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Chang C, Banerjee SL, Park SS, Zhang XL, Cotnoir-White D, Opperman KJ, Desbois M, Grill B, Kania A. Ubiquitin ligase and signalling hub MYCBP2 is required for efficient EPHB2 tyrosine kinase receptor function. eLife 2024; 12:RP89176. [PMID: 38289221 PMCID: PMC10945567 DOI: 10.7554/elife.89176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024] Open
Abstract
Eph receptor tyrosine kinases participate in a variety of normal and pathogenic processes during development and throughout adulthood. This versatility is likely facilitated by the ability of Eph receptors to signal through diverse cellular signalling pathways: primarily by controlling cytoskeletal dynamics, but also by regulating cellular growth, proliferation, and survival. Despite many proteins linked to these signalling pathways interacting with Eph receptors, the specific mechanisms behind such links and their coordination remain to be elucidated. In a proteomics screen for novel EPHB2 multi-effector proteins, we identified human MYC binding protein 2 (MYCBP2 or PAM or Phr1). MYCBP2 is a large signalling hub involved in diverse processes such as neuronal connectivity, synaptic growth, cell division, neuronal survival, and protein ubiquitination. Our biochemical experiments demonstrate that the formation of a complex containing EPHB2 and MYCBP2 is facilitated by FBXO45, a protein known to select substrates for MYCBP2 ubiquitin ligase activity. Formation of the MYCBP2-EPHB2 complex does not require EPHB2 tyrosine kinase activity and is destabilised by binding of ephrin-B ligands, suggesting that the MYCBP2-EPHB2 association is a prelude to EPHB2 signalling. Paradoxically, the loss of MYCBP2 results in increased ubiquitination of EPHB2 and a decrease of its protein levels suggesting that MYCBP2 stabilises EPHB2. Commensurate with this effect, our cellular experiments reveal that MYCBP2 is essential for efficient EPHB2 signalling responses in cell lines and primary neurons. Finally, our genetic studies in Caenorhabditis elegans provide in vivo evidence that the ephrin receptor VAB-1 displays genetic interactions with known MYCBP2 binding proteins. Together, our results align with the similarity of neurodevelopmental phenotypes caused by MYCBP2 and EPHB2 loss of function, and couple EPHB2 to a signalling effector that controls diverse cellular functions.
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Affiliation(s)
- Chao Chang
- Institut de recherches cliniques de Montréal (IRCM)MontréalCanada
- Integrated Program in Neuroscience, McGill UniversityMontréalCanada
| | - Sara L Banerjee
- Institut de recherches cliniques de Montréal (IRCM)MontréalCanada
- Division of Experimental Medicine, McGill UniversityMontréalCanada
| | - Sung Soon Park
- Institut de recherches cliniques de Montréal (IRCM)MontréalCanada
- Integrated Program in Neuroscience, McGill UniversityMontréalCanada
| | - Xiao Lei Zhang
- Institut de recherches cliniques de Montréal (IRCM)MontréalCanada
| | | | - Karla J Opperman
- Center for Integrative Brain Research, Seattle Children’s Research InstituteSeattleUnited States
| | - Muriel Desbois
- Center for Integrative Brain Research, Seattle Children’s Research InstituteSeattleUnited States
- School of Life Sciences, Keele UniversityKeeleUnited Kingdom
| | - Brock Grill
- Center for Integrative Brain Research, Seattle Children’s Research InstituteSeattleUnited States
- Department of Pediatrics, University of Washington School of MedicineSeattleUnited States
- Department of Pharmacology, University of Washington School of MedicineSeattleUnited States
| | - Artur Kania
- Institut de recherches cliniques de Montréal (IRCM)MontréalCanada
- Integrated Program in Neuroscience, McGill UniversityMontréalCanada
- Division of Experimental Medicine, McGill UniversityMontréalCanada
- Department of Anatomy and Cell Biology, McGill UniversityMontréalCanada
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Amezquita J, Desbois M, Opperman KJ, Pak JS, Christensen EL, Nguyen NT, Diaz-Garcia K, Borgen MA, Grill B. Axon development is regulated at genetic and proteomic interfaces between the integrin adhesome and the RPM-1 ubiquitin ligase signaling hub. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.15.566604. [PMID: 38014183 PMCID: PMC10680716 DOI: 10.1101/2023.11.15.566604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Integrin signaling plays important roles in development and disease. An adhesion signaling network called the integrin adhesome has been principally defined using bioinformatics and proteomics. To date, the adhesome has not been studied using integrated proteomic and genetic approaches. Here, proteomic studies in C. elegans identified physical associations between the RPM-1 ubiquitin ligase signaling hub and numerous adhesome components including Talin, Kindlin and beta-integrin. C. elegans RPM-1 is orthologous to human MYCBP2, a prominent player in nervous system development associated with a neurodevelopmental disorder. Using neuron-specific, CRISPR loss-of-function strategies, we show that core adhesome components affect axon development and interact genetically with RPM-1. Mechanistically, Talin opposes RPM-1 in a functional 'tug-of-war' on growth cones that is required for accurate axon termination. Thus, our findings orthogonally validate the adhesome via multi-component genetic and physical interfaces with a key neuronal signaling hub and identify new links between the adhesome and brain disorders.
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3
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Chang C, Banerjee SL, Park SS, Zhang X, Cotnoir-White D, Opperman KJ, Desbois M, Grill B, Kania A. Ubiquitin ligase and signalling hub MYCBP2 is required for efficient EPHB2 tyrosine kinase receptor function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.12.544638. [PMID: 37693478 PMCID: PMC10491099 DOI: 10.1101/2023.06.12.544638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Eph receptor tyrosine kinases participate in a variety of normal and pathogenic processes during development and throughout adulthood. This versatility is likely facilitated by the ability of Eph receptors to signal through diverse cellular signalling pathways: primarily by controlling cytoskeletal dynamics, but also by regulating cellular growth, proliferation, and survival. Despite many proteins linked to these signalling pathways interacting with Eph receptors, the specific mechanisms behind such links and their coordination remain to be elucidated. In a proteomics screen for novel EPHB2 multi-effector proteins, we identified human MYC binding protein 2 (MYCBP2 or PAM or Phr1). MYCBP2 is a large signalling hub involved in diverse processes such as neuronal connectivity, synaptic growth, cell division, neuronal survival, and protein ubiquitination. Our biochemical experiments demonstrate that the formation of a complex containing EPHB2 and MYCBP2 is facilitated by FBXO45, a protein known to select substrates for MYCBP2 ubiquitin ligase activity. Formation of the MYCBP2-EPHB2 complex does not require EPHB2 tyrosine kinase activity and is destabilised by binding of ephrin-B ligands, suggesting that the MYCBP2-EPHB2 association is a prelude to EPHB2 signalling. Paradoxically, the loss of MYCBP2 results in increased ubiquitination of EPHB2 and a decrease of its protein levels suggesting that MYCBP2 stabilises EPHB2. Commensurate with this effect, our cellular experiments reveal that MYCBP2 is essential for efficient EPHB2 signalling responses in cell lines and primary neurons. Finally, our genetic studies in C. elegans provide in vivo evidence that the ephrin receptor VAB-1 displays genetic interactions with known MYCBP2 binding proteins. Together, our results align with the similarity of neurodevelopmental phenotypes caused by MYCBP2 and EPHB2 loss of function, and couple EPHB2 to a signaling effector that controls diverse cellular functions.
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Affiliation(s)
- Chao Chang
- Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, H2W 1R7, Canada
- Integrated Program in Neuroscience, McGill University, Montréal, QC, H3A 2B4, Canada
| | - Sara L. Banerjee
- Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, H2W 1R7, Canada
- Division of Experimental Medicine, McGill University, Montréal, QC, H3A 2B2, Canada
| | - Sung Soon Park
- Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, H2W 1R7, Canada
- Integrated Program in Neuroscience, McGill University, Montréal, QC, H3A 2B4, Canada
| | - Xiaolei Zhang
- Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, H2W 1R7, Canada
| | - David Cotnoir-White
- Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, H2W 1R7, Canada
| | - Karla J. Opperman
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA 98101, USA
| | - Muriel Desbois
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA 98101, USA
- School of Life Sciences, Keele University, Keele, Staffordshire ST5 5BG, UK
| | - Brock Grill
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA 98101, USA
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA 98101, USA
- Department of Pharmacology, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Artur Kania
- Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, H2W 1R7, Canada
- Integrated Program in Neuroscience, McGill University, Montréal, QC, H3A 2B4, Canada
- Division of Experimental Medicine, McGill University, Montréal, QC, H3A 2B2, Canada
- Department of Anatomy and Cell Biology, McGill University, Montréal, QC, H3A 0C7, Canada
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4
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Navarro-Martínez A, Vicente-García C, Carvajal JJ. NMJ-related diseases beyond the congenital myasthenic syndromes. Front Cell Dev Biol 2023; 11:1216726. [PMID: 37601107 PMCID: PMC10436495 DOI: 10.3389/fcell.2023.1216726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/21/2023] [Indexed: 08/22/2023] Open
Abstract
Neuromuscular junctions (NMJs) are a special type of chemical synapse that transmits electrical stimuli from motor neurons (MNs) to their innervating skeletal muscle to induce a motor response. They are an ideal model for the study of synapses, given their manageable size and easy accessibility. Alterations in their morphology or function lead to neuromuscular disorders, such as the congenital myasthenic syndromes, which are caused by mutations in proteins located in the NMJ. In this review, we highlight novel potential candidate genes that may cause or modify NMJs-related pathologies in humans by exploring the phenotypes of hundreds of mouse models available in the literature. We also underscore the fact that NMJs may differ between species, muscles or even sexes. Hence the importance of choosing a good model organism for the study of NMJ-related diseases: only taking into account the specific features of the mammalian NMJ, experimental results would be efficiently translated to the clinic.
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Affiliation(s)
| | - Cristina Vicente-García
- Centro Andaluz de Biología del Desarrollo, CSIC-UPO-JA, Universidad Pablo de Olavide, Sevilla, Spain
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5
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Bu H, Li Z, Lu Y, Zhuang Z, Zhen Y, Zhang L. Deciphering the multifunctional role of dual leucine zipper kinase (DLK) and its therapeutic potential in disease. Eur J Med Chem 2023; 255:115404. [PMID: 37098296 DOI: 10.1016/j.ejmech.2023.115404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/19/2023] [Accepted: 04/19/2023] [Indexed: 04/27/2023]
Abstract
Dual leucine zipper kinase (DLK, MAP3K12), a serine/threonine protein kinase, plays a key role in neuronal development, as it regulates axon regeneration and degeneration through its downstream kinase. Importantly, DLK is closely related to the pathogenesis of numerous neurodegenerative diseases and the induction of β-cell apoptosis that leads to diabetes. In this review, we summarize the current understanding of DLK function, and then discuss the role of DLK signaling in human diseases. Furthermore, various types of small molecule inhibitors of DLK that have been published so far are described in detail in this paper, providing some strategies for the design of DLK small molecule inhibitors in the future.
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Affiliation(s)
- Haiqing Bu
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Zhijia Li
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Yingying Lu
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Zhiyao Zhuang
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Yongqi Zhen
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Lan Zhang
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China.
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6
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AlAbdi L, Desbois M, Rusnac DV, Sulaiman RA, Rosenfeld JA, Lalani S, Murdock DR, Burrage LC, Billie Au PY, Towner S, Wilson WG, Wong L, Brunet T, Strobl-Wildemann G, Burton JE, Hoganson G, McWalter K, Begtrup A, Zarate YA, Christensen EL, Opperman KJ, Giles AC, Helaby R, Kania A, Zheng N, Grill B, Alkuraya FS. Loss-of-function variants in MYCBP2 cause neurobehavioural phenotypes and corpus callosum defects. Brain 2023; 146:1373-1387. [PMID: 36200388 PMCID: PMC10319777 DOI: 10.1093/brain/awac364] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 08/11/2022] [Accepted: 08/22/2022] [Indexed: 11/14/2022] Open
Abstract
The corpus callosum is a bundle of axon fibres that connects the two hemispheres of the brain. Neurodevelopmental disorders that feature dysgenesis of the corpus callosum as a core phenotype offer a valuable window into pathology derived from abnormal axon development. Here, we describe a cohort of eight patients with a neurodevelopmental disorder characterized by a range of deficits including corpus callosum abnormalities, developmental delay, intellectual disability, epilepsy and autistic features. Each patient harboured a distinct de novo variant in MYCBP2, a gene encoding an atypical really interesting new gene (RING) ubiquitin ligase and signalling hub with evolutionarily conserved functions in axon development. We used CRISPR/Cas9 gene editing to introduce disease-associated variants into conserved residues in the Caenorhabditis elegans MYCBP2 orthologue, RPM-1, and evaluated functional outcomes in vivo. Consistent with variable phenotypes in patients with MYCBP2 variants, C. elegans carrying the corresponding human mutations in rpm-1 displayed axonal and behavioural abnormalities including altered habituation. Furthermore, abnormal axonal accumulation of the autophagy marker LGG-1/LC3 occurred in variants that affect RPM-1 ubiquitin ligase activity. Functional genetic outcomes from anatomical, cell biological and behavioural readouts indicate that MYCBP2 variants are likely to result in loss of function. Collectively, our results from multiple human patients and CRISPR gene editing with an in vivo animal model support a direct link between MYCBP2 and a human neurodevelopmental spectrum disorder that we term, MYCBP2-related developmental delay with corpus callosum defects (MDCD).
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Affiliation(s)
- Lama AlAbdi
- Department of Zoology, College of Science, King Saud University, Riyadh 11362, Saudi Arabia
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh 11564, Saudi Arabia
| | - Muriel Desbois
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA 98101, USA
| | - Domniţa-Valeria Rusnac
- Department of Pharmacology, University of Washington School of Medicine, Seattle, WA 98195, USA
- Howard Hughes Medical Institute, Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Raashda A Sulaiman
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh 11564, Saudi Arabia
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Seema Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - David R Murdock
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lindsay C Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Ping Yee Billie Au
- Department of Medical Genetics, Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Shelley Towner
- Pediatric Genetics, University of Virginia, Charlottesville, VA 22903, USA
| | - William G Wilson
- Pediatric Genetics, University of Virginia, Charlottesville, VA 22903, USA
| | - Lawrence Wong
- Department of Genetics, Northern California Kaiser Permanente, Oakland, CA 94611, USA
| | - Theresa Brunet
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, 81675 Munich, Germany
- Institute of Neurogenomics (ING), Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | | | - Jennifer E Burton
- Department of Genetics, University of Illinois College of Medicine at Peoria, Peoria, IL 61605, USA
| | - George Hoganson
- Department of Genetics, University of Illinois College of Medicine at Peoria, Peoria, IL 61605, USA
| | - Kirsty McWalter
- Genedx, Inc., 207 Perry Parkway, Gaithersburg, MD 20877, USA
| | - Amber Begtrup
- Genedx, Inc., 207 Perry Parkway, Gaithersburg, MD 20877, USA
| | - Yuri A Zarate
- Section of Genetics and Metabolism, Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA
| | - Elyse L Christensen
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA 98101, USA
| | - Karla J Opperman
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA 98101, USA
| | - Andrew C Giles
- Division of Medical Sciences, University of Northern British Columbia, Prince George, BC V2N 4Z9, Canada
| | - Rana Helaby
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh 11564, Saudi Arabia
| | - Artur Kania
- Institut de recherches cliniques de Montréal (IRCM), Montréal, QC H2W 1R7, Canada
- Integrated Program in Neuroscience, McGill University, Montréal, QC H3A 2B4, Canada
- Division of Experimental Medicine, McGill University, Montréal, QC H3A 2B2, Canada
- Department of Anatomy and Cell Biology, McGill University, Montréal, QC H3A 0C7, Canada
| | - Ning Zheng
- Department of Pharmacology, University of Washington School of Medicine, Seattle, WA 98195, USA
- Howard Hughes Medical Institute, Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Brock Grill
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA 98101, USA
- Department of Pharmacology, University of Washington School of Medicine, Seattle, WA 98195, USA
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA 98101, USA
| | - Fowzan S Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh 11564, Saudi Arabia
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Lépine S, Castellanos-Montiel MJ, Durcan TM. TDP-43 dysregulation and neuromuscular junction disruption in amyotrophic lateral sclerosis. Transl Neurodegener 2022; 11:56. [PMID: 36575535 PMCID: PMC9793560 DOI: 10.1186/s40035-022-00331-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 11/29/2022] [Indexed: 12/28/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a disease characterized by upper and lower motor neuron (MN) loss with a signature feature of cytoplasmic aggregates containing TDP-43, which are detected in nearly all patients. Mutations in the gene that encodes TDP-43 (TARBDP) are known to result in both familial and sporadic ALS. In ALS, disruption of neuromuscular junctions (NMJs) constitutes a critical event in disease pathogenesis, leading to denervation atrophy, motor impairments and disability. Morphological defects and impaired synaptic transmission at NMJs have been reported in several TDP-43 animal models and in vitro, linking TDP-43 dysregulation to the loss of NMJ integrity in ALS. Through the lens of the dying-back and dying-forward hypotheses of ALS, this review discusses the roles of TDP-43 related to synaptic function, with a focus on the potential molecular mechanisms occurring within MNs, skeletal muscles and glial cells that may contribute to NMJ disruption in ALS.
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Affiliation(s)
- Sarah Lépine
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada ,grid.14709.3b0000 0004 1936 8649Faculty of Medicine and Health Sciences, McGill University, 3605 De La Montagne, Montreal, QC H3G 2M1 Canada
| | - Maria José Castellanos-Montiel
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada
| | - Thomas Martin Durcan
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada
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8
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Virdee S. An atypical ubiquitin ligase at the heart of neural development and programmed axon degeneration. Neural Regen Res 2022; 17:2347-2350. [PMID: 35535869 PMCID: PMC9120709 DOI: 10.4103/1673-5374.338992] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The degeneration of nerve fibres following injury was first described by Augustus Waller over 170 years ago. Initially assumed to be a passive process, it is now evident that axons respond to insult via regulated cellular signaling events resulting in their programmed degeneration. Pro-survival and pro-degenerative factors have been identified and their regulatory mechanisms are beginning to emerge. The ubiquitin system has been implicated in the pro-degenerative process and a key component is the ubiquitin E3 ligase MYCBP2 (also known as PHR1). Ubiquitin E3 ligases are tasked with the transfer of the small protein modifier ubiquitin to substrates and consist of hundreds of members. They can be classified as single subunit systems or as multi-subunit complexes. Their catalytic domains can also be assigned to three general architectures. Hints that MYCBP2 might not conform to these established formats came to light and it is now clear from biochemical and structural studies that MYCBP2 is indeed an outlier in terms of its modus operandi. Furthermore, the unconventional way in which MYCBP2 transfers ubiquitin to substrates has been linked to neurodevelopmental and pro-degenerative function. Herein, we will summarize these research developments relating to the unusual features of MYCBP2 and postulate therapeutic strategies that prevent Wallerian degeneration. These have exciting potential for providing relief from pathological neuropathies and neurodegenerative diseases.
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Affiliation(s)
- Satpal Virdee
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Scotland, UK
- Correspondence to: Satpal Virdee, .
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9
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Goel M, Aponte AM, Wistow G, Badea TC. Molecular studies into cell biological role of Copine-4 in Retinal Ganglion Cells. PLoS One 2021; 16:e0255860. [PMID: 34847148 PMCID: PMC8631636 DOI: 10.1371/journal.pone.0255860] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 11/12/2021] [Indexed: 11/19/2022] Open
Abstract
The molecular mechanisms underlying morphological diversity in retinal cell types are poorly understood. We have previously reported that several members of the Copine family of Ca-dependent membrane adaptors are expressed in Retinal Ganglion Cells and transcriptionally regulated by Brn3 transcription factors. Several Copines are enriched in the retina and their over-expression leads to morphological changes -formation of elongated processes-, reminiscent of neurites, in HEK293 cells. However, the role of Copines in the retina is largely unknown. We now investigate Cpne4, a Copine whose expression is restricted to Retinal Ganglion Cells. Over-expression of Cpne4 in RGCs in vivo led to formation of large varicosities on the dendrites but did not otherwise visibly affect dendrite or axon formation. Protein interactions studies using yeast two hybrid analysis from whole retina cDNA revealed two Cpne4 interacting proteins-Host Cell Factor 1 and Morn2. Mass Spectrometry analysis of retina lysate pulled down using Cpne4 or its vonWillebrand A domain showed 207 interacting proteins. A Gene Ontology analysis of the discovered proteins suggests that Cpne4 is involved in several metabolic and signaling pathways in the retina.
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Affiliation(s)
- Manvi Goel
- Retinal Circuit Development & Genetics Unit, Neurobiology Neurodegeneration & Repair Laboratory, NEI, National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Angel M. Aponte
- Proteomics Core, NHLBI, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Graeme Wistow
- Section on Molecular Structure and Functional Genomics, NEI, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Tudor C. Badea
- Retinal Circuit Development & Genetics Unit, Neurobiology Neurodegeneration & Repair Laboratory, NEI, National Institutes of Health, Bethesda, Maryland, United States of America
- Faculty of Medicine, Research and Development Institute, Transilvania University of Brasov, Brasov, Romania
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10
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Mathien S, Tesnière C, Meloche S. Regulation of Mitogen-Activated Protein Kinase Signaling Pathways by the Ubiquitin-Proteasome System and Its Pharmacological Potential. Pharmacol Rev 2021; 73:263-296. [PMID: 34732541 DOI: 10.1124/pharmrev.120.000170] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mitogen-activated protein kinase (MAPK) cascades are evolutionarily conserved signaling pathways that play essential roles in transducing extracellular environmental signals into diverse cellular responses to maintain homeostasis. These pathways are classically organized into an architecture of three sequentially acting protein kinases: a MAPK kinase kinase that phosphorylates and activates a MAPK kinase, which in turn phosphorylates and activates the effector MAPK. The activity of MAPKs is tightly regulated by phosphorylation of their activation loop, which can be modulated by positive and negative feedback mechanisms to control the amplitude and duration of the signal. The signaling outcomes of MAPK pathways are further regulated by interactions of MAPKs with scaffolding and regulatory proteins. Accumulating evidence indicates that, in addition to these mechanisms, MAPK signaling is commonly regulated by ubiquitin-proteasome system (UPS)-mediated control of the stability and abundance of MAPK pathway components. Notably, the biologic activity of some MAPKs appears to be regulated mainly at the level of protein turnover. Recent studies have started to explore the potential of targeted protein degradation as a powerful strategy to investigate the biologic functions of individual MAPK pathway components and as a new therapeutic approach to overcome resistance to current small-molecule kinase inhibitors. Here, we comprehensively review the mechanisms, physiologic importance, and pharmacological potential of UPS-mediated protein degradation in the control of MAPK signaling. SIGNIFICANCE STATEMENT: Accumulating evidence highlights the importance of targeted protein degradation by the ubiquitin-proteasome system in regulating and fine-tuning the signaling output of mitogen-activated protein kinase (MAPK) pathways. Manipulating protein levels of MAPK cascade components may provide a novel approach for the development of selective pharmacological tools and therapeutics.
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Affiliation(s)
- Simon Mathien
- Institute for Research in Immunology and Cancer, Montreal, Quebec, Canada (S.Ma., C.T., S.Me.); and Molecular Biology Program, Faculty of Medicine (C.T., S.Me.) and Department of Pharmacology and Physiology (S.Me.), Université de Montréal, Montreal, Quebec, Canada
| | - Chloé Tesnière
- Institute for Research in Immunology and Cancer, Montreal, Quebec, Canada (S.Ma., C.T., S.Me.); and Molecular Biology Program, Faculty of Medicine (C.T., S.Me.) and Department of Pharmacology and Physiology (S.Me.), Université de Montréal, Montreal, Quebec, Canada
| | - Sylvain Meloche
- Institute for Research in Immunology and Cancer, Montreal, Quebec, Canada (S.Ma., C.T., S.Me.); and Molecular Biology Program, Faculty of Medicine (C.T., S.Me.) and Department of Pharmacology and Physiology (S.Me.), Université de Montréal, Montreal, Quebec, Canada
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11
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Historical perspective and progress on protein ubiquitination at glutamatergic synapses. Neuropharmacology 2021; 196:108690. [PMID: 34197891 DOI: 10.1016/j.neuropharm.2021.108690] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 06/07/2021] [Accepted: 06/22/2021] [Indexed: 12/23/2022]
Abstract
Transcription-translation coupling leads to the production of proteins that are key for controlling essential neuronal processes that include neuronal development and changes in synaptic strength. Although these events have been a prevailing theme in neuroscience, the regulation of proteins via posttranslational signaling pathways are equally relevant for these neuronal processes. Ubiquitin is one type of posttranslational modification that covalently attaches to its targets/substrates. Ubiquitination of proteins play a key role in multiple signaling pathways, the predominant being removal of its substrates by a large molecular machine called the proteasome. Here, I review 40 years of progress on ubiquitination in the nervous system at glutamatergic synapses focusing on axon pathfinding, synapse formation, presynaptic release, dendritic spine formation, and regulation of postsynaptic glutamate receptors. Finally, I elucidate emerging themes in ubiquitin biology that may challenge our current understanding of ubiquitin signaling in the nervous system.
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12
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Qin J, Wang M, Zhao T, Xiao X, Li X, Yang J, Yi L, Goffinet AM, Qu Y, Zhou L. Early Forebrain Neurons and Scaffold Fibers in Human Embryos. Cereb Cortex 2021; 30:913-928. [PMID: 31298263 DOI: 10.1093/cercor/bhz136] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 05/21/2019] [Accepted: 05/31/2019] [Indexed: 12/24/2022] Open
Abstract
Neural progenitor proliferation, neuronal migration, areal organization, and pioneer axon wiring are critical events during early forebrain development, yet remain incompletely understood, especially in human. Here, we studied forebrain development in human embryos aged 5 to 8 postconceptional weeks (WPC5-8), stages that correspond to the neuroepithelium/early marginal zone (WPC5), telencephalic preplate (WPC6 & 7), and incipient cortical plate (WPC8). We show that early telencephalic neurons are formed at the neuroepithelial stage; the most precocious ones originate from local telencephalic neuroepithelium and possibly from the olfactory placode. At the preplate stage, forebrain organization is quite similar in human and mouse in terms of areal organization and of differentiation of Cajal-Retzius cells, pioneer neurons, and axons. Like in mice, axons from pioneer neurons in prethalamus, ventral telencephalon, and cortical preplate cross the diencephalon-telencephalon junction and the pallial-subpallial boundary, forming scaffolds that could guide thalamic and cortical axons at later stages. In accord with this model, at the early cortical plate stage, corticofugal axons run in ventral telencephalon in close contact with scaffold neurons, which express CELSR3 and FZD3, two molecules that regulates formation of similar scaffolds in mice.
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Affiliation(s)
- Jingwen Qin
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory Jinan University Guangzhou, P R China
| | - Meizhi Wang
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory Jinan University Guangzhou, P R China
| | - Tianyun Zhao
- Department of Anesthesiology, Guangzhou Women and Children's Medical Center Guangzhou Medical University Guangzhou, P R China
| | - Xue Xiao
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory Jinan University Guangzhou, P R China
| | - Xuejun Li
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory Jinan University Guangzhou, P R China
| | - Jieping Yang
- Department of Obstetrics and Gynecology, Guangzhou Women and Children's Medical Center Guangzhou Medical University Guangzhou, P R China
| | - Lisha Yi
- Department of Obstetrics and Gynecology, Guangzhou Women and Children's Medical Center Guangzhou Medical University Guangzhou, P R China
| | - Andre M Goffinet
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory Jinan University Guangzhou, P R China
| | - Yibo Qu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory Jinan University Guangzhou, P R China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou, P R China
| | - Libing Zhou
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory Jinan University Guangzhou, P R China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou, P R China.,Key Laboratory of Neuroscience, School of Basic Medical Sciences; Institute of Neuroscience, The Second Affiliated Hospital Guangzhou Medical University Guangzhou, P R China
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13
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Pinto MJ, Tomé D, Almeida RD. The Ubiquitinated Axon: Local Control of Axon Development and Function by Ubiquitin. J Neurosci 2021; 41:2796-2813. [PMID: 33789876 PMCID: PMC8018891 DOI: 10.1523/jneurosci.2251-20.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 01/15/2021] [Accepted: 01/22/2021] [Indexed: 02/01/2023] Open
Abstract
Ubiquitin tagging sets protein fate. With a wide range of possible patterns and reversibility, ubiquitination can assume many shapes to meet specific demands of a particular cell across time and space. In neurons, unique cells with functionally distinct axons and dendrites harboring dynamic synapses, the ubiquitin code is exploited at the height of its power. Indeed, wide expression of ubiquitination and proteasome machinery at synapses, a diverse brain ubiquitome, and the existence of ubiquitin-related neurodevelopmental diseases support a fundamental role of ubiquitin signaling in the developing and mature brain. While special attention has been given to dendritic ubiquitin-dependent control, how axonal biology is governed by this small but versatile molecule has been considerably less discussed. Herein, we set out to explore the ubiquitin-mediated spatiotemporal control of an axon's lifetime: from its differentiation and growth through presynaptic formation, function, and pruning.
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Affiliation(s)
- Maria J Pinto
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, 3004-504, Portugal
| | - Diogo Tomé
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, 3004-504, Portugal
- Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Aveiro, 3810-193, Portugal
| | - Ramiro D Almeida
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, 3004-504, Portugal
- Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Aveiro, 3810-193, Portugal
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14
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Lee B, Cho Y. Experimental Model Systems for Understanding Human Axonal Injury Responses. Int J Mol Sci 2021; 22:E474. [PMID: 33418850 PMCID: PMC7824864 DOI: 10.3390/ijms22020474] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/03/2020] [Accepted: 12/30/2020] [Indexed: 12/26/2022] Open
Abstract
Neurons are structurally unique and have dendrites and axons that are vulnerable to injury. Some neurons in the peripheral nervous system (PNS) can regenerate their axons after injuries. However, most neurons in the central nervous system (CNS) fail to do so, resulting in irreversible neurological disorders. To understand the mechanisms of axon regeneration, various experimental models have been utilized in vivo and in vitro. Here, we collate the key experimental models that revealed the important mechanisms regulating axon regeneration and degeneration in different systems. We also discuss the advantages of experimenting with the rodent model, considering the application of these findings in understanding human diseases and for developing therapeutic methods.
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Affiliation(s)
| | - Yongcheol Cho
- Laboratory of Axon Regeneration & Degeneration, Department of Life Sciences, Korea University, Anam-ro 145, Seongbuk-gu, Seoul 02841, Korea;
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15
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Structural basis for RING-Cys-Relay E3 ligase activity and its role in axon integrity. Nat Chem Biol 2020; 16:1227-1236. [PMID: 32747811 PMCID: PMC7610530 DOI: 10.1038/s41589-020-0598-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 05/26/2020] [Accepted: 06/22/2020] [Indexed: 02/05/2023]
Abstract
MYCBP2 is a ubiquitin (Ub) E3 ligase (E3) that is essential for neurodevelopment and regulates axon maintenance. MYCBP2 transfers Ub to non-lysine substrates via a newly discovered RING-Cys-Relay (RCR) mechanism where Ub is relayed from an upstream cysteine to a downstream substrate esterification site. The molecular bases for E2-E3 Ub transfer and Ub relay are unknown. Whether these activities are linked to the neural phenotypes is also unclear. We describe the crystal structure of a covalently trapped E2-Ub:MYCBP2 transfer intermediate revealing key structural rearrangements upon E2-E3 Ub transfer and Ub relay. Our data suggest that transfer to the dynamic upstream cysteine, whilst mitigating lysine activity, requires a closed-like E2-Ub conjugate with tempered reactivity, and Ub relay is facilitated by a helix-coil transition. Furthermore, neurodevelopmental defects and delayed injury-induced degeneration in RCR-defective knock-in mice suggest its requirement, and that of substrate esterification activity, for normal neural development and programmed axon degeneration.
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16
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Jin Y, Zheng B. Multitasking: Dual Leucine Zipper-Bearing Kinases in Neuronal Development and Stress Management. Annu Rev Cell Dev Biol 2020; 35:501-521. [PMID: 31590586 DOI: 10.1146/annurev-cellbio-100617-062644] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The dual leucine zipper-bearing kinase (DLK) and leucine zipper-bearing kinase (LZK) are evolutionarily conserved MAPKKKs of the mixed-lineage kinase family. Acting upstream of stress-responsive JNK and p38 MAP kinases, DLK and LZK have emerged as central players in neuronal responses to a variety of acute and traumatic injuries. Recent studies also implicate their function in astrocytes, microglia, and other nonneuronal cells, reflecting their expanding roles in the multicellular response to injury and in disease. Of particular note is the potential link of these kinases to neurodegenerative diseases and cancer. It is thus critical to understand the physiological contexts under which these kinases are activated, as well as the signal transduction mechanisms that mediate specific functional outcomes. In this review we first provide a historical overview of the biochemical and functional dissection of these kinases. We then discuss recent findings on regulating their activity to enhance cellular protection following injury and in disease, focusing on but not limited to the nervous system.
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Affiliation(s)
- Yishi Jin
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, USA; .,Department of Neurosciences, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA;
| | - Binhai Zheng
- Department of Neurosciences, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA; .,VA San Diego Healthcare System, San Diego, California 92161, USA
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17
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Baloghova N, Lidak T, Cermak L. Ubiquitin Ligases Involved in the Regulation of Wnt, TGF-β, and Notch Signaling Pathways and Their Roles in Mouse Development and Homeostasis. Genes (Basel) 2019; 10:genes10100815. [PMID: 31623112 PMCID: PMC6826584 DOI: 10.3390/genes10100815] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 10/02/2019] [Accepted: 10/13/2019] [Indexed: 12/20/2022] Open
Abstract
The Wnt, TGF-β, and Notch signaling pathways are essential for the regulation of cellular polarity, differentiation, proliferation, and migration. Differential activation and mutual crosstalk of these pathways during animal development are crucial instructive forces in the initiation of the body axis and the development of organs and tissues. Due to the ability to initiate cell proliferation, these pathways are vulnerable to somatic mutations selectively producing cells, which ultimately slip through cellular and organismal checkpoints and develop into cancer. The architecture of the Wnt, TGF-β, and Notch signaling pathways is simple. The transmembrane receptor, activated by the extracellular stimulus, induces nuclear translocation of the transcription factor, which subsequently changes the expression of target genes. Nevertheless, these pathways are regulated by a myriad of factors involved in various feedback mechanisms or crosstalk. The most prominent group of regulators is the ubiquitin-proteasome system (UPS). To open the door to UPS-based therapeutic manipulations, a thorough understanding of these regulations at a molecular level and rigorous confirmation in vivo are required. In this quest, mouse models are exceptional and, thanks to the progress in genetic engineering, also an accessible tool. Here, we reviewed the current understanding of how the UPS regulates the Wnt, TGF-β, and Notch pathways and we summarized the knowledge gained from related mouse models.
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Affiliation(s)
- Nikol Baloghova
- Laboratory of Cancer Biology, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 252 42 Vestec, Czech Republic.
| | - Tomas Lidak
- Laboratory of Cancer Biology, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 252 42 Vestec, Czech Republic.
| | - Lukas Cermak
- Laboratory of Cancer Biology, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 252 42 Vestec, Czech Republic.
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18
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Hendi A, Kurashina M, Mizumoto K. Intrinsic and extrinsic mechanisms of synapse formation and specificity in C. elegans. Cell Mol Life Sci 2019; 76:2719-2738. [PMID: 31037336 PMCID: PMC11105629 DOI: 10.1007/s00018-019-03109-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/11/2019] [Accepted: 04/15/2019] [Indexed: 12/18/2022]
Abstract
Precise neuronal wiring is critical for the function of the nervous system and is ultimately determined at the level of individual synapses. Neurons integrate various intrinsic and extrinsic cues to form synapses onto their correct targets in a stereotyped manner. In the past decades, the nervous system of nematode (Caenorhabditis elegans) has provided the genetic platform to reveal the genetic and molecular mechanisms of synapse formation and specificity. In this review, we will summarize the recent discoveries in synapse formation and specificity in C. elegans.
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Affiliation(s)
- Ardalan Hendi
- Department of Zoology, The University of British Columbia, 2406-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Mizuki Kurashina
- Department of Zoology, The University of British Columbia, 2406-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Kota Mizumoto
- Department of Zoology, The University of British Columbia, 2406-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
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19
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Bremer J, Marsden KC, Miller A, Granato M. The ubiquitin ligase PHR promotes directional regrowth of spinal zebrafish axons. Commun Biol 2019; 2:195. [PMID: 31149640 PMCID: PMC6531543 DOI: 10.1038/s42003-019-0434-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/16/2019] [Indexed: 01/05/2023] Open
Abstract
To reconnect with their synaptic targets, severed axons need to regrow robustly and directionally along the pre-lesional trajectory. While mechanisms directing axonal regrowth are poorly understood, several proteins direct developmental axon outgrowth, including the ubiquitin ligase PHR (Mycbp2). Invertebrate PHR also limits regrowth of injured axons, whereas its role in vertebrate axonal regrowth remains elusive. Here we took advantage of the high regrowth capacity of spinal zebrafish axons and observed robust and directional regrowth following laser transection of spinal Mauthner axons. We found that PHR directs regrowing axons along the pre-lesional trajectory and across the transection site. At the transection site, initial regrowth of wild-type axons was multidirectional. Over time, misdirected sprouts were corrected in a PHR-dependent manner. Ablation of cyfip2, known to promote F-actin-polymerization and pharmacological inhibition of JNK reduced misdirected regrowth of PHR-deficient axons, suggesting that PHR controls directional Mauthner axonal regrowth through cyfip2- and JNK-dependent pathways.
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Affiliation(s)
- Juliane Bremer
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, 19104 PA USA
| | - Kurt C. Marsden
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, 19104 PA USA
- Present Address: Department of Biological Sciences, North Carolina State University, Raleigh, 27607 NC USA
| | - Adam Miller
- Institute of Neuroscience, University of Oregon, Eugene, 97405 OR USA
| | - Michael Granato
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, 19104 PA USA
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20
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Borgen MA, Giles AC, Wang D, Grill B. Synapse maintenance is impacted by ATAT-2 tubulin acetyltransferase activity and the RPM-1 signaling hub. eLife 2019; 8:44040. [PMID: 30652969 PMCID: PMC6355192 DOI: 10.7554/elife.44040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/15/2019] [Indexed: 12/16/2022] Open
Abstract
Synapse formation is comprised of target cell recognition, synapse assembly, and synapse maintenance. Maintaining established synaptic connections is essential for generating functional circuitry and synapse instability is a hallmark of neurodegenerative disease. While many molecules impact synapse formation generally, we know little about molecules that affect synapse maintenance in vivo. Using genetics and developmental time course analysis in C.elegans, we show that the α-tubulin acetyltransferase ATAT-2 and the signaling hub RPM-1 are required presynaptically to maintain stable synapses. Importantly, the enzymatic acetyltransferase activity of ATAT-2 is required for synapse maintenance. Our analysis revealed that RPM-1 is a hub in a genetic network composed of ATAT-2, PTRN-1 and DLK-1. In this network, ATAT-2 functions independent of the DLK-1 MAPK and likely acts downstream of RPM-1. Thus, our study reveals an important role for tubulin acetyltransferase activity in presynaptic maintenance, which occurs via the RPM-1/ATAT-2 pathway.
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Affiliation(s)
- Melissa A Borgen
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
| | - Andrew C Giles
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
| | - Dandan Wang
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
| | - Brock Grill
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
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21
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Asghari Adib E, Smithson LJ, Collins CA. An axonal stress response pathway: degenerative and regenerative signaling by DLK. Curr Opin Neurobiol 2018; 53:110-119. [PMID: 30053694 DOI: 10.1016/j.conb.2018.07.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 07/02/2018] [Indexed: 02/08/2023]
Abstract
Signaling through the dual leucine zipper-bearing kinase (DLK) is required for injured neurons to initiate new axonal growth; however, activation of this kinase also leads to neuronal degeneration and death in multiple models of injury and neurodegenerative diseases. This has spurred current consideration of DLK as a candidate therapeutic target, and raises a vital question: in what context is DLK a friend or foe to neurons? Here, we review our current understanding of DLK's function and mechanisms in regulating both regenerative and degenerative responses to axonal damage and stress in the nervous system.
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Affiliation(s)
- Elham Asghari Adib
- Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Laura J Smithson
- Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Catherine A Collins
- Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA.
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22
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Desbois M, Crawley O, Evans PR, Baker ST, Masuho I, Yasuda R, Grill B. PAM forms an atypical SCF ubiquitin ligase complex that ubiquitinates and degrades NMNAT2. J Biol Chem 2018; 293:13897-13909. [PMID: 29997255 DOI: 10.1074/jbc.ra118.002176] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 06/13/2018] [Indexed: 12/20/2022] Open
Abstract
PHR (PAM/Highwire/RPM-1) proteins are conserved RING E3 ubiquitin ligases that function in developmental processes, such as axon termination and synapse formation, as well as axon degeneration. At present, our understanding of how PHR proteins form ubiquitin ligase complexes remains incomplete. Although genetic studies indicate NMNAT2 is an important mediator of PHR protein function in axon degeneration, it remains unknown how PHR proteins inhibit NMNAT2. Here, we decipher the biochemical basis for how the human PHR protein PAM, also called MYCBP2, forms a noncanonical Skp/Cullin/F-box (SCF) complex that contains the F-box protein FBXO45 and SKP1 but lacks CUL1. We show FBXO45 does not simply function in substrate recognition but is important for assembly of the PAM/FBXO45/SKP1 complex. Interestingly, we demonstrate a novel role for SKP1 as an auxiliary component of the target recognition module that enhances binding of FBXO45 to NMNAT2. Finally, we provide biochemical evidence that PAM polyubiquitinates NMNAT2 and regulates NMNAT2 protein stability and degradation by the proteasome.
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Affiliation(s)
- Muriel Desbois
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458 and
| | - Oliver Crawley
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458 and
| | - Paul R Evans
- the Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Scott T Baker
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458 and
| | - Ikuo Masuho
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458 and
| | - Ryohei Yasuda
- the Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Brock Grill
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458 and
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23
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Crawley O, Giles AC, Desbois M, Kashyap S, Birnbaum R, Grill B. A MIG-15/JNK-1 MAP kinase cascade opposes RPM-1 signaling in synapse formation and learning. PLoS Genet 2017; 13:e1007095. [PMID: 29228003 PMCID: PMC5754208 DOI: 10.1371/journal.pgen.1007095] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 01/04/2018] [Accepted: 11/01/2017] [Indexed: 12/18/2022] Open
Abstract
The Pam/Highwire/RPM-1 (PHR) proteins are conserved intracellular signaling hubs that regulate synapse formation and axon termination. The C. elegans PHR protein, called RPM-1, acts as a ubiquitin ligase to inhibit the DLK-1 and MLK-1 MAP kinase pathways. We have identified several kinases that are likely to form a new MAP kinase pathway that suppresses synapse formation defects, but not axon termination defects, in the mechanosensory neurons of rpm-1 mutants. This pathway includes: MIG-15 (MAP4K), NSY-1 (MAP3K), JKK-1 (MAP2K) and JNK-1 (MAPK). Transgenic overexpression of kinases in the MIG-15/JNK-1 pathway is sufficient to impair synapse formation in wild-type animals. The MIG-15/JNK-1 pathway functions cell autonomously in the mechanosensory neurons, and these kinases localize to presynaptic terminals providing further evidence of a role in synapse development. Loss of MIG-15/JNK-1 signaling also suppresses defects in habituation to repeated mechanical stimuli in rpm-1 mutants, a behavioral deficit that is likely to arise from impaired glutamatergic synapse formation. Interestingly, habituation results are consistent with the MIG-15/JNK-1 pathway functioning as a parallel opposing pathway to RPM-1. These findings indicate the MIG-15/JNK-1 pathway can restrict both glutamatergic synapse formation and short-term learning.
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Affiliation(s)
- Oliver Crawley
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, United States of America
| | - Andrew C. Giles
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, United States of America
| | - Muriel Desbois
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, United States of America
| | - Sudhanva Kashyap
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, United States of America
| | - Rayna Birnbaum
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL, United States of America
| | - Brock Grill
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, United States of America
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24
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Diao Y, Chen Y, Zhang P, Cui L, Zhang J. Molecular guidance cues in the development of visual pathway. Protein Cell 2017; 9:909-929. [PMID: 29181831 PMCID: PMC6208478 DOI: 10.1007/s13238-017-0490-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 10/30/2017] [Indexed: 01/23/2023] Open
Abstract
70%–80% of our sensory input comes from vision. Light hit the retina at the back of our eyes and the visual information is relayed into the dorsal lateral geniculate nuclei (dLGN) and primary visual cortex (V1) thereafter, constituting the image-forming visual circuit. Molecular cues are one of the key factors to guide the wiring and refinement of the image-forming visual circuit during pre- and post-embryonic stages. Distinct molecular cues are involved in different developmental stages and nucleus, suggesting diverse guidance mechanisms. In this review, we summarize molecular guidance cues throughout the image-forming visual circuit, including chiasm determination, eye-specific segregation and refinement in the dLGN, and at last the reciprocal connections between the dLGN and V1.
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Affiliation(s)
- Yupu Diao
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Yuqing Chen
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Peijun Zhang
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, 200031, China
| | - Liyuan Cui
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Jiayi Zhang
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China.
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Pierre S, Zhang DD, Suo J, Kern K, Tarighi N, Scholich K. Myc binding protein 2 suppresses M2-like phenotypes in macrophages during zymosan-induced inflammation in mice. Eur J Immunol 2017; 48:239-249. [PMID: 29067676 DOI: 10.1002/eji.201747129] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 09/09/2017] [Accepted: 10/17/2017] [Indexed: 02/03/2023]
Abstract
MYCBP2 is an E3 ubiquitin ligase, which is well characterized as a key element in the inhibition of neuronal growth, synapse formation and synaptic strength by regulating several signaling pathways. Although MYCBP2 was suspected to be expressed also in immune cells, to date nothing is known about its role in inflammation. We used Multi-epitope ligand cartography (MELC), a method for multiple sequential immunohistology, to show that MYCBP2 is strongly expressed in monocyte-derived macrophages during zymosan-induced inflammation. We generated a myeloid-specific knockout mouse and found that loss of MYCBP2 in myeloid cells reduced nociceptive (painful) behavior during the resolution phase (1-3 days after zymosan injection). Quantitative MELC analyses and flow cytometric analysis showed an increased number of CD206-expressing macrophages in the inflamed paw tissue. Fittingly, CD206 and arginase 1 expression was upregulated in MYCBP2-deficient bone marrow-derived macrophages after polarization with IL10 or IL4. The regulation of protein expression in these macrophages by MYCBP2 varied depending on the polarization signal. The increased IL10-induced CD206 expression in MYCBP2-deficient macrophages was mediated by p38 MAPK, while IL4-induced CD206 expression in MYCBP2-deficient macrophages was mediated by protein kinase A.
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Affiliation(s)
- Sandra Pierre
- Institut für Klinische Pharmakologie, Uniklinikum Frankfurt, Germany
| | - Dong Dong Zhang
- Institut für Klinische Pharmakologie, Uniklinikum Frankfurt, Germany
| | - Jing Suo
- Institut für Klinische Pharmakologie, Uniklinikum Frankfurt, Germany
| | - Katharina Kern
- Institut für Klinische Pharmakologie, Uniklinikum Frankfurt, Germany
| | - Neda Tarighi
- Institut für Klinische Pharmakologie, Uniklinikum Frankfurt, Germany
| | - Klaus Scholich
- Institut für Klinische Pharmakologie, Uniklinikum Frankfurt, Germany
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26
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Seven pass Cadherins CELSR1-3. Semin Cell Dev Biol 2017; 69:102-110. [PMID: 28716607 DOI: 10.1016/j.semcdb.2017.07.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/12/2017] [Accepted: 07/13/2017] [Indexed: 11/20/2022]
Abstract
Cadherin EGF LAG seven-pass G-type receptors 1, 2 and 3 (CELSR1-3) form a family of three atypical cadherins with multiple functions in epithelia and in the nervous system. During the past decade, evidence has accumulated for a key role of CELSR1 in epithelial planar cell polarity (PCP), and for CELSR2 and CELSR3 in ciliogenesis and neural development, especially neuron migration and axon guidance in the central, peripheral and enteric nervous systems. Phenotypes in mutant mice indicate that CELSR proteins work in concert with FZD3 and FZD6, but several questions remain. Apart from PCP signaling pathways implicating CELSR1 that begin to be unraveled, little is known about other signals generated by CELSR2 and CELSR3. A crucial question concerns the putative ligands that trigger signaling, in particular what is the role of WNT factors. Another critical issue is the identification of novel intracellular pathways and effectors that relay and transmit signals in receptive cells? Answers to those questions should further our understanding of the role of those important molecules not only in development but also in regeneration and disease.
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Yin C, Huang GF, Sun XC, Guo Z, Zhang JH. DLK silencing attenuated neuron apoptosis through JIP3/MA2K7/JNK pathway in early brain injury after SAH in rats. Neurobiol Dis 2017; 103:133-143. [PMID: 28396258 DOI: 10.1016/j.nbd.2017.04.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 03/21/2017] [Accepted: 04/05/2017] [Indexed: 01/19/2023] Open
Abstract
OBJECTIVE Dual leucine zipper kinase (DLK/MA3K12) has been reported involved in apoptosis and neuronal degeneration during neural development and traumatic brain injury. This study was designed to investigate the role of DLK with its adaptor protein JNK interacting protein-3 (JIP3), and its downstream MA2K7/JNK signaling pathway in early brain injury (EBI) after subarachnoid hemorrhage (SAH) in a rat model. DESIGN Controlled in vivo laboratory study. SETTING Animal research laboratory. SUBJECTS Two hundred and twenty-three adult male Sprague-Dawley rats weighing 280-320g. INTERVENTIONS SAH was induced by endovascular perforation in rats. The SAH grade, neurological score, and brain water content were measured at 24 and 72h after SAH. Immunofluorescence staining was used to detect the cells that expressed DLK. The terminal deoxynucleotid transferase-deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) was used to detect the neuronal apoptosis. In mechanism research, the expression of DLK, JIP3, phosphorylated-JNK (p-JNK)/JNK, and cleaved caspase-3 (CC-3) were analyzed by western blot at 24h after SAH. The DLK small interfering RNA (siRNA), JIP3 siRNA, MA2K7 siRNA and recombinant DLK protein which injected intracerebroventricularly were given as the interventions. MEASUREMENTS AND MAIN RESULTS The DLK expression was increased in the left cortex neurons and peaked at 24h after SAH. DLK siRNA attenuated brain edema, reduced neuronal apoptosis, and improved the neurobehavioral functions after SAH, but the recombinant DLK protein deteriorated neurobehavioral functions and brain edema. DLK siRNA decreased and recombinant DLK protein increased the expression of MA2K7/p-JNK/CC-3 at 24h after SAH. The JIP3 siRNA reduced the level of JIP3/MA2K7/p-JNK/CC-3, combined DLK siRNA and JIP3 siRNA further decreased the expression of DLK/MA2K7/p-JNK/CC-3, and MA2K7 siRNA lowered the amount of MA2K7/p-JNK/CC-3 at 24h after SAH. CONCLUSIONS As a negative role, DLK was involved in EBI after SAH, possibly mediated by its adaptor protein JIP3 and MA2K7/JNK signaling pathways. To reduce the level of DLK may be a new target as intervention for SAH.
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Affiliation(s)
- Cheng Yin
- Departments of Anesthesiology and Physiology, Loma Linda University School of Medicine, Loma Linda, CA, USA; Department of Neurosurgery, Affiliated Hospital of the University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, China
| | - Guang-Fu Huang
- Department of Neurosurgery, Affiliated Hospital of the University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, China
| | - Xiao-Chuan Sun
- Department of Neurosurgery, First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Zongduo Guo
- Department of Neurosurgery, First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - John H Zhang
- Departments of Anesthesiology and Physiology, Loma Linda University School of Medicine, Loma Linda, CA, USA.
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Axon Termination, Pruning, and Synaptogenesis in the Giant Fiber System of Drosophila melanogaster Is Promoted by Highwire. Genetics 2017; 205:1229-1245. [PMID: 28100586 DOI: 10.1534/genetics.116.197343] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 12/20/2016] [Indexed: 11/18/2022] Open
Abstract
The ubiquitin ligase Highwire has a conserved role in synapse formation. Here, we show that Highwire coordinates several facets of central synapse formation in the Drosophila melanogaster giant fiber system, including axon termination, axon pruning, and synaptic function. Despite the similarities to the fly neuromuscular junction, the role of Highwire and the underlying signaling pathways are distinct in the fly's giant fiber system. During development, branching of the giant fiber presynaptic terminal occurs and, normally, the transient branches are pruned away. However, in highwire mutants these ectopic branches persist, indicating that Highwire promotes axon pruning. highwire mutants also exhibit defects in synaptic function. Highwire promotes axon pruning and synaptic function cell-autonomously by attenuating a mitogen-activated protein kinase pathway including Wallenda, c-Jun N-terminal kinase/Basket, and the transcription factor Jun. We also show a novel role for Highwire in non-cell autonomous promotion of synaptic function from the midline glia. Highwire also regulates axon termination in the giant fibers, as highwire mutant axons exhibit severe overgrowth beyond the pruning defect. This excessive axon growth is increased by manipulating Fos expression in the cells surrounding the giant fiber terminal, suggesting that Fos regulates a trans-synaptic signal that promotes giant fiber axon growth.
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29
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Early Commissural Diencephalic Neurons Control Habenular Axon Extension and Targeting. Curr Biol 2017; 27:270-278. [PMID: 28065605 DOI: 10.1016/j.cub.2016.11.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 10/07/2016] [Accepted: 11/16/2016] [Indexed: 01/19/2023]
Abstract
Most neuronal populations form on both the left and right sides of the brain. Their efferent axons appear to grow synchronously along similar pathways on each side, although the neurons or their environment often differ between the two hemispheres [1-4]. How this coordination is controlled has received little attention. Frequently, neurons establish interhemispheric connections, which can function to integrate information between brain hemispheres (e.g., [5]). Such commissures form very early, suggesting their potential developmental role in coordinating ipsilateral axon navigation during embryonic development [4]. To address the temporal-spatial control of bilateral axon growth, we applied long-term time-lapse imaging to visualize the formation of the conserved left-right asymmetric habenular neural circuit in the developing zebrafish embryo [6]. Although habenular neurons are born at different times across brain hemispheres [7], we found that elongation of habenular axons occurs synchronously. The initiation of axon extension is not controlled within the habenular network itself but through an early developing proximal diencephalic network. The commissural neurons of this network influence habenular axons both ipsilaterally and contralaterally. Their unilateral absence impairs commissure formation and coordinated habenular axon elongation and causes their subsequent arrest on both sides of the brain. Thus, habenular neural circuit formation depends on a second intersecting commissural network, which facilitates the exchange of information between hemispheres required for ipsilaterally projecting habenular axons. This mechanism of network formation may well apply to other circuits, and has only remained undiscovered due to technical limitations.
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Baker ST, Grill B. Defining Minimal Binding Regions in Regulator of Presynaptic Morphology 1 (RPM-1) Using Caenorhabditis elegans Neurons Reveals Differential Signaling Complexes. J Biol Chem 2016; 292:2519-2530. [PMID: 27979965 DOI: 10.1074/jbc.m116.748004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 12/14/2016] [Indexed: 12/22/2022] Open
Abstract
The intracellular signaling protein regulator of presynaptic morphology 1 (RPM-1) is a conserved regulator of synapse formation and axon termination in Caenorhabditis elegans RPM-1 functions in a ubiquitin ligase complex with the F-box protein FSN-1 and functions through the microtubule binding protein RAE-1. Using a structure-function approach and positive selection for transgenic C. elegans, we explored the biochemical relationship between RPM-1, FSN-1, and RAE-1. This led to the identification of two new domains in RPM-1 that are sufficient for binding to FSN-1, called FSN-1 binding domain 2 (FBD2) and FBD3. Furthermore, we map the RAE-1 binding domain to a much smaller region of RPM-1. Point mutations in RPM-1 that reduce binding to RAE-1 did not affect FSN-1 binding, indicating that RPM-1 utilizes different biochemical mechanisms to bind these molecules. Analysis of RPM-1 protein complexes in the neurons of C. elegans elucidated two further discoveries: FSN-1 binds to RAE-1, and this interaction is not mediated by RPM-1, and RPM-1 binding to FSN-1 and RAE-1 reduces FSN-1·RAE-1 complex formation. These results indicate that RPM-1 uses different mechanisms to recruit FSN-1 and RAE-1 into independent signaling complexes in neurons.
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Affiliation(s)
- Scott T Baker
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458
| | - Brock Grill
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458
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31
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Dragich JM, Kuwajima T, Hirose-Ikeda M, Yoon MS, Eenjes E, Bosco JR, Fox LM, Lystad AH, Oo TF, Yarygina O, Mita T, Waguri S, Ichimura Y, Komatsu M, Simonsen A, Burke RE, Mason CA, Yamamoto A. Autophagy linked FYVE (Alfy/WDFY3) is required for establishing neuronal connectivity in the mammalian brain. eLife 2016; 5. [PMID: 27648578 PMCID: PMC5030082 DOI: 10.7554/elife.14810] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 08/25/2016] [Indexed: 12/23/2022] Open
Abstract
The regulation of protein degradation is essential for maintaining the appropriate environment to coordinate complex cell signaling events and to promote cellular remodeling. The Autophagy linked FYVE protein (Alfy), previously identified as a molecular scaffold between the ubiquitinated cargo and the autophagic machinery, is highly expressed in the developing central nervous system, indicating that this pathway may have yet unexplored roles in neurodevelopment. To examine this possibility, we used mouse genetics to eliminate Alfy expression. We report that this evolutionarily conserved protein is required for the formation of axonal tracts throughout the brain and spinal cord, including the formation of the major forebrain commissures. Consistent with a phenotype reflecting a failure in axon guidance, the loss of Alfy in mice disrupts localization of glial guidepost cells, and attenuates axon outgrowth in response to Netrin-1. These findings further support the growing indication that macroautophagy plays a key role in the developing CNS.
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Affiliation(s)
- Joanna M Dragich
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, United States
| | - Takaaki Kuwajima
- Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, United States.,Department of Cell Biology, College of Physicians and Surgeons, Columbia University, New York, United States
| | - Megumi Hirose-Ikeda
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, United States
| | - Michael S Yoon
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, United States
| | - Evelien Eenjes
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, United States
| | - Joan R Bosco
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, United States
| | - Leora M Fox
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, United States.,Doctoral Program in Neurobiology and Behavior, Columbia University, New York, United States
| | - Alf H Lystad
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Tinmarla F Oo
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, United States
| | - Olga Yarygina
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, United States
| | - Tomohiro Mita
- The Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Satoshi Waguri
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Yoshinobu Ichimura
- The Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Masaaki Komatsu
- The Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Anne Simonsen
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Robert E Burke
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, United States.,Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, United States.,Department of Cell Biology, College of Physicians and Surgeons, Columbia University, New York, United States
| | - Carol A Mason
- Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, United States.,Department of Cell Biology, College of Physicians and Surgeons, Columbia University, New York, United States.,Department of Neuroscience, College of Physicians and Surgeons, Columbia University, New York, United States.,Department of Ophthalmology, College of Physicians and Surgeons, Columbia University, New York, United States
| | - Ai Yamamoto
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, United States.,Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, United States.,Department of Cell Biology, College of Physicians and Surgeons, Columbia University, New York, United States
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32
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Blondeau A, Lucier JF, Matteau D, Dumont L, Rodrigue S, Jacques PÉ, Blouin R. Dual leucine zipper kinase regulates expression of axon guidance genes in mouse neuronal cells. Neural Dev 2016; 11:13. [PMID: 27468987 PMCID: PMC4965899 DOI: 10.1186/s13064-016-0068-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 07/25/2016] [Indexed: 11/10/2022] Open
Abstract
Background Recent genetic studies in model organisms, such as Drosophila, C. elegans and mice, have highlighted a critical role for dual leucine zipper kinase (DLK) in neural development and axonal responses to injury. However, exactly how DLK fulfills these functions remains to be determined. Using RNA-seq profiling, we evaluated the global changes in gene expression that are caused by shRNA-mediated knockdown of endogenous DLK in differentiated Neuro-2a neuroblastoma cells. Results Our analysis led to the identification of numerous up- and down-regulated genes, among which several were found to be associated with system development and axon guidance according to gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, respectively. Because of their importance in axonal growth, pruning and regeneration during development and adult life, we then examined by quantitative RT-PCR the mRNA expression levels of the identified axon guidance genes in DLK-depleted cells. Consistent with the RNA-seq data, our results confirmed that loss of DLK altered expression of the genes encoding neuropilin 1 (Nrp1), plexin A4 (Plxna4), Eph receptor A7 (Epha7), Rho family GTPase 1 (Rnd1) and semaphorin 6B (Sema6b). Interestingly, this regulation of Nrp1 and Plxna4 mRNA expression by DLK in Neuro-2a cells was also reflected at the protein level, implicating DLK in the modulation of the function of these axon guidance molecules. Conclusions Collectively, these results provide the first evidence that axon guidance genes are downstream targets of the DLK signaling pathway, which through their regulation probably modulates neuronal cell development, structure and function. Electronic supplementary material The online version of this article (doi:10.1186/s13064-016-0068-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Andréanne Blondeau
- Département de biologie, Faculté des sciences, Université de Sherbrooke, 2500 Boul. de l'Université, Sherbrooke, Québec, J1K 2R1, Canada
| | - Jean-François Lucier
- Département de biologie, Faculté des sciences, Université de Sherbrooke, 2500 Boul. de l'Université, Sherbrooke, Québec, J1K 2R1, Canada
| | - Dominick Matteau
- Département de biologie, Faculté des sciences, Université de Sherbrooke, 2500 Boul. de l'Université, Sherbrooke, Québec, J1K 2R1, Canada
| | - Lauralyne Dumont
- Département de biologie, Faculté des sciences, Université de Sherbrooke, 2500 Boul. de l'Université, Sherbrooke, Québec, J1K 2R1, Canada
| | - Sébastien Rodrigue
- Département de biologie, Faculté des sciences, Université de Sherbrooke, 2500 Boul. de l'Université, Sherbrooke, Québec, J1K 2R1, Canada
| | - Pierre-Étienne Jacques
- Département de biologie, Faculté des sciences, Université de Sherbrooke, 2500 Boul. de l'Université, Sherbrooke, Québec, J1K 2R1, Canada.,Département d'informatique, Faculté des sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Sherbrooke, Canada
| | - Richard Blouin
- Département de biologie, Faculté des sciences, Université de Sherbrooke, 2500 Boul. de l'Université, Sherbrooke, Québec, J1K 2R1, Canada.
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Feoktistov AI, Herman TG. Wallenda/DLK protein levels are temporally downregulated by Tramtrack69 to allow R7 growth cones to become stationary boutons. Development 2016; 143:2983-93. [PMID: 27402706 DOI: 10.1242/dev.134403] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 06/23/2016] [Indexed: 11/20/2022]
Abstract
Dual leucine zipper kinase (DLK) promotes growth cone motility and must be restrained to ensure normal development. PHR (Pam/Highwire/RPM-1) ubiquitin ligases therefore target DLK for degradation unless axon injury occurs. Overall DLK levels decrease during development, but how DLK levels are regulated within a developing growth cone has not been examined. We analyzed the expression of the fly DLK Wallenda (Wnd) in R7 photoreceptor growth cones as they halt at their targets and become presynaptic boutons. We found that Wnd protein levels are repressed by the PHR protein Highwire (Hiw) during R7 growth cone halting, as has been observed in other systems. However, as R7 growth cones become boutons, Wnd levels are further repressed by a temporally expressed transcription factor, Tramtrack69 (Ttk69). Previously unobserved negative feedback from JNK also contributes to Wnd repression at both time points. We conclude that neurons deploy additional mechanisms to downregulate DLK as they form stable, synaptic connections. We use live imaging to probe the effects of Wnd and Ttk69 on R7 bouton development and conclude that Ttk69 coordinates multiple regulators of this process.
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Affiliation(s)
- Alexander I Feoktistov
- Institute of Molecular Biology, Department of Biology, University of Oregon, Eugene, OR 97403, USA
| | - Tory G Herman
- Institute of Molecular Biology, Department of Biology, University of Oregon, Eugene, OR 97403, USA
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34
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Galazo MJ, Emsley JG, Macklis JD. Corticothalamic Projection Neuron Development beyond Subtype Specification: Fog2 and Intersectional Controls Regulate Intraclass Neuronal Diversity. Neuron 2016; 91:90-106. [PMID: 27321927 DOI: 10.1016/j.neuron.2016.05.024] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 03/16/2016] [Accepted: 05/16/2016] [Indexed: 01/05/2023]
Abstract
Corticothalamic projection neurons (CThPN) are a diverse set of neurons, critical for function of the neocortex. CThPN development and diversity need to be precisely regulated, but little is known about molecular controls over their differentiation and functional specialization, critically limiting understanding of cortical development and complexity. We report the identification of a set of genes that both define CThPN and likely control their differentiation, diversity, and function. We selected the CThPN-specific transcriptional coregulator Fog2 for functional analysis. We identify that Fog2 controls CThPN molecular differentiation, axonal targeting, and diversity, in part by regulating the expression level of Ctip2 by CThPN, via combinatorial interactions with other molecular controls. Loss of Fog2 specifically disrupts differentiation of subsets of CThPN specialized in motor function, indicating that Fog2 coordinates subtype and functional-area differentiation. These results confirm that we identified key controls over CThPN development and identify Fog2 as a critical control over CThPN diversity.
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Affiliation(s)
- Maria J Galazo
- Department of Stem Cell and Regenerative Biology, Center for Brain Science, and Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
| | - Jason G Emsley
- Department of Stem Cell and Regenerative Biology, Center for Brain Science, and Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
| | - Jeffrey D Macklis
- Department of Stem Cell and Regenerative Biology, Center for Brain Science, and Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA.
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Yin C, Huang GF, Sun XC, Guo Z, Zhang JH. Tozasertib attenuates neuronal apoptosis via DLK/JIP3/MA2K7/JNK pathway in early brain injury after SAH in rats. Neuropharmacology 2016; 108:316-23. [PMID: 27084696 DOI: 10.1016/j.neuropharm.2016.04.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 04/05/2016] [Accepted: 04/11/2016] [Indexed: 01/31/2023]
Abstract
BACKGROUND AND PURPOSE Since tozasertib is neuroprotective for injured optic nerve, this study is intended to test whether tozasertib reduces early brain injury after subarachnoid hemorrhage (SAH) in a rat model. METHODS Two hundred sixteen (216) male Sprague-Dawley rats were randomly subjected to endovascular perforation model of SAH and sham group. SAH grade, neurological score, and brain water content were measured at 24 and 72 h after SAH. Dual leucine zipper kinase (DLK) and its downstream factors, JNK-interacting protein 3 (JIP3), MA2K7, p-JNK/JNK (c-Jun N-terminal kinase), and apoptosis related proteins cleaved caspase-3 (CC-3), Bim, Bcl-2, and cleaved caspase-9 (CC-9) were analyzed by western blot at 24 h after SAH. Apoptotic cells were detected by terminal deoxynucleotid transferase-deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL). DLK small interfering RNA (siRNA), JIP3 siRNA and MA2K7 siRNA, the JNK, p38MAPK, and MEK inhibitors SP600125, SB203580, and PD98059 were used for intervention. RESULTS Tozasertib reduced neuronal apoptosis, attenuated brain edema and improved neurobehavioral deficits 24 and 72 h after SAH. At 24 h After SAH, DLK/JIP3/MA2K7/p-JNK/CC-3 expressions were elevated markedly and tozasertib reduced DLK, MA2K7/p-JNK/CC-3 expressions but enhanced JIP3 expression. In the presence of tozasertib, DLK/JIP3/MA2K7 siRNA and SP600125, SB203580 and PD98059 deteriorated the neurobehavioral deficits, brain edema and increased the expression of CC-3. SAH potentiated the expression of Bim, CC-9, and CC-3 but reduced Bcl-2, while tozasertib reduced expression of Bim, CC-9, and CC-3 but enhanced Bcl-2. CONCLUSIONS Tozasertib reduced neuronal apoptosis and improved outcome possibly via DLK/JIP3/MA2K7/JNK pathways after SAH.
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Affiliation(s)
- Cheng Yin
- Departments of Anesthesiology and Physiology, Loma Linda University School of Medicine, Loma Linda, CA, USA; Department of Neurosurgery, Hospital of the University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, China
| | - Guang-Fu Huang
- Department of Neurosurgery, Hospital of the University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, China
| | - Xiao-Chuan Sun
- Department of Neurosurgery, First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Zongduo Guo
- Department of Neurosurgery, First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - John H Zhang
- Departments of Anesthesiology and Physiology, Loma Linda University School of Medicine, Loma Linda, CA, USA.
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36
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Oetjen E, Lemcke T. Dual leucine zipper kinase (MAP3K12) modulators: a patent review (2010–2015). Expert Opin Ther Pat 2016; 26:607-16. [DOI: 10.1517/13543776.2016.1170810] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Wallbach M, Duque Escobar J, Babaeikelishomi R, Stahnke MJ, Blume R, Schröder S, Kruegel J, Maedler K, Kluth O, Kehlenbach RH, Miosge N, Oetjen E. Distinct functions of the dual leucine zipper kinase depending on its subcellular localization. Cell Signal 2016; 28:272-83. [PMID: 26776303 DOI: 10.1016/j.cellsig.2016.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 12/20/2015] [Accepted: 01/04/2016] [Indexed: 01/09/2023]
Abstract
The dual leucine zipper kinase DLK induces β-cell apoptosis by inhibiting the transcriptional activity conferred by the β-cell protective transcription factor cAMP response element binding protein CREB. This action might contribute to β-cell loss and ultimately diabetes. Within its kinase domain DLK shares high homology with the mixed lineage kinase (MLK) 3, which is activated by tumor necrosis factor (TNF) α and interleukin (IL)-1β, known prediabetic signals. In the present study, the regulation of DLK in β-cells by these cytokines was investigated. Both, TNFα and IL-1β induced the nuclear translocation of DLK. Mutations within a putative nuclear localization signal (NLS) prevented basal and cytokine-induced nuclear localization of DLK and binding to the importin receptor importin α, thereby demonstrating a functional NLS within DLK. DLK NLS mutants were catalytically active as they phosphorylated their down-stream kinase c-Jun N-terminal kinase to the same extent as DLK wild-type but did neither inhibit CREB-dependent gene transcription nor transcription conferred by the promoter of the anti-apoptotic protein BCL-xL. In addition, the β-cell apoptosis-inducing effect of DLK was severely diminished by mutation of its NLS. In a murine model of prediabetes, enhanced nuclear DLK was found. These data demonstrate that DLK exerts distinct functions, depending on its subcellular localization and thus provide a novel level of regulating DLK action. Furthermore, the prevention of the nuclear localization of DLK as induced by prediabetic signals with consecutive suppression of β-cell apoptosis might constitute a novel target in the therapy of diabetes mellitus.
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Affiliation(s)
- Manuel Wallbach
- Department of Pharmacology, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Jorge Duque Escobar
- Department of Clinical Pharmacology and Toxicology, University Medical Center Hamburg Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Rohollah Babaeikelishomi
- Department of Pharmacology, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany; Department of Clinical Pharmacology and Toxicology, University Medical Center Hamburg Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Marie-Jeannette Stahnke
- Department of Pharmacology, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Roland Blume
- Department of Pharmacology, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Sabine Schröder
- Department of Clinical Pharmacology and Toxicology, University Medical Center Hamburg Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Jenny Kruegel
- Department of Prothetics, Faculty of Medicine, Georg-August-University, GZMB, Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Kathrin Maedler
- Center for Biomolecular Interactions Bremen, Leobener Str. Im NW2, 28359 Bremen, Germany
| | - Oliver Kluth
- German Institute of Human Nutrition Potsdam-Rehbrücke, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
| | - Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Nicolai Miosge
- Department of Prothetics, Faculty of Medicine, Georg-August-University, GZMB, Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Elke Oetjen
- Department of Pharmacology, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany; Department of Clinical Pharmacology and Toxicology, University Medical Center Hamburg Eppendorf, Martinistr. 52, 20246 Hamburg, Germany; Institute of Pharmacy, University of Hamburg, Bundesstr. 45, 20146 Hamburg, Germany.
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Grill B, Murphey RK, Borgen MA. The PHR proteins: intracellular signaling hubs in neuronal development and axon degeneration. Neural Dev 2016; 11:8. [PMID: 27008623 PMCID: PMC4806438 DOI: 10.1186/s13064-016-0063-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/15/2016] [Indexed: 11/10/2022] Open
Abstract
During development, a coordinated and integrated series of events must be accomplished in order to generate functional neural circuits. Axons must navigate toward target cells, build synaptic connections, and terminate outgrowth. The PHR proteins (consisting of mammalian Phr1/MYCBP2, Drosophila Highwire and C. elegans RPM-1) function in each of these events in development. Here, we review PHR function across species, as well as the myriad of signaling pathways PHR proteins regulate. These findings collectively suggest that the PHR proteins are intracellular signaling hubs, a concept we explore in depth. Consistent with prominent developmental functions, genetic links have begun to emerge between PHR signaling networks and neurodevelopmental disorders, such as autism, schizophrenia and intellectual disability. Finally, we discuss the recent and important finding that PHR proteins regulate axon degeneration, which has further heightened interest in this fascinating group of molecules.
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Affiliation(s)
- Brock Grill
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL, 33458, USA.
| | - Rodney K Murphey
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, 33458, USA
| | - Melissa A Borgen
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL, 33458, USA
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Willenberg R, Steward O. Nonspecific labeling limits the utility of Cre-Lox bred CST-YFP mice for studies of corticospinal tract regeneration. J Comp Neurol 2015; 523:2665-82. [PMID: 25976033 PMCID: PMC4607560 DOI: 10.1002/cne.23809] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 05/10/2015] [Accepted: 05/12/2015] [Indexed: 12/20/2022]
Abstract
Studies of axon regeneration in the spinal cord often assess regeneration of the corticospinal tract (CST). Emx1-Cre x Thy1-STOP-YFP mice have been reported to have yellow fluorescent protein (YFP) selectively expressed in forebrain neurons leading to genetic labeling of CST axons in the spinal cord, and it was suggested that these CST-YFP mice would be useful for studies of CST regeneration. Because regeneration past a lesion may involve only a few axons, the presence of labeled non-CST axons compromises interpretation. We show here that in CST-YFP mice, some YFP-labeled axons are not from the CST. Specifically, YFP-labeled axons are present in regions beyond those with anterogradely labeled CST axons, most YFP-labeled axons beyond established CST locations do not undergo Wallerian degeneration following a large lesion of the sensorimotor cortex, some rubrospinal and reticulospinal neurons are labeled with YFP, and some YFP-labeled cells in the spinal gray matter have YFP-labeled projections into the spinal cord white matter. We further demonstrate that the density of YFP-labeled axon arbors hinders tracing of single axons to their point of origin in the main descending tracts. In light of recent advances in 3D imaging for visualizing axons in unsectioned blocks of spinal cord, we also assessed CST-YFP mice for 3D imaging and found that YFP fluorescence in CST-YFP mice is faint for clearing-based 3D imaging in comparison with fluorescence in Thy1-YFP-H mice and fluorescence of mini-ruby biotinylated dextran amine (BDA). Overall, the nonspecific and faint YFP labeling in CST-YFP mice limits their utility for assessments of CST axon regeneration.
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Affiliation(s)
- Rafer Willenberg
- Reeve-Irvine Research Center, University of California at Irvine, Irvine, California 92697
- Department of Anatomy & Neurobiology, University of California at Irvine, Irvine, California 92697
| | - Oswald Steward
- Reeve-Irvine Research Center, University of California at Irvine, Irvine, California 92697
- Department of Anatomy & Neurobiology, University of California at Irvine, Irvine, California 92697
- Department of Neurobiology & Behavior, University of California at Irvine, Irvine, California 92697
- Department of Neurosurgery, University of California at Irvine, Irvine, California 92697
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Giles AC, Opperman KJ, Rankin CH, Grill B. Developmental Function of the PHR Protein RPM-1 Is Required for Learning in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2015; 5:2745-57. [PMID: 26464359 PMCID: PMC4683646 DOI: 10.1534/g3.115.021410] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 10/06/2015] [Indexed: 12/12/2022]
Abstract
The PAM/Highwire/RPM-1 (PHR) proteins are signaling hubs that function as important regulators of neural development. Loss of function in Caenorhabditis elegans rpm-1 and Drosophila Highwire results in failed axon termination, inappropriate axon targeting, and abnormal synapse formation. Despite broad expression in the nervous system and relatively dramatic defects in synapse formation and axon development, very mild abnormalities in behavior have been found in animals lacking PHR protein function. Therefore, we hypothesized that large defects in behavior might only be detected in scenarios in which evoked, prolonged circuit function is required, or in which behavioral plasticity occurs. Using quantitative approaches in C. elegans, we found that rpm-1 loss-of-function mutants have relatively mild abnormalities in exploratory locomotion, but have large defects in evoked responses to harsh touch and learning associated with tap habituation. We explored the nature of the severe habituation defects in rpm-1 mutants further. To address what part of the habituation circuit was impaired in rpm-1 mutants, we performed rescue analysis with promoters for different neurons. Our findings indicate that RPM-1 function in the mechanosensory neurons affects habituation. Transgenic expression of RPM-1 in adult animals failed to rescue habituation defects, consistent with developmental defects in rpm-1 mutants resulting in impaired habituation. Genetic analysis showed that other regulators of neuronal development that function in the rpm-1 pathway (including glo-4, fsn-1, and dlk-1) also affected habituation. Overall, our findings suggest that developmental defects in rpm-1 mutants manifest most prominently in behaviors that require protracted or plastic circuit function, such as learning.
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Affiliation(s)
- Andrew C Giles
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458
| | - Karla J Opperman
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458
| | - Catharine H Rankin
- Department of Psychology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada Brain Research Centre, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
| | - Brock Grill
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458
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In vitro interaction between coxsackievirus B3 VP1 protein and human pleckstrin homology domain retinal protein (PHR1). Virus Genes 2015; 51:182-9. [PMID: 26318175 DOI: 10.1007/s11262-015-1241-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/20/2015] [Indexed: 12/11/2022]
Abstract
Coxsackievirus B3 (CVB3) infection causes central nervous system diseases including aseptic meningitis and encephalitis. To understand the mechanism of this virus, a yeast two-hybrid system was used to screen cellular proteins from a human heart cDNA library. The results revealed that the human Pleckstrin Homology Domain Retinal protein (PHR1), a PH domain-containing protein with low expression in the heart and high expression in the brain, interacts with CVB3 VP1, a major structural protein of CVB3. Yeast mating assays and in vitro coimmunoprecipitation verified the interaction between CVB3 VP1 and PHR1. An α-galactosidase assay indicated that of α-galactosidase activity was higher in positive clones than in controls suggesting a strong interaction. Furthermore, assay of deletion mutants defined the minimal region of PHR1 required for its interaction with VP1 as amino acids 95-172 and two regions of VP1 required for its interaction with PHR1 as amino acids 729-767 and 811-859. The results revealed multiple binding sites between PHR1 and CVB3 VP1 and suggested that the strong interaction between these two proteins might play an important role in central nervous system disease in the human brain.
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Dörr A, Pierre S, Zhang DD, Henke M, Holland S, Scholich K. MYCBP2 Is a Guanosine Exchange Factor for Ran Protein and Determines Its Localization in Neurons of Dorsal Root Ganglia. J Biol Chem 2015; 290:25620-35. [PMID: 26304119 DOI: 10.1074/jbc.m115.646901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Indexed: 11/06/2022] Open
Abstract
The small GTPase Ran coordinates retrograde axonal transport in neurons, spindle assembly during mitosis, and the nucleo-cytoplasmic transport of mRNA. Its localization is tightly regulated by the GTPase-activating protein RanGAP1 and the nuclear guanosine exchange factor (GEF) RCC1. We show that loss of the neuronal E3 ubiquitin ligase MYCBP2 caused the up-regulation of Ran and RanGAP1 in dorsal root ganglia (DRG) under basal conditions and during inflammatory hyperalgesia. SUMOylated RanGAP1 physically interacted with MYCBP2 and inhibited its E3 ubiquitin ligase activity. Stimulation of neurons induced a RanGAP1-dependent translocation of MYCBP2 to the nucleus. In the nucleus of DRG neurons MYCBP2 co-localized with Ran and facilitated through its RCC1-like domain the GDP/GTP exchange of Ran. In accordance with the necessity of a GEF to promote GTP-binding and nuclear export of Ran, the nuclear localization of Ran was strongly increased in MYCBP2-deficient DRGs. The finding that other GEFs for Ran besides RCC1 exist gives new insights in the complexity of the regulation of the Ran signaling pathway.
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Affiliation(s)
- Angela Dörr
- From the Institut für Klinische Pharmakologie, Pharmazentrum Frankfurt, Klinikum der Goethe-Universität Frankfurt, Frankfurt 60590, Germany
| | - Sandra Pierre
- From the Institut für Klinische Pharmakologie, Pharmazentrum Frankfurt, Klinikum der Goethe-Universität Frankfurt, Frankfurt 60590, Germany
| | - Dong D Zhang
- From the Institut für Klinische Pharmakologie, Pharmazentrum Frankfurt, Klinikum der Goethe-Universität Frankfurt, Frankfurt 60590, Germany
| | - Marina Henke
- From the Institut für Klinische Pharmakologie, Pharmazentrum Frankfurt, Klinikum der Goethe-Universität Frankfurt, Frankfurt 60590, Germany
| | - Sabrina Holland
- From the Institut für Klinische Pharmakologie, Pharmazentrum Frankfurt, Klinikum der Goethe-Universität Frankfurt, Frankfurt 60590, Germany
| | - Klaus Scholich
- From the Institut für Klinische Pharmakologie, Pharmazentrum Frankfurt, Klinikum der Goethe-Universität Frankfurt, Frankfurt 60590, Germany
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Bredrup C, Johansson S, Bindoff LA, Sztromwasser P, Kråkenes J, Mellgren AE, Brurås KR, Lind O, Boman H, Knappskog PM, Rødahl E. High myopia-excavated optic disc anomaly associated with a frameshift mutation in the MYC-binding protein 2 gene (MYCBP2). Am J Ophthalmol 2015; 159:973-9.e2. [PMID: 25634536 DOI: 10.1016/j.ajo.2015.01.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 01/21/2015] [Accepted: 01/21/2015] [Indexed: 12/30/2022]
Abstract
PURPOSE To investigate the ocular and neurologic manifestations, and to identify the causative mutation in a family with an excavated optic disc anomaly, high myopia, enlarged axial lengths, and abnormal visual evoked response (VER). DESIGN Prospective observational case series with whole exome sequencing. METHODS Institutional study of 8 family members from 3 generations. Clinical examination included visual field examination, optical coherence tomography, axial length measurement, audiometry, visual evoked response (VER), orbital and cerebral magnetic resonance imaging (MRI), and renal ultrasound. DNA was analyzed by whole exome sequencing and Sanger sequencing. Main outcome measures were clinical and radiological findings, and DNA sequence data. RESULTS Three affected family members, a father and his 2 daughters, were examined. The parents and siblings of the father were healthy. Affected individuals presented with excavated optic discs, high myopia (-1.00 to -16.00 diopters), and increased axial lengths. Reduced visual acuity (0.05-0.8) and decreased sensitivity on visual field examination were observed. VER revealed prolonged latency times. Affected eyes appeared ovoid on MRI and the father had thin optic nerves. Exome sequencing revealed that the father was heterozygous for a de novo 5 bp deletion in MYCBP2, c.5906_5910del; p.Glu1969Valfs*26. The same mutation was found in his 2 affected daughters, but not in his parents or siblings, or in public databases. CONCLUSION We describe a distinct excavated optic disc anomaly associated with high myopia and increased axial length. The condition appears to follow an autosomal dominant pattern and segregate with a deletion in MYCBP2. We suggest naming this entity high myopia-excavated optic disc anomaly.
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Chai G, Goffinet AM, Tissir F. Celsr3 and Fzd3 in axon guidance. Int J Biochem Cell Biol 2015; 64:11-4. [PMID: 25813877 DOI: 10.1016/j.biocel.2015.03.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 03/10/2015] [Accepted: 03/16/2015] [Indexed: 12/21/2022]
Abstract
The assembly of functional neuronal circuits depends on the correct wiring of axons and dendrites. To reach their targets, axons are guided by a variety of extracellular guidance cues, including Netrins, Ephrins, Semaphorins and Slits. Corresponding receptors in the growth cone, the dynamic structure at the tip of the growing axon, sense and integrate these positional signals, and activate downstream effectors to regulate cytoskeletal organization. In addition to the four canonical families of axon guidance cues mentioned above, some proteins that regulate planar cell polarity were recently found to be critical for axon guidance. The seven-transmembrane domain receptors Celsr3 and Fzd3, in particular, control the development of most longitudinal tracts in the central nervous system, and axon navigation in the peripheral, sympathetic and enteric nervous systems. Despite their unequivocally important role, however, underlying molecular mechanisms remain elusive. We do not know which extracellular ligands they recognize, whether they have co-receptors in the growth cone, and what their downstream effectors are. Here, we review some recent advances and discuss future trends in this emerging field.
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Affiliation(s)
- Guoliang Chai
- Institute of Neuroscience, Université catholique de Louvain, 73 Avenue Mounier, B1.73.16, Brussels 1200, Belgium
| | - Andre M Goffinet
- Institute of Neuroscience, Université catholique de Louvain, 73 Avenue Mounier, B1.73.16, Brussels 1200, Belgium.
| | - Fadel Tissir
- Institute of Neuroscience, Université catholique de Louvain, 73 Avenue Mounier, B1.73.16, Brussels 1200, Belgium.
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Cherra SJ, Jin Y. Advances in synapse formation: forging connections in the worm. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2015; 4:85-97. [PMID: 25472860 PMCID: PMC4339659 DOI: 10.1002/wdev.165] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 10/09/2014] [Accepted: 10/24/2014] [Indexed: 12/27/2022]
Abstract
UNLABELLED Synapse formation is the quintessential process by which neurons form specific connections with their targets to enable the development of functional circuits. Over the past few decades, intense research efforts have identified thousands of proteins that localize to the pre- and postsynaptic compartments. Genetic dissection has provided important insights into the nexus of the molecular and cellular network, and has greatly advanced our knowledge about how synapses form and function physiologically. Moreover, recent studies have highlighted the complex regulation of synapse formation with the identification of novel mechanisms involving cell interactions from non-neuronal sources. In this review, we cover the conserved pathways required for synaptogenesis and place specific focus on new themes of synapse modulation arising from studies in Caenorhabditis elegans. For further resources related to this article, please visit the WIREs website. CONFLICT OF INTEREST The authors have declared no conflicts of interest for this article.
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Affiliation(s)
- Salvatore J. Cherra
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego
- Howard Hughes Medical Institute
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46
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Holland S, Scholich K. Regulation of neuronal functions by the E3-ubiquitinligase Protein Associated with MYC (MYCBP2). Commun Integr Biol 2014. [DOI: 10.4161/cib.15967] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Sharma J, Baker ST, Turgeon SM, Gurney AM, Opperman KJ, Grill B. Identification of a peptide inhibitor of the RPM-1 · FSN-1 ubiquitin ligase complex. J Biol Chem 2014; 289:34654-66. [PMID: 25326385 DOI: 10.1074/jbc.m114.614065] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The Pam/Highwire/RPM-1 (PHR) proteins include: Caenorhabditis elegans RPM-1 (Regulator of Presynaptic Morphology 1), Drosophila Highwire, and murine Phr1. These important regulators of neuronal development function in synapse formation, axon guidance, and axon termination. In mature neurons the PHR proteins also regulate axon degeneration and regeneration. PHR proteins function, in part, through an ubiquitin ligase complex that includes the F-box protein FSN-1 in C. elegans and Fbxo45 in mammals. At present, the structure-function relationships that govern formation of this complex are poorly understood. We cloned 9 individual domains that compose the entire RPM-1 protein sequence and found a single domain centrally located in RPM-1 that is sufficient for binding to FSN-1. Deletion analysis further refined FSN-1 binding to a conserved 97-amino acid region of RPM-1. Mutagenesis identified several conserved motifs and individual amino acids that mediate this interaction. Transgenic overexpression of this recombinant peptide, which we refer to as the RPM-1·FSN-1 complex inhibitory peptide (RIP), yields similar phenotypes and enhancer effects to loss of function in fsn-1. Defects caused by transgenic RIP were suppressed by loss of function in the dlk-1 MAP3K and were alleviated by point mutations that reduce binding to FSN-1. These findings suggest that RIP specifically inhibits the interaction between RPM-1 and FSN-1 in vivo, thereby blocking formation of a functional ubiquitin ligase complex. Our results are consistent with the FSN-1 binding domain of RPM-1 recruiting FSN-1 and a target protein, such as DLK-1, whereas the RING-H2 domain of RPM-1 ubiquitinates the target.
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Affiliation(s)
- Jaiprakash Sharma
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, 33458 and
| | - Scott T Baker
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, 33458 and Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455
| | - Shane M Turgeon
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, 33458 and
| | - Allison M Gurney
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455
| | - Karla J Opperman
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, 33458 and
| | - Brock Grill
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, 33458 and
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Abstract
Motoneuron death after transection of the axons (axotomy) in neonates is believed to share the same mechanistic bases as naturally occurring programmed cell death during development. The c-Jun N-terminal kinase pathway is activated in both forms of motoneuron death, but it remains unknown to what extent these two forms of motoneuron death depend on this pathway and which upstream kinases are involved. We found that numbers of facial motoneurons are doubled in neonatal mice deficient in either ZPK/DLK (zipper protein kinase, also known as dual leucine zipper kinase), a mitogen-activated protein kinase kinase kinase, or in MKK4/MAP2K4, a mitogen-activated protein kinase kinase directly downstream of ZPK/DLK, and that the facial motoneurons in those mutant mice are completely resistant to axotomy-induced death. Conditional deletion of MKK4/MAP2K4 in neurons further suggested that ZPK/DLK and MKK4/MAP2K4-dependent mechanisms underlying axotomy-induced death are motoneuron autonomous. Nevertheless, quantitative analysis of facial motoneurons during embryogenesis revealed that both ZPK/DLK and MKK4/MAP2K4-dependent and -independent mechanisms contribute to developmental elimination of excess motoneurons. In contrast to MKK4/MAP2K4, mice lacking MKK7/MAP2K7, another mitogen-activated protein kinase kinase directly downstream of ZPK/DLK, conditionally in neurons did not have excess facial motoneurons. However, some MKK7/MAP2K7-deficient facial motoneurons were resistant to axotomy-induced death, indicating a synergistic effect of MKK7/MAP2K7 on axotomy-induced death of these facial motoneurons. Together, our study provides compelling evidence for the pivotal roles of the ZPK/DLK and MKK4/MAP2K4-dependent mechanism in axotomy-induced motoneuron death in neonates and also demonstrates that axotomy-induced motoneuron death is not identical to developmental motoneuron death with respect to the involvement of ZPK/DLK, MKK4/MAP2K4 and MKK7/MAP2K7.
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Perlecan antagonizes collagen IV and ADAMTS9/GON-1 in restricting the growth of presynaptic boutons. J Neurosci 2014; 34:10311-24. [PMID: 25080592 DOI: 10.1523/jneurosci.5128-13.2014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the mature nervous system, a significant fraction of synapses are structurally stable over a long time scale. However, the mechanisms that restrict synaptic growth within a confined region are poorly understood. Here, we identified that in the C. elegans neuromuscular junction, collagens Type IV and XVIII, and the secreted metalloprotease ADAMTS/GON-1 are critical for growth restriction of presynaptic boutons. Without these components, ectopic boutons progressively invade into the nonsynaptic region. Perlecan/UNC-52 promotes the growth of ectopic boutons and functions antagonistically to collagen Type IV and GON-1 but not to collagen XVIII. The growth constraint of presynaptic boutons correlates with the integrity of the extracellular matrix basal lamina or basement membrane (BM), which surrounds chemical synapses. Fragmented BM appears in the region where ectopic boutons emerge. Further removal of UNC-52 improves the BM integrity and the tight association between BM and presynaptic boutons. Together, our results unravel the complex role of the BM in restricting the growth of presynaptic boutons and reveal the antagonistic function of perlecan on Type IV collagen and ADAMTS protein.
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50
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Chung FZ, Sahasrabuddhe AA, Ma K, Chen X, Basrur V, Lim MS, Elenitoba-Johnson KSJ. Fbxo45 inhibits calcium-sensitive proteolysis of N-cadherin and promotes neuronal differentiation. J Biol Chem 2014; 289:28448-59. [PMID: 25143387 DOI: 10.1074/jbc.m114.561241] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Fbxo45 is an atypical E3 ubiquitin ligase, which specifically targets proteins for ubiquitin-mediated degradation. Fbxo45 ablation results in defective neuronal differentiation and abnormal formation of neural connections; however, the mechanisms underlying these defects are poorly understood. Using an unbiased mass spectrometry-based proteomic screen, we show here that N-cadherin is a novel interactor of Fbxo45. N-cadherin specifically interacts with Fbxo45 through two consensus motifs overlapping the site of calcium-binding and dimerization of the cadherin molecule. N-cadherin interaction with Fbxo45 is significantly abrogated by calcium treatment. Surprisingly, Fbxo45 depletion by RNAi-mediated silencing results in enhanced proteolysis of N-cadherin. Conversely, ectopic expression of Fbxo45 results in decreased proteolysis of N-cadherin. Fbxo45 depletion results in dramatic reduction in N-cadherin expression, impaired neuronal differentiation, and diminished formation of neuronal processes. Our studies reveal an unanticipated role for an F-box protein that inhibits proteolysis in the regulation of a critical biological process.
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Affiliation(s)
| | | | - Kaiyu Ma
- From the Department of Pathology
| | | | | | - Megan S Lim
- From the Department of Pathology, the Center for Computational Medicine and Bioinformatics, and
| | - Kojo S J Elenitoba-Johnson
- From the Department of Pathology, the Center for Computational Medicine and Bioinformatics, and the Protein Folding Diseases Initiative, University of Michigan Medical School, Ann Arbor, Michigan 48109
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