1
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Rong Y, Wang J, Hu T, Shi Z, Lang C, Liu W, Cai W, Sun Y, Zhang F, Zhang W. Ginsenoside Rg1 Regulates Immune Microenvironment and Neurological Recovery After Spinal Cord Injury Through MYCBP2 Delivery via Neuronal Cell-Derived Extracellular Vesicles. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2402114. [PMID: 38896802 DOI: 10.1002/advs.202402114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 05/31/2024] [Indexed: 06/21/2024]
Abstract
Spinal cord injury (SCI) is a severe neurological condition that frequently leads to significant sensory, motor, and autonomic dysfunction. This study sought to delineate the potential mechanistic underpinnings of extracellular vesicles (EVs) derived from ginsenoside Rg1-pretreated neuronal cells (Rg1-EVs) in ameliorating SCI. These results demonstrated that treatment with Rg1-EVs substantially improved motor function in spinal cord-injured mice. Rg1-EVs enhance microglial polarization toward the M2 phenotype and repressed oxidative stress, thereby altering immune responses and decreasing inflammatory cytokine secretion. Moreover, Rg1-EVs substantially diminish reactive oxygen species accumulation and enhanced neural tissue repair by regulating mitochondrial function. Proteomic profiling highlighted a significant enrichment of MYCBP2 in Rg1-EVs, and functional assays confirmed that MYCBP2 knockdown counteracted the beneficial effects of Rg1-EVs in vitro and in vivo. Mechanistically, MYCBP2 is implicated in the ubiquitination and degradation of S100A9, thereby promoting microglial M2-phenotype polarization and reducing oxidative stress. Overall, these findings substantiated the pivotal role of Rg1-EVs in neuronal protection and functional recovery following SCI through MYCBP2-mediated ubiquitination of S100A9. This research offers novel mechanistic insights into therapeutic strategies against SCI and supports the clinical potential of Rg1-EVs.
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Affiliation(s)
- Yuluo Rong
- Department of orthopaedics, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
- National Center for Translational Medicine (Shanghai) SHU Branch, Shanghai University, Shanghai, 200444, China
| | - Jiaxing Wang
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, China
| | - Tao Hu
- Department of orthopaedics, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Zhongming Shi
- Department of orthopaedics, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Chuandong Lang
- Department of orthopaedics, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Wei Liu
- Department of Orthopedics, Second Affiliated Hospital of Naval Medical University, Shanghai, 200003, China
| | - Weihua Cai
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, China
| | - Yongjin Sun
- Department of orthopaedics, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Feng Zhang
- Department of orthopaedics, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Wenzhi Zhang
- Department of orthopaedics, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
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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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3
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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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4
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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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5
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Drozd CJ, Quinn CC. UNC-116 and UNC-16 function with the NEKL-3 kinase to promote axon targeting. Development 2023; 150:dev201654. [PMID: 37756604 PMCID: PMC10561693 DOI: 10.1242/dev.201654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023]
Abstract
KIF5C is a kinesin-1 heavy chain that has been associated with neurodevelopmental disorders. Although the roles of kinesin-1 in axon transport are well known, little is known about how it regulates axon targeting. We report that UNC-116/KIF5C functions with the NEKL-3/NEK6/7 kinase to promote axon targeting in Caenorhabditis elegans. Loss of UNC-116 causes the axon to overshoot its target and UNC-116 gain-of-function causes premature axon termination. We find that loss of the UNC-16/JIP3 kinesin-1 cargo adaptor disrupts axon termination, but loss of kinesin-1 light chain function does not affect axon termination. Genetic analysis indicates that UNC-16 functions with the NEKL-3 kinase to promote axon termination. Consistent with this observation, imaging experiments indicate that loss of UNC-16 and UNC-116 disrupt localization of NEKL-3 in the axon. Moreover, genetic interactions suggest that NEKL-3 promotes axon termination by functioning with RPM-1, a ubiquitin ligase that regulates microtubule stability in the growth cone. These observations support a model where UNC-116 functions with UNC-16 to promote localization of NEKL-3 in the axon. NEKL-3, in turn, functions with the RPM-1 ubiquitin ligase to promote axon termination.
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Affiliation(s)
- Cody J. Drozd
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
| | - Christopher C. Quinn
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
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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: 7] [Impact Index Per Article: 7.0] [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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Saikia JM, Chavez-Martinez CL, Kim ND, Allibhoy S, Kim HJ, Simonyan L, Smadi S, Tsai KM, Romaus-Sanjurjo D, Jin Y, Zheng B. A Critical Role for DLK and LZK in Axonal Repair in the Mammalian Spinal Cord. J Neurosci 2022; 42:3716-3732. [PMID: 35361703 PMCID: PMC9087816 DOI: 10.1523/jneurosci.2495-21.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 02/23/2022] [Accepted: 03/24/2022] [Indexed: 11/21/2022] Open
Abstract
The limited ability for axonal repair after spinal cord injury underlies long-term functional impairment. Dual leucine-zipper kinase [DLK; MAP kinase kinase kinase 12; MAP3K12] is an evolutionarily conserved MAP3K implicated in neuronal injury signaling from Caenorhabditis elegans to mammals. However, whether DLK or its close homolog leucine zipper kinase (LZK; MAP3K13) regulates axonal repair in the mammalian spinal cord remains unknown. Here, we assess the role of endogenous DLK and LZK in the regeneration and compensatory sprouting of corticospinal tract (CST) axons in mice of both sexes with genetic analyses in a regeneration competent background provided by PTEN deletion. We found that inducible neuronal deletion of both DLK and LZK, but not either kinase alone, abolishes PTEN deletion-induced regeneration and sprouting of CST axons, and reduces naturally-occurring axon sprouting after injury. Thus, DLK/LZK-mediated injury signaling operates not only in injured neurons to regulate regeneration, but also unexpectedly in uninjured neurons to regulate sprouting. Deleting DLK and LZK does not interfere with PTEN/mTOR signaling, indicating that injury signaling and regenerative competence are independently controlled. Together with our previous study implicating LZK in astrocytic reactivity and scar formation, these data illustrate the multicellular function of this pair of MAP3Ks in both neurons and glia in the injury response of the mammalian spinal cord.SIGNIFICANCE STATEMENT Functional recovery after spinal cord injury is limited because of a lack of axonal repair in the mammalian CNS. Dual leucine-zipper kinase (DLK) and leucine zipper kinase (LZK) are two closely related protein kinases that have emerged as regulators of neuronal responses to injury. However, their role in axonal repair in the mammalian spinal cord has not been described. Here, we show that DLK and LZK together play critical roles in axonal repair in the mammalian spinal cord, validating them as potential targets to promote repair and recovery after spinal cord injury. In addition to regulating axonal regeneration from injured neurons, both kinases also regulate compensatory axonal growth from uninjured neurons, indicating a more pervasive role in CNS repair than originally anticipated.
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Affiliation(s)
- Junmi M Saikia
- Department of Neurosciences, School of Medicine
- Neurosciences Graduate Program
| | | | - Noah D Kim
- Department of Neurosciences, School of Medicine
| | | | - Hugo J Kim
- Department of Neurosciences, School of Medicine
| | | | | | | | | | - Yishi Jin
- Department of Neurosciences, School of Medicine
- Department of Neurobiology, School of Biological Sciences
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, California 92093
| | - Binhai Zheng
- Department of Neurosciences, School of Medicine
- VA San Diego Healthcare System Research Service, San Diego, California 92161
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8
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Desbois M, Opperman KJ, Amezquita J, Gaglio G, Crawley O, Grill B. Ubiquitin ligase activity inhibits Cdk5 to control axon termination. PLoS Genet 2022; 18:e1010152. [PMID: 35421092 PMCID: PMC9041834 DOI: 10.1371/journal.pgen.1010152] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 04/26/2022] [Accepted: 03/17/2022] [Indexed: 01/29/2023] Open
Abstract
The Cdk5 kinase plays prominent roles in nervous system development, plasticity, behavior and disease. It also has important, non-neuronal functions in cancer, the immune system and insulin secretion. At present, we do not fully understand negative regulatory mechanisms that restrict Cdk5. Here, we use Caenorhabditis elegans to show that CDK-5 is inhibited by the RPM-1/FSN-1 ubiquitin ligase complex. This atypical RING ubiquitin ligase is conserved from C. elegans through mammals. Our finding originated from unbiased, in vivo affinity purification proteomics, which identified CDK-5 as a putative RPM-1 substrate. CRISPR-based, native biochemistry showed that CDK-5 interacts with the RPM-1/FSN-1 ubiquitin ligase complex. A CRISPR engineered RPM-1 substrate ‘trap’ enriched CDK-5 binding, which was mediated by the FSN-1 substrate recognition module. To test the functional genetic relationship between the RPM-1/FSN-1 ubiquitin ligase complex and CDK-5, we evaluated axon termination in mechanosensory neurons and motor neurons. Our results indicate that RPM-1/FSN-1 ubiquitin ligase activity restricts CDK-5 to control axon termination. Collectively, these proteomic, biochemical and genetic results increase our understanding of mechanisms that restrain Cdk5 in the nervous system. Cdk5 is an atypical cyclin dependent kinase and an important player in nervous system development, plasticity, and disease. Decades of research has focused on understanding how Cdk5 is activated. In contrast, we know much less about the genetic and molecular mechanisms that restrict Cdk5 activity. Here, we examined how Cdk5 is inhibited in the nervous system using the model organism C. elegans. Our results indicate that the RPM-1/FSN-1 E3 ubiquitin ligase complex inhibits Cdk5 to control termination of axon growth. Our finding that ubiquitin ligase activity restricts Cdk5 in the nervous system in vivo now opens up the interesting possibility that ubiquitin ligase activity might regulate Cdk5 in other cellular contexts and disease settings.
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Affiliation(s)
- Muriel Desbois
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - Karla J. Opperman
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - Jonathan Amezquita
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington, United States of America
| | - Gabriel Gaglio
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Oliver Crawley
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Brock Grill
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington, United States of America
- Department of Pharmacology, University of Washington M1-A303/305 Behnke Conference Room, Arnold building, Seattle, Washington, United States of America
- * E-mail:
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9
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Lee HMT, Sayegh NY, Gayek AS, Jao SLJ, Chalfie M, Zheng C. Epistatic, synthetic, and balancing interactions among tubulin missense mutations affecting neurite growth in Caenorhabditis elegans. Mol Biol Cell 2020; 32:331-347. [PMID: 33378215 PMCID: PMC8098816 DOI: 10.1091/mbc.e20-07-0492] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mutations in tubulins affect microtubule (MT) dynamics and functions during neuronal differentiation and their genetic interaction provides insights into the regulation of MT functions. We previously used Caenorhabditis elegans touch receptor neurons to analyze the cellular impact of tubulin mutations and reported the phenotypes of 67 tubulin missense mutations, categorized into three classes: loss-of-function (lf), antimorphic (anti), and neomorphic (neo) alleles. In this study, we isolated 54 additional tubulin alleles through suppressor screens in sensitized backgrounds that caused excessive neurite growth. These alleles included 32 missense mutations not analyzed before, bringing the total number of mutations in our collection to 99. Phenotypic characterization of these newly isolated mutations identified three new types of alleles: partial lf and weak neo alleles of mec-7/β-tubulin that had subtle effects and strong anti alleles of mec-12/α-tubulin. We also discovered complex genetic interactions among the tubulin mutations, including the suppression of neo mutations by intragenic lf and anti alleles, additive and synthetic effects between mec-7 neo alleles, and unexpected epistasis, in which weaker neo alleles masked the effects of stronger neo alleles in inducing ectopic neurite growth. We also observed balancing between neo and anti alleles, whose respective MT-hyperstablizing and -destabilizing effects neutralized each other.
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Affiliation(s)
- Ho Ming Terence Lee
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
| | | | - A Sophia Gayek
- Department of Biological Sciences, Columbia University, New York, NY 10027
| | | | - Martin Chalfie
- Department of Biological Sciences, Columbia University, New York, NY 10027
| | - Chaogu Zheng
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
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10
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McCormick LE, Gupton SL. Mechanistic advances in axon pathfinding. Curr Opin Cell Biol 2020; 63:11-19. [PMID: 31927278 DOI: 10.1016/j.ceb.2019.12.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/02/2019] [Accepted: 12/02/2019] [Indexed: 02/08/2023]
Abstract
The development of a functional nervous system entails establishing connectivity between appropriate synaptic partners. During axonal pathfinding, the developing axon navigates through the extracellular environment, extending toward postsynaptic targets. In the early 1900s, Ramon y Cajal suggested that the growth cone, a specialized, dynamic, and cytoskeletal-rich structure at the tip of the extending axon, is guided by chemical cues in the extracellular environment. A century of work supports this hypothesis and introduced myriad guidance cues and receptors that promote a variety of growth cone behaviors including extension, pause, collapse, retraction, turning, and branching. Here, we highlight research from the last two years regarding pathways implicated in axon pathfinding.
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Affiliation(s)
- Laura E McCormick
- UNC Department of Cell Biology and Physiology, 111 Mason Farm Road, Chapel Hill, NC, 27599, USA
| | - Stephanie L Gupton
- UNC Department of Cell Biology and Physiology, 111 Mason Farm Road, Chapel Hill, NC, 27599, USA; UNC Neuroscience Center, 115 Mason Farm Road, Chapel Hill, NC, 27599, USA; UNC Lineberger Comprehensive Cancer Center, 101 Manning Dr, Chapel Hill, NC, 27514, USA.
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11
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Autophagy is inhibited by ubiquitin ligase activity in the nervous system. Nat Commun 2019; 10:5017. [PMID: 31676756 PMCID: PMC6825199 DOI: 10.1038/s41467-019-12804-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 10/01/2019] [Indexed: 12/17/2022] Open
Abstract
Autophagy is an intracellular catabolic process prominent in starvation, aging and disease. Neuronal autophagy is particularly important, as it affects the development and function of the nervous system, and is heavily implicated in neurodegenerative disease. Nonetheless, how autophagy is regulated in neurons remains poorly understood. Using an unbiased proteomics approach, we demonstrate that the primary initiator of autophagy, the UNC-51/ULK kinase, is negatively regulated by the ubiquitin ligase RPM-1. RPM-1 ubiquitin ligase activity restricts UNC-51 and autophagosome formation within specific axonal compartments, and exerts effects broadly across the nervous system. By restraining UNC-51 activity, RPM-1 inhibits autophagosome formation to affect axon termination, synapse maintenance and behavioral habituation. These results demonstrate how UNC-51 and autophagy are regulated subcellularly in axons, and unveils a mechanism for restricting initiation of autophagy across the nervous system. Our findings have important implications beyond nervous system development, given growing links between altered autophagy regulation and neurodegenerative diseases.
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12
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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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13
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Zhao G, Oztan A, Ye Y, Schwarz TL. Kinetochore Proteins Have a Post-Mitotic Function in Neurodevelopment. Dev Cell 2019; 48:873-882.e4. [PMID: 30827899 DOI: 10.1016/j.devcel.2019.02.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 11/14/2018] [Accepted: 01/31/2019] [Indexed: 01/04/2023]
Abstract
The kinetochore is a complex of proteins, broadly conserved from yeast to man, that resides at the centromere and is essential for chromosome segregation in dividing cells. There are no known functions of the core complex outside of the centromere. We now show that the proteins of the kinetochore have an essential post-mitotic function in neurodevelopment. At the embryonic neuromuscular junction of Drosophila melanogaster, mutation or knockdown of many kinetochore components cause neurites to overgrow and prevent formation of normal synaptic boutons. Kinetochore proteins were detected in synapses and axons in Drosophila. In post-mitotic cultured hippocampal neurons, knockdown of mis12 increased the filopodia-like protrusions in this region. We conclude that the proteins of the kinetochore are repurposed to sculpt developing synapses and dendrites and thereby contribute to the correct development of neuronal circuits in both invertebrates and mammals.
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Affiliation(s)
- Guoli Zhao
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Asli Oztan
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Yingzhi Ye
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Thomas L Schwarz
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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14
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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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15
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Park EC, Rongo C. RPM-1 and DLK-1 regulate pioneer axon outgrowth by controlling Wnt signaling. Development 2018; 145:dev.164897. [PMID: 30093552 DOI: 10.1242/dev.164897] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 07/27/2018] [Indexed: 11/20/2022]
Abstract
Axons must correctly reach their targets for proper nervous system function, although we do not fully understand the underlying mechanism, particularly for the first 'pioneer' axons. In C. elegans, AVG is the first neuron to extend an axon along the ventral midline, and this pioneer axon facilitates the proper extension and guidance of follower axons that comprise the ventral nerve cord. Here, we show that the ubiquitin ligase RPM-1 prevents the overgrowth of the AVG axon by repressing the activity of the DLK-1/p38 MAPK pathway. Unlike in damaged neurons, where this pathway activates CEBP-1, we find that RPM-1 and the DLK-1 pathway instead regulate the response to extracellular Wnt cues in developing AVG axons. The Wnt LIN-44 promotes the posterior growth of the AVG axon. In the absence of RPM-1 activity, AVG becomes responsive to a different Wnt, EGL-20, through a mechanism that appears to be independent of canonical Fz-type receptors. Our results suggest that RPM-1 and the DLK-1 pathway regulate axon guidance and growth by preventing Wnt signaling crosstalk.
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Affiliation(s)
- Eun Chan Park
- The Waksman Institute, Department of Genetics, Rutgers The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Christopher Rongo
- The Waksman Institute, Department of Genetics, Rutgers The State University of New Jersey, Piscataway, NJ 08854, USA
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16
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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: 44] [Impact Index Per Article: 7.3] [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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17
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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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