of Agricultural Biotechnology, Faculty of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Ali Derakhshani
- Research Center for Hydatid Disease in Iran, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Masoud Rezaie
- Student Research Committee, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Mehdi Borhani
- State Key Laboratory for Zoonotic Diseases, Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Jilin, China
| | - Saeid Nasibi
- Research Center for Hydatid Disease in Iran, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Seyed Mohammad Mousavi
- Research Center for Hydatid Disease in Iran, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Ali Afgar
- Research Center for Hydatid Disease in Iran, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Natalia Macchiaroli
- Laboratorio Biología Molecular de Hidatidosis, Facultad de Medicina, Instituto de Microbiología Y Parasitología Médica (IMPaM), Consejo Nacional de Investigaciones Científicas Y Tecnológicas (CONICET), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Mara C. Rosenzvit
- Laboratorio Biología Molecular de Hidatidosis, Facultad de Medicina, Instituto de Microbiología Y Parasitología Médica (IMPaM), Consejo Nacional de Investigaciones Científicas Y Tecnológicas (CONICET), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Majid Fasihi Harandi
- Research Center for Hydatid Disease in Iran, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
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Riboldi GM, Faravelli I, Rinchetti P, Lotti F. SMN post-translational modifications in spinal muscular atrophy. Front Cell Neurosci 2023; 17:1092488. [PMID: 36874214 PMCID: PMC9981653 DOI: 10.3389/fncel.2023.1092488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/26/2023] [Indexed: 02/19/2023] Open
Abstract
Since its first identification as the gene responsible for spinal muscular atrophy (SMA), the range of survival motor neuron (SMN) protein functions has increasingly expanded. This multimeric complex plays a crucial role in a variety of RNA processing pathways. While its most characterized function is in the biogenesis of ribonucleoproteins, several studies have highlighted the SMN complex as an important contributor to mRNA trafficking and translation, axonal transport, endocytosis, and mitochondria metabolism. All these multiple functions need to be selectively and finely modulated to maintain cellular homeostasis. SMN has distinct functional domains that play a crucial role in complex stability, function, and subcellular distribution. Many different processes were reported as modulators of the SMN complex activities, although their contribution to SMN biology still needs to be elucidated. Recent evidence has identified post-translational modifications (PTMs) as a way to regulate the pleiotropic functions of the SMN complex. These modifications include phosphorylation, methylation, ubiquitination, acetylation, sumoylation, and many other types. PTMs can broaden the range of protein functions by binding chemical moieties to specific amino acids, thus modulating several cellular processes. Here, we provide an overview of the main PTMs involved in the regulation of the SMN complex with a major focus on the functions that have been linked to SMA pathogenesis.
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Affiliation(s)
| | | | | | - Francesco Lotti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY, United States
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Detering NT, Schüning T, Hensel N, Claus P. The phospho-landscape of the survival of motoneuron protein (SMN) protein: relevance for spinal muscular atrophy (SMA). Cell Mol Life Sci 2022; 79:497. [PMID: 36006469 PMCID: PMC11071818 DOI: 10.1007/s00018-022-04522-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 07/27/2022] [Accepted: 08/09/2022] [Indexed: 11/03/2022]
Abstract
Spinal muscular atrophy (SMA) is caused by low levels of the survival of motoneuron (SMN) Protein leading to preferential degeneration of lower motoneurons in the ventral horn of the spinal cord and brain stem. However, the SMN protein is ubiquitously expressed and there is growing evidence of a multisystem phenotype in SMA. Since a loss of SMN function is critical, it is important to decipher the regulatory mechanisms of SMN function starting on the level of the SMN protein itself. Posttranslational modifications (PTMs) of proteins regulate multiple functions and processes, including activity, cellular trafficking, and stability. Several PTM sites have been identified within the SMN sequence. Here, we map the identified SMN PTMs highlighting phosphorylation as a key regulator affecting localization, stability and functions of SMN. Furthermore, we propose SMN phosphorylation as a crucial factor for intracellular interaction and cellular distribution of SMN. We outline the relevance of phosphorylation of the spinal muscular atrophy (SMA) gene product SMN with regard to basic housekeeping functions of SMN impaired in this neurodegenerative disease. Finally, we compare SMA patient mutations with putative and verified phosphorylation sites. Thus, we emphasize the importance of phosphorylation as a cellular modulator in a clinical perspective as a potential additional target for combinatorial SMA treatment strategies.
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Affiliation(s)
- Nora Tula Detering
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Tobias Schüning
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Niko Hensel
- Ottawa Hospital Research Institute (OHRI), Ottawa, Canada
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Peter Claus
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany.
- Center for Systems Neuroscience (ZSN), Hannover, Germany.
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Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disorder caused by mutations in SMN1 (encoding survival motor neuron protein (SMN)). Reduced expression of SMN leads to loss of α-motor neurons, severe muscle weakness and often early death. Standard-of-care recommendations for multidisciplinary supportive care of SMA were established in the past few decades. However, improved understanding of the pathogenetic mechanisms of SMA has led to the development of different therapeutic approaches. Three treatments that increase SMN expression by distinct molecular mechanisms, administration routes and tissue biodistributions have received regulatory approval with others in clinical development. The advent of the new therapies is redefining standards of care as in many countries most patients are treated with one of the new therapies, leading to the identification of emerging new phenotypes of SMA and a renewed characterization of demographics owing to improved patient survival.
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Kim JH, Kang JS, Yoo K, Jeong J, Park I, Park JH, Rhee J, Jeon S, Jo YW, Hann SH, Seo M, Moon S, Um SJ, Seong RH, Kong YY. Bap1/SMN axis in Dpp4+ skeletal muscle mesenchymal cells regulates the neuromuscular system. JCI Insight 2022; 7:158380. [PMID: 35603786 PMCID: PMC9220848 DOI: 10.1172/jci.insight.158380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/06/2022] [Indexed: 12/15/2022] Open
Abstract
The survival of motor neuron (SMN) protein is a major component of the pre-mRNA splicing machinery and is required for RNA metabolism. Although SMN has been considered a fundamental gene for the central nervous system, due to its relationship with neuromuscular diseases, such as spinal muscular atrophy, recent studies have also revealed the requirement of SMN in non-neuronal cells in the peripheral regions. Here, we report that the fibro-adipogenic progenitor subpopulation expressing Dpp4 (Dpp4+ FAPs) is required for the neuromuscular system. Furthermore, we also reveal that BRCA1-associated protein-1 (Bap1) is crucial for the stabilization of SMN in FAPs by preventing its ubiquitination-dependent degradation. Inactivation of Bap1 in FAPs decreased SMN levels and accompanied degeneration of the neuromuscular junction, leading to loss of motor neurons and muscle atrophy. Overexpression of the ubiquitination-resistant SMN variant, SMNK186R, in Bap1-null FAPs completely prevented neuromuscular degeneration. In addition, transplantation of Dpp4+ FAPs, but not Dpp4– FAPs, completely rescued neuromuscular defects. Our data reveal the crucial role of Bap1-mediated SMN stabilization in Dpp4+ FAPs for the neuromuscular system and provide the possibility of cell-based therapeutics to treat neuromuscular diseases.
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Affiliation(s)
- Ji-Hoon Kim
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Molecular Recognition Research Center, Korea Institute of Science and Technology, Seoul, South Korea
| | - Jong-Seol Kang
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Kyusang Yoo
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Jinguk Jeong
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Inkuk Park
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Jong Ho Park
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Joonwoo Rhee
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Shin Jeon
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Young-Woo Jo
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Sang-Hyeon Hann
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Minji Seo
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Seungtae Moon
- Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul, South Korea
| | - Soo-Jong Um
- Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul, South Korea
| | - Rho Hyun Seong
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Young-Yun Kong
- School of Biological Sciences, Seoul National University, Seoul, South Korea
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Dumas SA, Villalón E, Bergman EM, Wilson KJ, Marugan JJ, Lorson CL, Burnett BG. OUP accepted manuscript. Hum Mol Genet 2022; 31:2989-3000. [PMID: 35419606 PMCID: PMC9433732 DOI: 10.1093/hmg/ddac068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/01/2022] [Accepted: 03/18/2022] [Indexed: 11/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by reduced expression of the survival motor neuron (SMN) protein. Current disease-modifying therapies increase SMN levels and dramatically improve survival and motor function of SMA patients. Nevertheless, current treatments are not cures and autopsy data suggest that SMN induction is variable. Our group and others have shown that combinatorial approaches that target different modalities can improve outcomes in rodent models of SMA. Here we explore if slowing SMN protein degradation and correcting SMN splicing defects could synergistically increase SMN production and improve the SMA phenotype in model mice. We show that co-administering ML372, which inhibits SMN ubiquitination, with an SMN-modifying antisense oligonucleotide (ASO) increases SMN production in SMA cells and model mice. In addition, we observed improved spinal cord, neuromuscular junction and muscle pathology when ML372 and the ASO were administered in combination. Importantly, the combinatorial approach resulted in increased motor function and extended survival of SMA mice. Our results demonstrate that a combination of treatment modalities synergistically increases SMN levels and improves pathophysiology of SMA model mice over individual treatment.
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Affiliation(s)
| | | | - Elizabeth M Bergman
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, F. Edward Herbert School of Medicine, Bethesda, MD 20814, USA
| | - Kenneth J Wilson
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20892-2152, USA
| | - Juan J Marugan
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20892-2152, USA
| | - Christian L Lorson
- To whom correspondence should be addressed at: Barrington G. Burnett. Tel: +1 301-295-3506; ; Christian L. Lorson. Tel: +1 573-884-2219;
| | - Barrington G Burnett
- To whom correspondence should be addressed at: Barrington G. Burnett. Tel: +1 301-295-3506; ; Christian L. Lorson. Tel: +1 573-884-2219;
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9
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Soler L, Alves S, Brionne A, Jacques A, Guérin V, Cherif-Feildel M, Combes-Soia L, Fouchécourt S, Thélie A, Blesbois E, McGrew MJ, Labas V, Govoroun MS. Protein expression reveals a molecular sexual identity of avian primordial germ cells at pre-gonadal stages. Sci Rep 2021; 11:19236. [PMID: 34584135 DOI: 10.1038/s41598-021-98454-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 09/06/2021] [Indexed: 11/11/2022] Open
Abstract
In poultry, in vitro propagated primordial germ cells (PGCs) represent an important tool for the cryopreservation of avian genetic resources. However, several studies have highlighted sexual differences exhibited by PGCs during in vitro propagation, which may compromise their reproductive capacities. To understand this phenomenon, we compared the proteome of pregonadal migratory male (ZZ) and female (ZW) chicken PGCs propagated in vitro by quantitative proteomic analysis using a GeLC-MS/MS strategy. Many proteins were found to be differentially abundant in chicken male and female PGCs indicating their early sexual identity. Many of the proteins more highly expressed in male PGCs were encoded by genes localised to the Z sex chromosome. This suggests that the known lack of dosage compensation of the transcription of Z-linked genes between sexes persists at the protein level in PGCs, and that this may be a key factor of their autonomous sex differentiation. We also found that globally, protein differences do not closely correlate with transcript differences indicating a selective translational mechanism in PGCs. Male and female PGC expressed protein sets were associated with differential biological processes and contained proteins known to be biologically relevant for male and female germ cell development, respectively. We also discovered that female PGCs have a higher capacity to uptake proteins from the cell culture medium than male PGCs. This study presents the first evidence of an early predetermined sex specific cell fate of chicken PGCs and their sexual molecular specificities which will enable the development of more precise sex-specific in vitro culture conditions for the preservation of avian genetic resources.
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McCormack NM, Abera MB, Arnold ES, Gibbs RM, Martin SE, Buehler E, Chen YC, Chen L, Fischbeck KH, Burnett BG. A high-throughput genome-wide RNAi screen identifies modifiers of survival motor neuron protein. Cell Rep 2021; 35:109125. [PMID: 33979606 PMCID: PMC8679797 DOI: 10.1016/j.celrep.2021.109125] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 03/17/2021] [Accepted: 04/22/2021] [Indexed: 11/28/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a debilitating neurological disorder marked by degeneration of spinal motor neurons and muscle atrophy. SMA results from mutations in survival motor neuron 1 (SMN1), leading to deficiency of survival motor neuron (SMN) protein. Current therapies increase SMN protein and improve patient survival but have variable improvements in motor function, making it necessary to identify complementary strategies to further improve disease outcomes. Here, we perform a genome-wide RNAi screen using a luciferase-based activity reporter and identify genes involved in regulating SMN gene expression, RNA processing, and protein stability. We show that reduced expression of Transcription Export complex components increases SMN levels through the regulation of nuclear/cytoplasmic RNA transport. We also show that the E3 ligase, Neurl2, works cooperatively with Mib1 to ubiquitinate and promote SMN degradation. Together, our screen uncovers pathways through which SMN expression is regulated, potentially revealing additional strategies to treat SMA. Treatments for spinal muscular atrophy aim to increase survival motor neuron (SMN) protein. Using a genome-wide RNAi screen, McCormack et al. identify modifiers of SMN expression, including genes that are involved in transcription regulation, RNA processing, and protein stability.
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Affiliation(s)
- Nikki M McCormack
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA
| | - Mahlet B Abera
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA
| | - Eveline S Arnold
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Rebecca M Gibbs
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Scott E Martin
- Functional Genomics Lab, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20850, USA
| | - Eugen Buehler
- Functional Genomics Lab, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20850, USA
| | - Yu-Chi Chen
- Functional Genomics Lab, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20850, USA
| | - Lu Chen
- Functional Genomics Lab, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20850, USA
| | - Kenneth H Fischbeck
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Barrington G Burnett
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA.
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11
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Zhang B, Cheng X, Zhan S, Jin X, Liu T. MIB1 upregulates IQGAP1 and promotes pancreatic cancer progression by inducing ST7 degradation. Mol Oncol 2021; 15:3062-3075. [PMID: 33793053 PMCID: PMC8564634 DOI: 10.1002/1878-0261.12955] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 02/07/2021] [Accepted: 03/30/2021] [Indexed: 11/19/2022] Open
Abstract
Despite recent progress in cancer treatment, the prognosis of patients with pancreatic cancer still remains poor. Pancreatic tumors are reported to display high molecular heterogeneity. Elucidating the molecular mechanisms underlying pancreatic cancer progression is essential for improving patient treatment and survival. The overexpression of E3 ubiquitin ligase mind bomb 1 (MIB1) was previously described in pancreatic cancer cells, where it enhanced tumor cell proliferation. However, the role of MIB1 in pancreatic cancer progression remains elusive. In the present study, we confirmed that MIB1 expression is elevated in pancreatic cancer tissues and that high levels of MIB associate with unfavorable prognosis. Overexpression of MIB1 enhanced proliferation and invasion of pancreatic cancer cells both in vitro and in vivo. We further investigated the molecular mechanisms downstream of MIB1 and observed for the first time that MIB1 targets suppressor of tumorigenicity 7 protein (ST7), previously described as suppressor of tumorigenicity, for proteasomal degradation. Furthermore, we found that ST7 suppressed tumor growth by downregulating IQ motif containing GTPase activating protein 1 (IQGAP1) in pancreatic tumor cells. Thus, these data show that MIB1 promotes pancreatic cancer progression by inducing ST7 degradation followed by downregulation of IQGAP1 in pancreatic cancer cells. In conclusion, our research shows that the MIB1/ST7/IQGAP1 axis is essential for pancreatic cancer progression, and MIB1 inhibition may serve as a novel therapeutic strategy in patients with pancreatic cancer.
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Affiliation(s)
- Bin Zhang
- Department of Digestive Surgical Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiang Cheng
- Department of Digestive Surgical Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Sudong Zhan
- Department of Digestive Surgical Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xin Jin
- Department of Urology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Tao Liu
- Department of Digestive Surgical Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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12
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Winkelsas AM, Grunseich C, Harmison GG, Chwalenia K, Rinaldi C, Hammond SM, Johnson K, Bowerman M, Arya S, Talbot K, Wood MJ, Fischbeck KH. Targeting the 5' untranslated region of SMN2 as a therapeutic strategy for spinal muscular atrophy. Mol Ther Nucleic Acids 2021; 23:731-42. [PMID: 33575118 DOI: 10.1016/j.omtn.2020.12.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 12/30/2020] [Indexed: 11/21/2022]
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by mutations in the survival motor neuron 1 (SMN1) gene. All patients have at least one copy of a paralog, SMN2, but a C-to-T transition in this gene results in exon 7 skipping in a majority of transcripts. Approved treatment for SMA involves promoting exon 7 inclusion in the SMN2 transcript or increasing the amount of full-length SMN by gene replacement with a viral vector. Increasing the pool of SMN2 transcripts and increasing their translational efficiency can be used to enhance splice correction. We sought to determine whether the 5' untranslated region (5' UTR) of SMN2 contains a repressive feature that can be targeted to increase SMN levels. We found that antisense oligonucleotides (ASOs) complementary to the 5' end of SMN2 increase SMN mRNA and protein levels and that this effect is due to inhibition of SMN2 mRNA decay. Moreover, use of the 5' UTR ASO in combination with a splice-switching oligonucleotide (SSO) increases SMN levels above those attained with the SSO alone. Our results add to the current understanding of SMN regulation and point toward a new therapeutic target for SMA.
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13
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Dutta D, Sharma V, Mutsuddi M, Mukherjee A. Regulation of Notch signaling by E3 ubiquitin ligases. FEBS J 2021; 289:937-954. [PMID: 33644958 DOI: 10.1111/febs.15792] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 02/07/2021] [Accepted: 02/25/2021] [Indexed: 12/11/2022]
Abstract
Notch signaling is an evolutionarily conserved pathway that is widely used for multiple cellular events during development. Activation of the Notch pathway occurs when the ligand from a neighboring cell binds to the Notch receptor and induces cleavage of the intracellular domain of Notch, which further translocates into the nucleus to activate its downstream genes. The involvement of the Notch pathway in diverse biological events is possible due to the complexity in its regulation. In order to maintain tight spatiotemporal regulation, the Notch receptor, as well as its ligand, undergoes a series of physical and biochemical modifications that, in turn, helps in proper maintenance and fine-tuning of the signaling outcome. Ubiquitination is the post-translational addition of a ubiquitin molecule to a substrate protein, and the process is regulated by E3 ubiquitin ligases. The present review describes the involvement of different E3 ubiquitin ligases that play an important role in the regulation and maintenance of proper Notch signaling and how perturbation in ubiquitination results in abnormal Notch signaling leading to a number of human diseases.
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Affiliation(s)
- Debdeep Dutta
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Vartika Sharma
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Mousumi Mutsuddi
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Ashim Mukherjee
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, India
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14
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Chen TH. Circulating microRNAs as potential biomarkers and therapeutic targets in spinal muscular atrophy. Ther Adv Neurol Disord 2021; 13:1756286420979954. [PMID: 33488772 PMCID: PMC7768327 DOI: 10.1177/1756286420979954] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 11/20/2020] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA), a leading genetic cause of infant death, is a neurodegenerative disease characterized by the selective loss of particular groups of motor neurons (MNs) in the anterior horn of the spinal cord with progressive muscle wasting. SMA is caused by a deficiency of the survival motor neuron (SMN) protein due to a homozygous deletion or mutation of the SMN1 gene. However, the molecular mechanisms whereby the SMN complex regulates MN functions are not fully elucidated. Emerging studies on SMA pathogenesis have turned the attention of researchers to RNA metabolism, given that increasingly identified SMN-associated modifiers are involved in both coding and non-coding RNA (ncRNA) processing. Among various ncRNAs, microRNAs (miRNAs) are the most studied in terms of regulation of posttranscriptional gene expression. Recently, the discovery that miRNAs are critical to MN function and survival led to the study of dysregulated miRNAs in SMA pathogenesis. Circulating miRNAs have drawn attention as a readily available biomarker due to their property of being clinically detectable in numerous human biofluids through non-invasive approaches. As there are recent promising findings from novel miRNA-based medicines, this article presents an extensive review of the most up-to-date studies connecting specific miRNAs to SMA pathogenesis and the potential applications of miRNAs as biomarkers and therapeutic targets for SMA.
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Affiliation(s)
- Tai-Heng Chen
- Department of Pediatrics, Division of Pediatric Emergency, Kaohsiung Medical University Hospital, School of Post-Baccalaureate Medicine, College of Medicine, Kaohsiung Medical University, No. 100, Tzyou 1st Road, Kaohsiung 80708, Taiwan
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15
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Bachiller S, Alonso-Bellido IM, Real LM, Pérez-Villegas EM, Venero JL, Deierborg T, Armengol JÁ, Ruiz R. The Ubiquitin Proteasome System in Neuromuscular Disorders: Moving Beyond Movement. Int J Mol Sci 2020; 21:E6429. [PMID: 32899400 DOI: 10.3390/ijms21176429] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/30/2020] [Accepted: 08/31/2020] [Indexed: 12/12/2022] Open
Abstract
Neuromuscular disorders (NMDs) affect 1 in 3000 people worldwide. There are more than 150 different types of NMDs, where the common feature is the loss of muscle strength. These disorders are classified according to their neuroanatomical location, as motor neuron diseases, peripheral nerve diseases, neuromuscular junction diseases, and muscle diseases. Over the years, numerous studies have pointed to protein homeostasis as a crucial factor in the development of these fatal diseases. The ubiquitin-proteasome system (UPS) plays a fundamental role in maintaining protein homeostasis, being involved in protein degradation, among other cellular functions. Through a cascade of enzymatic reactions, proteins are ubiquitinated, tagged, and translocated to the proteasome to be degraded. Within the ubiquitin system, we can find three main groups of enzymes: E1 (ubiquitin-activating enzymes), E2 (ubiquitin-conjugating enzymes), and E3 (ubiquitin-protein ligases). Only the ubiquitinated proteins with specific chain linkages (such as K48) will be degraded by the UPS. In this review, we describe the relevance of this system in NMDs, summarizing the UPS proteins that have been involved in pathological conditions and neuromuscular disorders, such as Spinal Muscular Atrophy (SMA), Charcot-Marie-Tooth disease (CMT), or Duchenne Muscular Dystrophy (DMD), among others. A better knowledge of the processes involved in the maintenance of proteostasis may pave the way for future progress in neuromuscular disorder studies and treatments.
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Wang P, Xia J, Zhang L, Zhao S, Li S, Wang H, Cheng S, Li H, Yin W, Pei D, Shu X. SNX17 Recruits USP9X to Antagonize MIB1-Mediated Ubiquitination and Degradation of PCM1 during Serum-Starvation-Induced Ciliogenesis. Cells 2019; 8:cells8111335. [PMID: 31671755 PMCID: PMC6912348 DOI: 10.3390/cells8111335] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/15/2019] [Accepted: 10/27/2019] [Indexed: 12/12/2022] Open
Abstract
Centriolar satellites are non-membrane cytoplasmic granules that deliver proteins to centrosome during centrosome biogenesis and ciliogenesis. Centriolar satellites are highly dynamic during cell cycle or ciliogenesis and how they are regulated remains largely unknown. We report here that sorting nexin 17 (SNX17) regulates the homeostasis of a subset of centriolar satellite proteins including PCM1, CEP131, and OFD1 during serum-starvation-induced ciliogenesis. Mechanistically, SNX17 recruits the deubiquitinating enzyme USP9X to antagonize the mindbomb 1 (MIB1)-induced ubiquitination and degradation of PCM1. SNX17 deficiency leads to enhanced degradation of USP9X as well as PCM1 and disrupts ciliogenesis upon serum starvation. On the other hand, SNX17 is dispensable for the homeostasis of PCM1 and USP9X in serum-containing media. These findings reveal a SNX17/USP9X mediated pathway essential for the homeostasis of centriolar satellites under serum starvation, and provide insight into the mechanism of USP9X in ciliogenesis, which may lead to a better understating of USP9X-deficiency-related human diseases such as X-linked mental retardation and neurodegenerative diseases.
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Affiliation(s)
- Pengtao Wang
- School of Life Sciences, University of Science and Technology of China, Hefei 230027, China.
- CAS Key Laboratory of Regenerative Biology, South China Institutes for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, China.
- Hefei Institute of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
| | - Jianhong Xia
- CAS Key Laboratory of Regenerative Biology, South China Institutes for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, China.
| | - Leilei Zhang
- CAS Key Laboratory of Regenerative Biology, South China Institutes for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, China.
| | - Shaoyang Zhao
- CAS Key Laboratory of Regenerative Biology, South China Institutes for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, China.
| | - Shengbiao Li
- CAS Key Laboratory of Regenerative Biology, South China Institutes for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, China.
| | - Haiyun Wang
- CAS Key Laboratory of Regenerative Biology, South China Institutes for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, China.
| | - Shan Cheng
- Hefei Institute of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
| | - Heying Li
- CAS Key Laboratory of Regenerative Biology, South China Institutes for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, China.
| | - Wenguang Yin
- CAS Key Laboratory of Regenerative Biology, South China Institutes for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, China.
| | - Duanqing Pei
- CAS Key Laboratory of Regenerative Biology, South China Institutes for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, China.
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory (GRMH-GDL), Guangzhou 510005, China.
| | - Xiaodong Shu
- CAS Key Laboratory of Regenerative Biology, South China Institutes for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, China.
- Hefei Institute of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory (GRMH-GDL), Guangzhou 510005, China.
- Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou 511436, China.
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17
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Ng SY, Mikhail A, Ljubicic V. Mechanisms of exercise-induced survival motor neuron expression in the skeletal muscle of spinal muscular atrophy-like mice. J Physiol 2019; 597:4757-4778. [PMID: 31361024 PMCID: PMC6767691 DOI: 10.1113/jp278454] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 07/26/2019] [Indexed: 12/29/2022] Open
Abstract
Key points Spinal muscular atrophy (SMA) is a health‐ and life‐limiting neuromuscular disorder caused by a deficiency in survival motor neuron (SMN) protein. While historically considered a motor neuron disease, current understanding of SMA emphasizes its systemic nature, which requires addressing affected peripheral tissues such as skeletal muscle in particular. Chronic physical activity is beneficial for SMA patients, but the cellular and molecular mechanisms of exercise biology are largely undefined in SMA. After a single bout of exercise, canonical responses such as skeletal muscle AMP‐activated protein kinase (AMPK), p38 mitogen‐activated protein kinase (p38) and peroxisome proliferator‐activated receptor γ coactivator 1α (PGC‐1α) activation were preserved in SMA‐like Smn2B/− animals. Furthermore, molecules involved in SMN transcription were also altered following physical activity. Collectively, these changes were coincident with an increase in full‐length SMN transcription and corrective SMN pre‐mRNA splicing. This study advances understanding of the exercise biology of SMA and highlights the AMPK–p38–PGC‐1α axis as a potential regulator of SMN expression in muscle.
Abstract Chronic physical activity is safe and effective in spinal muscular atrophy (SMA) patients, but the underlying cellular events that drive physiological adaptations are undefined. We examined the effects of a single bout of exercise on molecular mechanisms associated with adaptive remodelling in the skeletal muscle of Smn2B/− SMA‐like mice. Skeletal muscles were collected from healthy Smn2B/+ mice and Smn2B/− littermates at pre‐ (postnatal day (P) 9), early‐ (P13) and late‐ (P21) symptomatic stages to characterize SMA disease progression. Muscles were also collected from Smn2B/− animals exercised to fatigue on a motorized treadmill. Intracellular signalling and gene expression were examined using western blotting, confocal immunofluorescence microscopy, real‐time quantitative PCR and endpoint PCR assays. Basal skeletal muscle AMP‐activated protein kinase (AMPK) and p38 mitogen‐activated protein kinase (p38) expression and activity were not affected by SMA‐like conditions. Canonical exercise responses such as AMPK, p38 and peroxisome proliferator‐activated receptor γ coactivator‐1α (PGC‐1α) activation were observed following a bout of exercise in Smn2B/− animals. Furthermore, molecules involved in survival motor neuron (SMN) transcription, including protein kinase B (AKT) and extracellular signal‐regulated kinases (ERK)/ETS‐like gene 1 (ELK1), were altered following physical activity. Acute exercise was also able to mitigate aberrant proteolytic signalling in the skeletal muscle of Smn2B/− mice. Collectively, these changes were coincident with an exercise‐evoked increase in full‐length SMN mRNA expression. This study advances our understanding of the exercise biology of SMA and highlights the AMPK–p38–PGC‐1α axis as a potential regulator of SMN expression alongside AKT and ERK/ELK1 signalling. Spinal muscular atrophy (SMA) is a health‐ and life‐limiting neuromuscular disorder caused by a deficiency in survival motor neuron (SMN) protein. While historically considered a motor neuron disease, current understanding of SMA emphasizes its systemic nature, which requires addressing affected peripheral tissues such as skeletal muscle in particular. Chronic physical activity is beneficial for SMA patients, but the cellular and molecular mechanisms of exercise biology are largely undefined in SMA. After a single bout of exercise, canonical responses such as skeletal muscle AMP‐activated protein kinase (AMPK), p38 mitogen‐activated protein kinase (p38) and peroxisome proliferator‐activated receptor γ coactivator 1α (PGC‐1α) activation were preserved in SMA‐like Smn2B/− animals. Furthermore, molecules involved in SMN transcription were also altered following physical activity. Collectively, these changes were coincident with an increase in full‐length SMN transcription and corrective SMN pre‐mRNA splicing. This study advances understanding of the exercise biology of SMA and highlights the AMPK–p38–PGC‐1α axis as a potential regulator of SMN expression in muscle.
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Affiliation(s)
- Sean Y Ng
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Andrew Mikhail
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Vladimir Ljubicic
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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18
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Wiszniak S, Schwarz Q. Notch signalling defines dorsal root ganglia neuroglial fate choice during early neural crest cell migration. BMC Neurosci 2019; 20:21. [PMID: 31036074 PMCID: PMC6489353 DOI: 10.1186/s12868-019-0501-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 04/15/2019] [Indexed: 11/25/2022] Open
Abstract
Background The dorsal root ganglia (DRG) are a critical component of the peripheral nervous system, and function to relay somatosensory information from the body’s periphery to sensory perception centres within the brain. The DRG are primarily comprised of two cell types, sensory neurons and glia, both of which are neural crest-derived. Notch signalling is known to play an essential role in defining the neuronal or glial fate of bipotent neural crest progenitors that migrate from the dorsal ridge of the neural tube to the sites of the DRG. However, the involvement of Notch ligands in this process and the timing at which neuronal versus glial fate is acquired has remained uncertain. Results We have used tissue specific knockout of the E3 ubiquitin ligase mindbomb1 (Mib1) to remove the function of all Notch ligands in neural crest cells. Wnt1-Cre; Mib1fl/fl mice exhibit severe DRG defects, including a reduction in glial cells, and neuronal cell death later in development. By comparing formation of sensory neurons and glia with the expression and activation of Notch signalling in these mice, we define a critical period during embryonic development in which early migrating neural crest cells become biased toward neuronal and glial phenotypes. Conclusions We demonstrate active Notch signalling between neural crest progenitors as soon as trunk neural crest cells delaminate from the neural tube and during their early migration toward the site of the DRG. This data brings into question the timing of neuroglial fate specification in the DRG and suggest that it may occur much earlier than originally considered. Electronic supplementary material The online version of this article (10.1186/s12868-019-0501-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sophie Wiszniak
- Centre for Cancer Biology, University of South Australia and SA Pathology, North Terrace, Adelaide, SA, 5001, Australia
| | - Quenten Schwarz
- Centre for Cancer Biology, University of South Australia and SA Pathology, North Terrace, Adelaide, SA, 5001, Australia.
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19
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Chaytow H, Huang YT, Gillingwater TH, Faller KME. The role of survival motor neuron protein (SMN) in protein homeostasis. Cell Mol Life Sci 2018; 75:3877-3894. [PMID: 29872871 PMCID: PMC6182345 DOI: 10.1007/s00018-018-2849-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 12/11/2022]
Abstract
Ever since loss of survival motor neuron (SMN) protein was identified as the direct cause of the childhood inherited neurodegenerative disorder spinal muscular atrophy, significant efforts have been made to reveal the molecular functions of this ubiquitously expressed protein. Resulting research demonstrated that SMN plays important roles in multiple fundamental cellular homeostatic pathways, including a well-characterised role in the assembly of the spliceosome and biogenesis of ribonucleoproteins. More recent studies have shown that SMN is also involved in other housekeeping processes, including mRNA trafficking and local translation, cytoskeletal dynamics, endocytosis and autophagy. Moreover, SMN has been shown to influence mitochondria and bioenergetic pathways as well as regulate function of the ubiquitin-proteasome system. In this review, we summarise these diverse functions of SMN, confirming its key role in maintenance of the homeostatic environment of the cell.
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Affiliation(s)
- Helena Chaytow
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Yu-Ting Huang
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK.
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK.
| | - Kiterie M E Faller
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
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20
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Shorrock HK, van der Hoorn D, Boyd PJ, Llavero Hurtado M, Lamont DJ, Wirth B, Sleigh JN, Schiavo G, Wishart TM, Groen EJN, Gillingwater TH. UBA1/GARS-dependent pathways drive sensory-motor connectivity defects in spinal muscular atrophy. Brain 2018; 141:2878-2894. [PMID: 30239612 PMCID: PMC6158753 DOI: 10.1093/brain/awy237] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 07/25/2018] [Indexed: 01/09/2023] Open
Abstract
Deafferentation of motor neurons as a result of defective sensory-motor connectivity is a critical early event in the pathogenesis of spinal muscular atrophy, but the underlying molecular pathways remain unknown. We show that restoration of ubiquitin-like modifier-activating enzyme 1 (UBA1) was sufficient to correct sensory-motor connectivity in the spinal cord of mice with spinal muscular atrophy. Aminoacyl-tRNA synthetases, including GARS, were identified as downstream targets of UBA1. Regulation of GARS by UBA1 occurred via a non-canonical pathway independent of ubiquitylation. Dysregulation of UBA1/GARS pathways in spinal muscular atrophy mice disrupted sensory neuron fate, phenocopying GARS-dependent defects associated with Charcot-Marie-Tooth disease. Sensory neuron fate was corrected following restoration of UBA1 expression and UBA1/GARS pathways in spinal muscular atrophy mice. We conclude that defective sensory motor connectivity in spinal muscular atrophy results from perturbations in a UBA1/GARS pathway that modulates sensory neuron fate, thereby highlighting significant molecular and phenotypic overlap between spinal muscular atrophy and Charcot-Marie-Tooth disease.
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Affiliation(s)
- Hannah K Shorrock
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK,Present address: Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, University of Florida, 2033 Mowry Road, Gainesville, FL 32610, USA
| | - Dinja van der Hoorn
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Penelope J Boyd
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK,Present address: Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Maica Llavero Hurtado
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK, Roslin Institute, Royal (Dick) School of Veterinary Science, University of Edinburgh, UK
| | | | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Germany
| | - James N Sleigh
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, UK
| | - Giampietro Schiavo
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, UK, Discoveries Centre for Regenerative and Precision Medicine, University College London Campus, London, UK, UK Dementia Research Institute at UCL, London, UK
| | - Thomas M Wishart
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK, Roslin Institute, Royal (Dick) School of Veterinary Science, University of Edinburgh, UK
| | - Ewout J N Groen
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK,Correspondence may also be addressed to: Ewout J. N. Groen E-mail:
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK,Correspondence to: Thomas H. Gillingwater University of Edinburgh - Biomedical Sciences (Anatomy) Hugh Robson Building George Square Edinburgh, Scotland EH8 9XD, UK E-mail:
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21
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Maretina MA, Zheleznyakova GY, Lanko KM, Egorova AA, Baranov VS, Kiselev AV. Molecular Factors Involved in Spinal Muscular Atrophy Pathways as Possible Disease-modifying Candidates. Curr Genomics 2018; 19:339-355. [PMID: 30065610 PMCID: PMC6030859 DOI: 10.2174/1389202919666180101154916] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 12/15/2017] [Accepted: 12/18/2017] [Indexed: 01/07/2023] Open
Abstract
Spinal Muscular Atrophy (SMA) is a neuromuscular disorder caused by mutations in the SMN1 gene. Being a monogenic disease, it is characterized by high clinical heterogeneity. Variations in penetrance and severity of symptoms, as well as clinical discrepancies between affected family members can result from modifier genes influence on disease manifestation. SMN2 gene copy number is known to be the main phenotype modifier and there is growing evidence of additional factors contributing to SMA severity. Potential modifiers of spinal muscular atrophy can be found among the wide variety of different factors, such as multiple proteins interacting with SMN or promoting motor neuron survival, epigenetic modifications, transcriptional or splicing factors influencing SMN2 expression. Study of these factors enables to reveal mechanisms underlying SMA pathology and can have pronounced clinical application.
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Affiliation(s)
- Marianna A. Maretina
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
- Saint Petersburg State University, Universitetskaya emb. 7/9, 199034Saint Petersburg, Russia
| | - Galina Y. Zheleznyakova
- Department of Clinical Neuroscience, Karolinska Institutet, Karolinska Universitetssjukhuset, 171 76 Stockholm, Sweden
| | - Kristina M. Lanko
- Saint Petersburg State Institute of Technology, Moskovsky prospect, 26, Saint Petersburg190013, Russia
| | - Anna A. Egorova
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
| | - Vladislav S. Baranov
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
- Saint Petersburg State University, Universitetskaya emb. 7/9, 199034Saint Petersburg, Russia
| | - Anton V. Kiselev
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
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22
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Nielsen JC, Nordgaard C, Tollenaere MAX, Bekker-Jensen S. Osmotic Stress Blocks Mobility and Dynamic Regulation of Centriolar Satellites. Cells 2018; 7:E65. [PMID: 29932434 PMCID: PMC6070812 DOI: 10.3390/cells7070065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/19/2018] [Accepted: 06/20/2018] [Indexed: 12/15/2022] Open
Abstract
Centriolar satellites (CS) are small proteinaceous granules that cluster around the centrosome and serve as cargo vehicles for centrosomal proteins. It is generally accepted that CS support a number of canonical and specialized centrosome functions. Consequently, these highly dynamic structures are the target of regulation by several cellular signalling pathways. Two decades of research have led to the identification of a large number of molecular components and new biological roles of CS. Here, we summarize the latest advances in the continuous efforts to uncover the compositional, functional, dynamic and regulatory aspects of CS. We also report on our discovery that osmotic stress conditions render CS immobile and insensitive to remodelling. Upon a range of p38-activating stimuli, MK2 phosphorylates the CS component CEP131, resulting in 14-3-3 binding and a block to CS formation. This normally manifests as a rapid cellular depletion of satellites. In the case of osmotic stress, a potent inducer of p38 activity, CS translocation and dissolution is blocked, with the net result that satellites persist in an immobile state directly adjacent to the centrosome. Our results highlight a unique scenario where p38 activation and CS depletion is uncoupled, with potential implications for physiological and pathological osmotic stress responses.
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Affiliation(s)
- Julie C Nielsen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark.
| | - Cathrine Nordgaard
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark.
| | - Maxim A X Tollenaere
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark.
| | - Simon Bekker-Jensen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark.
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23
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Rodriguez-Muela N, Parkhitko A, Grass T, Gibbs RM, Norabuena EM, Perrimon N, Singh R, Rubin LL. Blocking p62-dependent SMN degradation ameliorates spinal muscular atrophy disease phenotypes. J Clin Invest 2018; 128:3008-3023. [PMID: 29672276 DOI: 10.1172/jci95231] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 04/12/2018] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA), a degenerative motor neuron (MN) disease, caused by loss of functional survival of motor neuron (SMN) protein due to SMN1 gene mutations, is a leading cause of infant mortality. Increasing SMN levels ameliorates the disease phenotype and is unanimously accepted as a therapeutic approach for patients with SMA. The ubiquitin/proteasome system is known to regulate SMN protein levels; however, whether autophagy controls SMN levels remains poorly explored. Here, we show that SMN protein is degraded by autophagy. Pharmacological and genetic inhibition of autophagy increases SMN levels, while induction of autophagy decreases these levels. SMN degradation occurs via its interaction with the autophagy adapter p62 (also known as SQSTM1). We also show that SMA neurons display reduced autophagosome clearance, increased p62 and ubiquitinated proteins levels, and hyperactivated mTORC1 signaling. Importantly, reducing p62 levels markedly increases SMN and its binding partner gemin2, promotes MN survival, and extends lifespan in fly and mouse SMA models, revealing p62 as a potential new therapeutic target for the treatment of SMA.
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Affiliation(s)
- Natalia Rodriguez-Muela
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
| | - Andrey Parkhitko
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Tobias Grass
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
| | - Rebecca M Gibbs
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
| | - Erika M Norabuena
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.,Howard Hughes Medical Institute, Boston, Massachusetts, USA
| | - Rajat Singh
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Lee L Rubin
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
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24
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Ratliff M, Hill-Harfe KL, Gleason EJ, Ling H, Kroft TL, L'Hernault SW. MIB-1 Is Required for Spermatogenesis and Facilitates LIN-12 and GLP-1 Activity in Caenorhabditis elegans. Genetics 2018; 209:173-193. [PMID: 29531012 PMCID: PMC5935030 DOI: 10.1534/genetics.118.300807] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 02/26/2018] [Indexed: 12/11/2022] Open
Abstract
Covalent attachment of ubiquitin to substrate proteins changes their function or marks them for proteolysis, and the specificity of ubiquitin attachment is mediated by the numerous E3 ligases encoded by animals. Mind Bomb is an essential E3 ligase during Notch pathway signaling in insects and vertebrates. While Caenorhabditis elegans encodes a Mind Bomb homolog (mib-1), it has never been recovered in the extensive Notch suppressor/enhancer screens that have identified numerous pathway components. Here, we show that C. elegans mib-1 null mutants have a spermatogenesis-defective phenotype that results in a heterogeneous mixture of arrested spermatocytes, defective spermatids, and motility-impaired spermatozoa. mib-1 mutants also have chromosome segregation defects during meiosis, molecular null mutants are intrinsically temperature-sensitive, and many mib-1 spermatids contain large amounts of tubulin. These phenotypic features are similar to the endogenous RNA intereference (RNAi) mutants, but mib-1 mutants do not affect RNAi. MIB-1 protein is expressed throughout the germ line with peak expression in spermatocytes followed by segregation into the residual body during spermatid formation. C. elegans mib-1 expression, while upregulated during spermatogenesis, also occurs somatically, including in vulva precursor cells. Here, we show that mib-1 mutants suppress both lin-12 and glp-1 (C. elegans Notch) gain-of-function mutants, restoring anchor cell formation and a functional vulva to the former and partly restoring oocyte production to the latter. However, suppressed hermaphrodites are only observed when grown at 25°, and they are self-sterile. This probably explains why mib-1 was not previously recovered as a Notch pathway component in suppressor/enhancer selection experiments.
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Affiliation(s)
- Miriam Ratliff
- Department of Biology, Emory University, Atlanta, Georgia 30322
| | - Katherine L Hill-Harfe
- Department of Biology, Emory University, Atlanta, Georgia 30322
- Program in Genetics and Molecular Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, Georgia 30322
| | | | - Huiping Ling
- Department of Biology, Emory University, Atlanta, Georgia 30322
| | - Tim L Kroft
- Department of Biology, Emory University, Atlanta, Georgia 30322
| | - Steven W L'Hernault
- Department of Biology, Emory University, Atlanta, Georgia 30322
- Program in Genetics and Molecular Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, Georgia 30322
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25
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Abstract
Spinal muscular atrophy (SMA) is a devastating motor neuron disease that predominantly affects children and represents the most common cause of hereditary infant mortality. The condition results from deleterious variants in SMN1, which lead to depletion of the survival motor neuron protein (SMN). Now, 20 years after the discovery of this genetic defect, a major milestone in SMA and motor neuron disease research has been reached with the approval of the first disease-modifying therapy for SMA by US and European authorities - the antisense oligonucleotide nusinersen. At the same time, promising data from early-stage clinical trials of SMN1 gene therapy have indicated that additional therapeutic options are likely to emerge for patients with SMA in the near future. However, the approval of nusinersen has generated a number of immediate and substantial medical, ethical and financial implications that have the potential to resonate beyond the specific treatment of SMA. Here, we provide an overview of the rapidly evolving therapeutic landscape for SMA, highlighting current achievements and future opportunities. We also discuss how these developments are providing important lessons for the emerging second generation of combinatorial ('SMN-plus') therapies that are likely to be required to generate robust treatments that are effective across a patient's lifespan.
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Affiliation(s)
- Ewout J N Groen
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK.,Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, UK
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK
| | - Thomas H Gillingwater
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK.,Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, UK
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26
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Gray KM, Kaifer KA, Baillat D, Wen Y, Bonacci TR, Ebert AD, Raimer AC, Spring AM, Have ST, Glascock JJ, Gupta K, Van Duyne GD, Emanuele MJ, Lamond AI, Wagner EJ, Lorson CL, Matera AG. Self-oligomerization regulates stability of survival motor neuron protein isoforms by sequestering an SCF Slmb degron. Mol Biol Cell 2018; 29:96-110. [PMID: 29167380 PMCID: PMC5909936 DOI: 10.1091/mbc.e17-11-0627] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 11/14/2017] [Indexed: 12/16/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by homozygous mutations in human SMN1 Expression of a duplicate gene (SMN2) primarily results in skipping of exon 7 and production of an unstable protein isoform, SMNΔ7. Although SMN2 exon skipping is the principal contributor to SMA severity, mechanisms governing stability of survival motor neuron (SMN) isoforms are poorly understood. We used a Drosophila model system and label-free proteomics to identify the SCFSlmb ubiquitin E3 ligase complex as a novel SMN binding partner. SCFSlmb interacts with a phosphor degron embedded within the human and fruitfly SMN YG-box oligomerization domains. Substitution of a conserved serine (S270A) interferes with SCFSlmb binding and stabilizes SMNΔ7. SMA-causing missense mutations that block multimerization of full-length SMN are also stabilized in the degron mutant background. Overexpression of SMNΔ7S270A, but not wild-type (WT) SMNΔ7, provides a protective effect in SMA model mice and human motor neuron cell culture systems. Our findings support a model wherein the degron is exposed when SMN is monomeric and sequestered when SMN forms higher-order multimers.
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Affiliation(s)
- Kelsey M Gray
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
| | - Kevin A Kaifer
- Molecular Pathogenesis and Therapeutics Program, Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211
| | - David Baillat
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77550
| | - Ying Wen
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
| | - Thomas R Bonacci
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599
| | - Allison D Ebert
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Amanda C Raimer
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
| | - Ashlyn M Spring
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
| | - Sara Ten Have
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD15EH, UK
| | - Jacqueline J Glascock
- Molecular Pathogenesis and Therapeutics Program, Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211
| | - Kushol Gupta
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Gregory D Van Duyne
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Michael J Emanuele
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599
| | - Angus I Lamond
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD15EH, UK
| | - Eric J Wagner
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77550
| | - Christian L Lorson
- Molecular Pathogenesis and Therapeutics Program, Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211
| | - A Gregory Matera
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
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27
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Wang L, Cai B, Zhou S, Zhu H, Qu L, Wang X, Chen Y. RNA-seq reveals transcriptome changes in goats following myostatin gene knockout. PLoS One 2017; 12:e0187966. [PMID: 29228005 DOI: 10.1371/journal.pone.0187966] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Accepted: 10/30/2017] [Indexed: 12/17/2022] Open
Abstract
Myostatin (MSTN) is a powerful negative regulator of skeletal muscle mass in mammalian species that is primarily expressed in skeletal muscles, and mutations of its encoding gene can result in the double-muscling trait. In this study, the CRISPR/Cas9 technique was used to edit MSTN in Shaanbei Cashmere goats and generate knockout animals. RNA sequencing was used to determine and compare the transcriptome profiles of the muscles from three wild-type (WT) goats, three fibroblast growth factor 5 (FGF5) knockout goats (FGF5+/- group) and three goats with disrupted expression of both the FGF5 and MSTN genes (FM+/- group). The sequence reads were obtained using the Illumina HiSeq 2000 system and mapped to the Capra hircus reference genome using TopHat (v2.0.9). In total, 68.93, 62.04 and 66.26 million clean sequencing reads were obtained from the WT, FM+/- and FGF5+/- groups, respectively. There were 201 differentially expressed genes (DEGs) between the WT and FGF5+/- groups, with 86 down- and 115 up-regulated genes in the FGF5+/- group. Between the WT and FM+/- groups, 121 DEGs were identified, including 81 down- and 40 up-regulated genes in the FM+/- group. A total of 198 DEGs were detected between the FGF5+/- group and FM+/- group, with 128 down- and 70 up-regulated genes in the FM+/- group. At the transcriptome level, we found substantial changes in genes involved in fatty acid metabolism and the biosynthesis of unsaturated fatty acids, such as stearoyl-CoA dehydrogenase, 3-hydroxyacyl-CoA dehydratase 2, ELOVL fatty acid elongase 6 and fatty acid synthase, suggesting that the expression levels of these genes may be directly regulated by MSTN and that these genes are likely downstream targets of MSTN with potential roles in lipid metabolism in goats. Moreover, five randomly selected DEGs were further validated with qRT-PCR, and the results were consistent with the transcriptome analysis. The present study provides insight into the unique transcriptome profile of the MSTN knockout goat, which is a valuable resource for studying goat genomics.
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28
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Sánchez-Lanzas R, Castaño JG. Lysine-Less Variants of Spinal Muscular Atrophy SMN and SMNΔ7 Proteins Are Degraded by the Proteasome Pathway. Int J Mol Sci 2017; 18:E2667. [PMID: 29292768 DOI: 10.3390/ijms18122667] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 11/17/2022] Open
Abstract
Spinal muscular atrophy is due to mutations affecting the SMN1 gene coding for the full-length protein (survival motor neuron; SMN) and the SMN2 gene that preferentially generates an exon 7-deleted protein (SMNΔ7) by alternative splicing. To study SMN and SMNΔ7 degradation in the cell, we have used tagged versions at the N- (Flag) or C-terminus (V5) of both proteins. Transfection of those constructs into HeLa cells and treatment with cycloheximide showed that those protein constructs were degraded. Proteasomal degradation usually requires prior lysine ubiquitylation. Surprisingly, lysine-less variants of both proteins tagged either at N- (Flag) or C-terminus (V5) were also degraded. The degradation of the endogenous SMN protein, and the protein constructs mentioned above, was mediated by the proteasome, as it was blocked by lactacystin, a specific and irreversible proteasomal inhibitor. The results obtained allowed us to conclude that SMN and SMNΔ7 proteasomal degradation did not absolutely require internal ubiquitylation nor N-terminal ubiquitylation (prevented by N-terminal tagging). While the above conclusions are firmly supported by the experimental data presented, we discuss and justify the need of deep proteomic techniques for the study of SMN complex components (orphan and bound) turn-over to understand the physiological relevant mechanisms of degradation of SMN and SMNΔ7 in the cell.
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29
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Lafarga V, Tapia O, Sharma S, Bengoechea R, Stoecklin G, Lafarga M, Berciano MT. CBP-mediated SMN acetylation modulates Cajal body biogenesis and the cytoplasmic targeting of SMN. Cell Mol Life Sci 2018; 75:527-46. [PMID: 28879433 DOI: 10.1007/s00018-017-2638-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/09/2017] [Accepted: 08/29/2017] [Indexed: 01/12/2023]
Abstract
The survival of motor neuron (SMN) protein plays an essential role in the biogenesis of spliceosomal snRNPs and the molecular assembly of Cajal bodies (CBs). Deletion of or mutations in the SMN1 gene cause spinal muscular atrophy (SMA) with degeneration and loss of motor neurons. Reduced SMN levels in SMA lead to deficient snRNP biogenesis with consequent splicing pathology. Here, we demonstrate that SMN is a novel and specific target of the acetyltransferase CBP (CREB-binding protein). Furthermore, we identify lysine (K) 119 as the main acetylation site in SMN. Importantly, SMN acetylation enhances its cytoplasmic localization, causes depletion of CBs, and reduces the accumulation of snRNPs in nuclear speckles. In contrast, the acetylation-deficient SMNK119R mutant promotes formation of CBs and a novel category of promyelocytic leukemia (PML) bodies enriched in this protein. Acetylation increases the half-life of SMN protein, reduces its cytoplasmic diffusion rate and modifies its interactome. Hence, SMN acetylation leads to its dysfunction, which explains the ineffectiveness of HDAC (histone deacetylases) inhibitors in SMA therapy despite their potential to increase SMN levels.
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30
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Abera MB, Xiao J, Nofziger J, Titus S, Southall N, Zheng W, Moritz KE, Ferrer M, Cherry JJ, Androphy EJ, Wang A, Xu X, Austin C, Fischbeck KH, Marugan JJ, Burnett BG. ML372 blocks SMN ubiquitination and improves spinal muscular atrophy pathology in mice. JCI Insight 2016; 1:e88427. [PMID: 27882347 DOI: 10.1172/jci.insight.88427] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease and one of the leading inherited causes of infant mortality. SMA results from insufficient levels of the survival motor neuron (SMN) protein, and studies in animal models of the disease have shown that increasing SMN protein levels ameliorates the disease phenotype. Our group previously identified and optimized a new series of small molecules, with good potency and toxicity profiles and reasonable pharmacokinetics, that were able to increase SMN protein levels in SMA patient-derived cells. We show here that ML372, a representative of this series, almost doubles the half-life of residual SMN protein expressed from the SMN2 locus by blocking its ubiquitination and subsequent degradation by the proteasome. ML372 increased SMN protein levels in muscle, spinal cord, and brain tissue of SMA mice. Importantly, ML372 treatment improved the righting reflex and extended survival of a severe mouse model of SMA. These results demonstrate that slowing SMN degradation by selectively inhibiting its ubiquitination can improve the motor phenotype and lifespan of SMA model mice.
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Affiliation(s)
- Mahlet B Abera
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine, Bethesda, Maryland, USA
| | - Jingbo Xiao
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Jonathan Nofziger
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Steve Titus
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Noel Southall
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Wei Zheng
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Kasey E Moritz
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine, Bethesda, Maryland, USA
| | - Marc Ferrer
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Jonathan J Cherry
- Department of Dermatology,, School of Medicine, Indiana University, Indianapolis, Indiana, USA
| | - Elliot J Androphy
- Department of Dermatology,, School of Medicine, Indiana University, Indianapolis, Indiana, USA
| | - Amy Wang
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Xin Xu
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Christopher Austin
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Kenneth H Fischbeck
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Juan J Marugan
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Barrington G Burnett
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine, Bethesda, Maryland, USA
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31
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Abstract
The biogenesis of small nuclear ribonucleoproteins (snRNPs), small Cajal body-specific RNPs (scaRNPs), small nucleolar RNPs (snoRNPs) and the telomerase RNP involves Cajal bodies (CBs). Although many components enriched in the CB contain post-translational modifications (PTMs), little is known about how these modifications impact individual protein function within the CB and, in concert with other modified factors, collectively regulate CB activity. Since all components of the CB also reside in other cellular locations, it is also important that we understand how PTMs affect the subcellular localization of CB components. In this review, we explore the current knowledge of PTMs on the activity of proteins known to enrich in CBs in an effort to highlight current progress as well as illuminate paths for future investigation.
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Affiliation(s)
- Michael D Hebert
- a Department of Biochemistry , The University of Mississippi Medical Center , Jackson , MS , USA
| | - Aaron R Poole
- a Department of Biochemistry , The University of Mississippi Medical Center , Jackson , MS , USA
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32
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Matsuda M, Rand K, Palardy G, Shimizu N, Ikeda H, Dalle Nogare D, Itoh M, Chitnis AB. Epb41l5 competes with Delta as a substrate for Mib1 to coordinate specification and differentiation of neurons. Development 2016; 143:3085-96. [PMID: 27510968 DOI: 10.1242/dev.138743] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 07/26/2016] [Indexed: 01/04/2023]
Abstract
We identified Erythrocyte membrane protein band 4.1-like 5 (Epb41l5) as a substrate for the E3 ubiquitin ligase Mind bomb 1 (Mib1), which is essential for activation of Notch signaling. Although loss of Epb41l5 does not significantly alter the pattern of neural progenitor cells (NPCs) specified as neurons at the neural plate stage, it delays their delamination and differentiation after neurulation when NPCs normally acquire organized apical junctional complexes (AJCs) in the zebrafish hindbrain. Delays in differentiation are reduced by knocking down N-cadherin, a manipulation expected to help destabilize adherens junctions (AJs). This suggested that delays in neuronal differentiation in epb41l5-deficient embryos are related to a previously described role for Epb41l5 in facilitating disassembly of cadherin-dependent AJCs. Mib1 ubiquitylates Epb41l5 to promote its degradation. DeltaD can compete with Epb41l5 to reduce Mib1-dependent Epb41l5 degradation. In this context, increasing the number of NPCs specified to become neurons, i.e. cells expressing high levels of DeltaD, stabilizes Epb41l5 in the embryo. Together, these observations suggest that relatively high levels of Delta stabilize Epb41l5 in NPCs specified as neurons. This, we suggest, helps coordinate NPC specification with Epb41l5-dependent delamination and differentiation as neurons.
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Affiliation(s)
- Miho Matsuda
- Department of Cell Biology and Molecular Medicine, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, NJ 07103, USA Section on Neural Developmental Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kinneret Rand
- Section on Neural Developmental Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Greg Palardy
- Section on Neural Developmental Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nobuyuki Shimizu
- Department of Cell Biology and Molecular Medicine, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, NJ 07103, USA
| | - Hiromi Ikeda
- Section on Neural Developmental Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Damian Dalle Nogare
- Section on Neural Developmental Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Motoyuki Itoh
- Section on Neural Developmental Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA Department of Pharmacology, Chiba University, Chiba 260-8675, Japan
| | - Ajay B Chitnis
- Section on Neural Developmental Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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Powis RA, Karyka E, Boyd P, Côme J, Jones RA, Zheng Y, Szunyogova E, Groen EJ, Hunter G, Thomson D, Wishart TM, Becker CG, Parson SH, Martinat C, Azzouz M, Gillingwater TH. Systemic restoration of UBA1 ameliorates disease in spinal muscular atrophy. JCI Insight 2016; 1:e87908. [PMID: 27699224 PMCID: PMC5033939 DOI: 10.1172/jci.insight.87908] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The autosomal recessive neuromuscular disease spinal muscular atrophy (SMA) is caused by loss of survival motor neuron (SMN) protein. Molecular pathways that are disrupted downstream of SMN therefore represent potentially attractive therapeutic targets for SMA. Here, we demonstrate that therapeutic targeting of ubiquitin pathways disrupted as a consequence of SMN depletion, by increasing levels of one key ubiquitination enzyme (ubiquitin-like modifier activating enzyme 1 [UBA1]), represents a viable approach for treating SMA. Loss of UBA1 was a conserved response across mouse and zebrafish models of SMA as well as in patient induced pluripotent stem cell-derive motor neurons. Restoration of UBA1 was sufficient to rescue motor axon pathology and restore motor performance in SMA zebrafish. Adeno-associated virus serotype 9-UBA1 (AAV9-UBA1) gene therapy delivered systemic increases in UBA1 protein levels that were well tolerated over a prolonged period in healthy control mice. Systemic restoration of UBA1 in SMA mice ameliorated weight loss, increased survival and motor performance, and improved neuromuscular and organ pathology. AAV9-UBA1 therapy was also sufficient to reverse the widespread molecular perturbations in ubiquitin homeostasis that occur during SMA. We conclude that UBA1 represents a safe and effective therapeutic target for the treatment of both neuromuscular and systemic aspects of SMA.
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Affiliation(s)
- Rachael A. Powis
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Evangelia Karyka
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Penelope Boyd
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Julien Côme
- INSERM/UEVE UMR861, Institute for Stem cell Therapy and Exploration of Monogenic Diseases (I-Stem), Corbeil-Essonnes, France
| | - Ross A. Jones
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Yinan Zheng
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Eva Szunyogova
- Euan MacDonald Centre for Motor Neurone Disease Research and,The Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Ewout J.N. Groen
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Gillian Hunter
- Euan MacDonald Centre for Motor Neurone Disease Research and,Department of Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom
| | | | - Thomas M. Wishart
- Euan MacDonald Centre for Motor Neurone Disease Research and,The Roslin Institute, and
| | - Catherina G. Becker
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom
| | - Simon H. Parson
- Euan MacDonald Centre for Motor Neurone Disease Research and,The Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Cécile Martinat
- INSERM/UEVE UMR861, Institute for Stem cell Therapy and Exploration of Monogenic Diseases (I-Stem), Corbeil-Essonnes, France
| | - Mimoun Azzouz
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
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Guo B, McMillan BJ, Blacklow SC. Structure and function of the Mind bomb E3 ligase in the context of Notch signal transduction. Curr Opin Struct Biol 2016; 41:38-45. [PMID: 27285058 DOI: 10.1016/j.sbi.2016.05.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 05/23/2016] [Accepted: 05/23/2016] [Indexed: 12/16/2022]
Abstract
The Notch signaling pathway has a critical role in cell fate determination and tissue homeostasis in a variety of different lineages. In the context of normal Notch signaling, the Notch receptor of the 'signal-receiving' cell is activated in trans by a Notch ligand from a neighboring 'signal-sending' cell. Genetic studies in several model organisms have established that ubiquitination of the Notch ligand, and its regulated endocytosis, is essential for transmission of this activation signal. In mammals, this ubiquitination step is dependent on the protein Mind bomb 1 (Mib1), a large multi-domain RING-type E3 ligase, and its direct interaction with the intracellular tails of Notch ligand molecules. Here, we discuss our current understanding of Mind bomb structure and mechanism in the context of Notch signaling and beyond.
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Han KJ, Foster D, Harhaj EW, Dzieciatkowska M, Hansen K, Liu CW. Monoubiquitination of survival motor neuron regulates its cellular localization and Cajal body integrity. Hum Mol Genet 2016; 25:1392-405. [PMID: 26908624 DOI: 10.1093/hmg/ddw021] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 01/25/2016] [Indexed: 12/13/2022] Open
Abstract
Low levels of the survival motor neuron (SMN) protein cause spinal muscular atrophy, the leading genetic disorder for infant mortality. SMN is ubiquitously expressed in various cell types and localizes in both the cytoplasm and the nucleus, where it concentrates in two subnuclear structures termed Cajal body (CB) and gems. In addition, SMN can also be detected in the nucleolus of neurons. Mechanisms that control SMN sorting in the cell remain largely unknown. Here, we report that the ubiquitin (Ub) ligase Itch directly interacts with and monoubiquitinates SMN. Monoubiquitination of SMN has a mild effect on promoting proteasomal degradation of SMN. We generated two SMN mutants, SMN(K0), in which all lysines are mutated to arginines and thereby abolishing SMN ubiquitination, and Ub-SMN(K0), in which a single Ub moiety is fused at the N-terminus of SMN(K0) and thereby mimicking SMN monoubiquitination. Immunostaining assays showed that SMN(K0) mainly localizes in the nucleus, whereas Ub-SMN(K0) localizes in both the cytoplasm and the nucleolus in neuronal SH-SY5Y cells. Interestingly, canonical CB foci and coilin/small nuclear ribonucleoprotein (snRNP) co-localization are significantly impaired in SH-SY5Y cells stably expressing SMN(K0) or Ub-SMN(K0). Thus, our studies discover that Itch monoubiquitinates SMN and monoubiquitination of SMN plays an important role in regulating its cellular localization. Moreover, mislocalization of SMN disrupts CB integrity and likely impairs snRNP maturation.
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Affiliation(s)
- Ke-Jun Han
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80015, USA and
| | - Daniel Foster
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80015, USA and
| | - Edward W Harhaj
- Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - Monika Dzieciatkowska
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80015, USA and
| | - Kirk Hansen
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80015, USA and
| | - Chang-Wei Liu
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80015, USA and
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Foran E, Kwon DY, Nofziger JH, Arnold ES, Hall MD, Fischbeck KH, Burnett BG. CNS uptake of bortezomib is enhanced by P-glycoprotein inhibition: implications for spinal muscular atrophy. Neurobiol Dis 2016; 88:118-24. [PMID: 26792401 DOI: 10.1016/j.nbd.2016.01.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 12/11/2015] [Accepted: 01/09/2016] [Indexed: 12/12/2022] Open
Abstract
The development of therapeutics for neurological disorders is constrained by limited access to the central nervous system (CNS). ATP-binding cassette (ABC) transporters, particularly P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP), are expressed on the luminal surface of capillaries in the CNS and transport drugs out of the endothelium back into the blood against the concentration gradient. Survival motor neuron (SMN) protein, which is deficient in spinal muscular atrophy (SMA), is a target of the ubiquitin proteasome system. Inhibiting the proteasome in a rodent model of SMA with bortezomib increases SMN protein levels in peripheral tissues but not the CNS, because bortezomib has poor CNS penetrance. We sought to determine if we could inhibit SMN degradation in the CNS of SMA mice with a combination of bortezomib and the ABC transporter inhibitor tariquidar. In cultured cells we show that bortezomib is a substrate of P-gp. Mass spectrometry analysis demonstrated that intraperitoneal co-administration of tariquidar increased the CNS penetrance of bortezomib, and reduced proteasome activity in the brain and spinal cord. This correlated with increased SMN protein levels and improved survival and motor function of SMA mice. These findings show that CNS penetrance of treatment for this neurological disorder can be improved by inhibiting drug efflux at the blood-brain barrier.
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Affiliation(s)
- Emily Foran
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, United States.
| | - Deborah Y Kwon
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, United States; Department of Neuroscience, Brown University, United States
| | - Jonathan H Nofziger
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, United States
| | - Eveline S Arnold
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, United States
| | - Matthew D Hall
- CE Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, United States
| | - Kenneth H Fischbeck
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, United States
| | - Barrington G Burnett
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Services, United States
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37
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Powis RA, Mutsaers CA, Wishart TM, Hunter G, Wirth B, Gillingwater TH. Increased levels of UCHL1 are a compensatory response to disrupted ubiquitin homeostasis in spinal muscular atrophy and do not represent a viable therapeutic target. Neuropathol Appl Neurobiol 2015; 40:873-87. [PMID: 25041530 DOI: 10.1111/nan.12168] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 06/25/2014] [Indexed: 12/21/2022]
Abstract
AIM Levels of ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) are robustly increased in spinal muscular atrophy (SMA) patient fibroblasts and mouse models. We therefore wanted to establish whether changes in UCHL1 contribute directly to disease pathogenesis, and to assess whether pharmacological inhibition of UCHL1 represents a viable therapeutic option for SMA. METHODS SMA mice and control littermates received a pharmacological UCHL1 inhibitor (LDN-57444) or DMSO vehicle. Survival and weight were monitored daily, a righting test of motor performance was performed, and motor neurone loss, muscle fibre atrophy and neuromuscular junction pathology were all quantified. Ubiquitin-like modifier activating enzyme 1 (Uba1) was then pharmacologically inhibited in neurones in vitro to examine the relationship between Uba1 levels and UCHL1 in SMA. RESULTS Pharmacological inhibition of UCHL1 failed to improve survival, motor symptoms or neuromuscular pathology in SMA mice and actually precipitated the onset of weight loss. LDN-57444 treatment significantly decreased spinal cord mono-ubiquitin levels, further exacerbating ubiquitination defects in SMA mice. Pharmacological inhibition of Uba1, levels of which are robustly reduced in SMA, was sufficient to induce accumulation of UCHL1 in primary neuronal cultures. CONCLUSION Pharmacological inhibition of UCHL1 exacerbates rather than ameliorates disease symptoms in a mouse model of SMA. Thus, pharmacological inhibition of UCHL1 is not a viable therapeutic target for SMA. Moreover, increased levels of UCHL1 in SMA likely represent a downstream consequence of decreased Uba1 levels, indicative of an attempted supportive compensatory response to defects in ubiquitin homeostasis caused by low levels of SMN protein.
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Affiliation(s)
- Rachael A Powis
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK; Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
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38
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Mertz J, Tan H, Pagala V, Bai B, Chen PC, Li Y, Cho JH, Shaw T, Wang X, Peng J. Sequential Elution Interactome Analysis of the Mind Bomb 1 Ubiquitin Ligase Reveals a Novel Role in Dendritic Spine Outgrowth. Mol Cell Proteomics 2015; 14:1898-910. [PMID: 25931508 DOI: 10.1074/mcp.m114.045898] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Indexed: 11/06/2022] Open
Abstract
The mind bomb 1 (Mib1) ubiquitin ligase is essential for controlling metazoan development by Notch signaling and possibly the Wnt pathway. It is also expressed in postmitotic neurons and regulates neuronal morphogenesis and synaptic activity by mechanisms that are largely unknown. We sought to comprehensively characterize the Mib1 interactome and study its potential function in neuron development utilizing a novel sequential elution strategy for affinity purification, in which Mib1 binding proteins were eluted under different stringency and then quantified by the isobaric labeling method. The strategy identified the Mib1 interactome with both deep coverage and the ability to distinguish high-affinity partners from low-affinity partners. A total of 817 proteins were identified during the Mib1 affinity purification, including 56 high-affinity partners and 335 low-affinity partners, whereas the remaining 426 proteins are likely copurified contaminants or extremely weak binding proteins. The analysis detected all previously known Mib1-interacting proteins and revealed a large number of novel components involved in Notch and Wnt pathways, endocytosis and vesicle transport, the ubiquitin-proteasome system, cellular morphogenesis, and synaptic activities. Immunofluorescence studies further showed colocalization of Mib1 with five selected proteins: the Usp9x (FAM) deubiquitinating enzyme, alpha-, beta-, and delta-catenins, and CDKL5. Mutations of CDKL5 are associated with early infantile epileptic encephalopathy-2 (EIEE2), a severe form of mental retardation. We found that the expression of Mib1 down-regulated the protein level of CDKL5 by ubiquitination, and antagonized CDKL5 function during the formation of dendritic spines. Thus, the sequential elution strategy enables biochemical characterization of protein interactomes; and Mib1 analysis provides a comprehensive interactome for investigating its role in signaling networks and neuronal development.
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Affiliation(s)
- Joseph Mertz
- From the ‡Departments of Structural Biology and Developmental Neurobiology
| | | | | | - Bing Bai
- From the ‡Departments of Structural Biology and Developmental Neurobiology
| | - Ping-Chung Chen
- From the ‡Departments of Structural Biology and Developmental Neurobiology
| | - Yuxin Li
- From the ‡Departments of Structural Biology and Developmental Neurobiology
| | | | - Timothy Shaw
- §St. Jude Proteomics Facility, ¶Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | | | - Junmin Peng
- From the ‡Departments of Structural Biology and Developmental Neurobiology, §St. Jude Proteomics Facility,
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Murtaza M, Jolly LA, Gecz J, Wood SA. La FAM fatale: USP9X in development and disease. Cell Mol Life Sci 2015; 72:2075-89. [PMID: 25672900 PMCID: PMC4427618 DOI: 10.1007/s00018-015-1851-0] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/02/2015] [Accepted: 02/04/2015] [Indexed: 11/12/2022]
Abstract
Deubiquitylating enzymes (DUBs), act downstream of ubiquitylation. As such, these post-post-translational modifiers function as the final arbitrators of a protein substrate’s ubiquitylation status, thus regulating its fate. In most instances, DUBs moderate the absolute level of a substrate, its locality or activity, rather than being an “all-or-none” phenomenon. Yet, disruption of this quantitative regulation can produce dramatic qualitative differences. The ubiquitin-specific protease 9X (USP9X/FAM) is a substrate-specific DUB, which displays an extraordinarily high level of sequence conservation from Drosophila to mammals. It is primarily the recent revelations of USP9X’s pivotal role in human cancers, both as oncogene or tumour suppressor, in developmental disorders including intellectual disability, epilepsy, autism and developmental delay that has led to a subsequent re-examination of its molecular and cellular functions. Results from experimental animal models have implicated USP9X in neurodegeneration, including Parkinson’s and Alzheimer’s disease, as well as autoimmune diseases. In this review, we describe the current and accumulated knowledge on the molecular, cellular and developmental aspects of USP9X function within the context of the biological consequences during normal development and disease.
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Affiliation(s)
- Mariyam Murtaza
- The Eskitis Institute for Drug Discovery, Griffith University, Brisbane, QLD, Australia
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40
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Aghamaleky Sarvestany A, Hunter G, Tavendale A, Lamont DJ, Llavero Hurtado M, Graham LC, Wishart TM, Gillingwater TH. Label-free quantitative proteomic profiling identifies disruption of ubiquitin homeostasis as a key driver of Schwann cell defects in spinal muscular atrophy. J Proteome Res 2014; 13:4546-57. [PMID: 25151848 DOI: 10.1021/pr500492j] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Low levels of survival of motor neuron (SMN) protein cause the neuromuscular disease spinal muscular atrophy (SMA), characterized by degeneration of lower motor neurons and atrophy of skeletal muscle. Recent work demonstrated that low levels of SMN also trigger pathological changes in Schwann cells, leading to abnormal axon myelination and disrupted deposition of extracellular matrix proteins in peripheral nerve. However, the molecular pathways linking SMN depletion to intrinsic defects in Schwann cells remained unclear. Label-free proteomics analysis of Schwann cells isolated from SMA mouse peripheral nerve revealed widespread changes to the Schwann cell proteome, including disruption to growth/proliferation, cell death/survival, and molecular transport pathways. Functional clustering analyses revealed significant disruption to a number of proteins contributing to ubiquitination pathways, including reduced levels of ubiquitin-like modifier activating enzyme 1 (Uba1). Pharmacological suppression of Uba1 in Schwann cells was sufficient to reproduce the defective myelination phenotype seen in SMA. These findings demonstrate an important role for SMN protein and ubiquitin-dependent pathways in maintaining Schwann cell homeostasis and provide significant additional experimental evidence supporting a key role for ubiquitin pathways and, Uba1 in particular, in driving SMA pathogenesis across a broad range of cells and tissues.
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Affiliation(s)
- Arwin Aghamaleky Sarvestany
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh , Edinburgh EH8 9XD, United Kingdom
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Böhm S, Bernstein KA. The role of post-translational modifications in fine-tuning BLM helicase function during DNA repair. DNA Repair (Amst) 2014; 22:123-32. [PMID: 25150915 DOI: 10.1016/j.dnarep.2014.07.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Accepted: 07/14/2014] [Indexed: 12/12/2022]
Abstract
RecQ-like helicases are a highly conserved family of proteins which are critical for preserving genome integrity. Genome instability is considered a hallmark of cancer and mutations within three of the five human RECQ genes cause hereditary syndromes that are associated with cancer predisposition. The human RecQ-like helicase BLM has a central role in DNA damage signaling, repair, replication, and telomere maintenance. BLM and its budding yeast orthologue Sgs1 unwind double-stranded DNA intermediates. Intriguingly, BLM functions in both a pro- and anti-recombinogenic manner upon replicative damage, acting on similar substrates. Thus, BLM activity must be intricately controlled to prevent illegitimate recombination events that could have detrimental effects on genome integrity. In recent years it has become evident that post-translational modifications (PTMs) of BLM allow a fine-tuning of its function. To date, BLM phosphorylation, ubiquitination, and SUMOylation have been identified, in turn regulating its subcellular localization, protein-protein interactions, and protein stability. In this review, we will discuss the cellular context of when and how these different modifications of BLM occur. We will reflect on the current model of how PTMs control BLM function during DNA damage repair and compare this to what is known about post-translational regulation of the budding yeast orthologue Sgs1. Finally, we will provide an outlook toward future research, in particular to dissect the cross-talk between the individual PTMs on BLM.
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Affiliation(s)
- Stefanie Böhm
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States
| | - Kara Anne Bernstein
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States.
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42
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Therrien M, Parker JA. Worming forward: amyotrophic lateral sclerosis toxicity mechanisms and genetic interactions in Caenorhabditis elegans. Front Genet 2014; 5:85. [PMID: 24860590 PMCID: PMC4029022 DOI: 10.3389/fgene.2014.00085] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 03/30/2014] [Indexed: 12/11/2022] Open
Abstract
Neurodegenerative diseases share pathogenic mechanisms at the cellular level including protein misfolding, excitotoxicity and altered RNA homeostasis among others. Recent advances have shown that the genetic causes underlying these pathologies overlap, hinting at the existence of a genetic network for neurodegeneration. This is perhaps best illustrated by the recent discoveries of causative mutations for amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD). Once thought to be distinct entities, it is now recognized that these diseases exist along a genetic spectrum. With this wealth of discoveries comes the need to develop new genetic models of ALS and FTD to investigate not only pathogenic mechanisms linked to causative mutations, but to uncover potential genetic interactions that may point to new therapeutic targets. Given the conservation of many disease genes across evolution, Caenorhabditis elegans is an ideal system to investigate genetic interactions amongst these genes. Here we review the use of C. elegans to model ALS and investigate a putative genetic network for ALS/FTD that may extend to other neurological disorders.
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Affiliation(s)
- Martine Therrien
- Départment de Pathologie et Biologie Cellulaire, CRCHUM-Centre Hospitalier de l'Université de Montréal, Université de Montréal Montréal, QC, Canada
| | - J Alex Parker
- Départment de Pathologie et Biologie Cellulaire, Départment de Neurosciences, CRCHUM-Centre Hospitalier de l'Université de Montréal, Université de Montréal Montréal, QC, Canada
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Tseng LC, Zhang C, Cheng CM, Xu H, Hsu CH, Jiang YJ. New classes of mind bomb-interacting proteins identified from yeast two-hybrid screens. PLoS One 2014; 9:e93394. [PMID: 24714733 PMCID: PMC3979679 DOI: 10.1371/journal.pone.0093394] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 03/04/2014] [Indexed: 11/30/2022] Open
Abstract
Notch signaling pathway defines an evolutionarily conserved mechanism in cell-fate determination in a broad spectrum of developmental processes through local cell interactions. mind bomb (mib) encodes an E3 ubiquitin ligase that is involved in Notch activation through Delta ubiquitylation and internalization. To further dissect the function of Mib, two yeast two-hybrid screens for zebrafish Mib/Mib2-binding proteins with different strategies have been performed. 81 putative interesting proteins were discovered and classified into six groups: ubiquitin proteasome pathway, cytoskeleton, trafficking, replication/transcription/translation factors, cell signaling and others. Confirmed by coimmunoprecipitation (Co-IP), Mib interacted with four tested proteins: ubiquitin specific protease 1 (Usp1), ubiquitin specific protease 9 (Usp9), tumor-necrosis-factor-receptor-associated factor (TRAF)-binding domain (Trabid)/zinc finger, RAN-binding domain containing 1 (Zranb1) and hypoxia-inducible factor 1, alpha subunit inhibitor (Hif1an)/factor inhibiting HIF 1 (Fih-1). Usp1, Usp9, Trabid and Fih-1 also bound to zebrafish Mib2, a Mib homolog with similar structural domains and functions. Both Mib and Mib2 can ubiquitylate Trabid and Fih-1, indicating a potential regulating role of Mib and Mib2 on Trabid and Fih-1 and, furthermore, the possible involvement of Notch signaling in hypoxia-regulated differentiation, tumorigenesis and NF-κB pathway. Finally, functions of confirmed Mib/Mib2-interacting proteins are collated, summarized and hypothesized, which depicts a regulating network beyond Notch signaling.
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Affiliation(s)
- Li-Chuan Tseng
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan
| | - Chengjin Zhang
- Laboratory of Developmental Signalling and Patterning, Institute of Molecular and Cell Biology, Singapore, Singapore
| | - Chun-Mei Cheng
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan
| | - Haoying Xu
- Laboratory of Developmental Signalling and Patterning, Institute of Molecular and Cell Biology, Singapore, Singapore
| | - Chia-Hao Hsu
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Yun-Jin Jiang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan
- Laboratory of Developmental Signalling and Patterning, Institute of Molecular and Cell Biology, Singapore, Singapore
- Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan
- * E-mail:
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