1
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Foley K, Ward N, Hou H, Mayer A, McKee C, Xia H. Regulation of PP1 interaction with I-2, neurabin, and F-actin. Mol Cell Neurosci 2023; 124:103796. [PMID: 36442541 PMCID: PMC10038014 DOI: 10.1016/j.mcn.2022.103796] [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: 10/06/2022] [Revised: 11/16/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022] Open
Abstract
Reversible phosphorylation is a fundamental regulatory mechanism required for many biological processes and is coordinated by the opposing actions of protein kinases and phosphatases. Protein phosphatase 1 (PP1) is a major protein phosphatase that plays an important role in many fundamental physiological processes including synaptic transmission and memory formation. Here we investigate the regulation of PP1 by prominent signaling proteins and synaptic scaffolds including GSK3β, inhibitor-2 (I-2), neurabin (Nrb), and actin. While GSK3β is known to regulate PP1 via phosphorylation of the PP1-binding protein I-2, we found that GSK3β directly regulates PP1 via inhibitory phosphorylation in neurons. Additionally, using bioluminescence resonance energy transfer (BRET), we found that GSK3β alters PP1-I-2 interaction in living cells. The effect of GSK3β on PP1-I-2 interaction is independent of the PP1 C-terminal tail, contrary to predictions based on previous findings from purified proteins. I-2 has been shown to form a trimeric complex with PP1 and Nrb, a major synaptic scaffold for promoting PP1 localization to the actin cytoskeleton. Utilizing BRET, we found that Nrb promotes PP1-actin interaction, however no BRET was detected between I-2 and F-actin. Finally, we found that stabilizing F-actin promotes Nrb-PP1 binding and may also lead to conformational changes between Nrb-I-2 and Nrb-F-actin complexes. Overall, our findings elaborate the dynamic regulation of PP1 complexes by GSK3β, targeting proteins, and actin polymerization.
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Affiliation(s)
- Karl Foley
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY 14642, USA; Department of Neuroscience, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Nancy Ward
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Hailong Hou
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Abigail Mayer
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY 14642, USA; Department of Neuroscience, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Cody McKee
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY 14642, USA; Department of Neuroscience, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Houhui Xia
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY 14642, USA; Department of Neuroscience, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY 14642, USA.
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2
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Lanzafame M, Branca G, Landi C, Qiang M, Vaz B, Nardo T, Ferri D, Mura M, Iben S, Stefanini M, Peverali FA, Bini L, Orioli D. Cockayne syndrome group A and ferrochelatase finely tune ribosomal gene transcription and its response to UV irradiation. Nucleic Acids Res 2021; 49:10911-10930. [PMID: 34581821 PMCID: PMC8565352 DOI: 10.1093/nar/gkab819] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 08/10/2021] [Accepted: 09/12/2021] [Indexed: 11/14/2022] Open
Abstract
CSA and CSB proteins are key players in transcription-coupled nucleotide excision repair (TC-NER) pathway that removes UV-induced DNA lesions from the transcribed strands of expressed genes. Additionally, CS proteins play relevant but still elusive roles in other cellular pathways whose alteration may explain neurodegeneration and progeroid features in Cockayne syndrome (CS). Here we identify a CS-containing chromatin-associated protein complex that modulates rRNA transcription. Besides RNA polymerase I (RNAP1) and specific ribosomal proteins (RPs), the complex includes ferrochelatase (FECH), a well-known mitochondrial enzyme whose deficiency causes erythropoietic protoporphyria (EPP). Impairment of either CSA or FECH functionality leads to reduced RNAP1 occupancy on rDNA promoter that is associated to reduced 47S pre-rRNA transcription. In addition, reduced FECH expression leads to an abnormal accumulation of 18S rRNA that in primary dermal fibroblasts from CS and EPP patients results in opposed rRNA amounts. After cell irradiation with UV light, CSA triggers the dissociation of the CSA–FECH–CSB–RNAP1–RPs complex from the chromatin while it stabilizes its binding to FECH. Besides disclosing a function for FECH within nucleoli, this study sheds light on the still unknown mechanisms through which CSA modulates rRNA transcription.
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Affiliation(s)
- Manuela Lanzafame
- Institute of Molecular Genetics -L.L. Cavalli Sforza, CNR, 27100 Pavia, Italy
| | - Giulia Branca
- Institute of Molecular Genetics -L.L. Cavalli Sforza, CNR, 27100 Pavia, Italy
| | - Claudia Landi
- Department of Life Sciences, University of Siena, 53100 Siena, Italy
| | - Mingyue Qiang
- Department of Dermatology and Allergic Diseases, Ulm University, Albert-Einstein Allee 23, 89081 Ulm, Germany
| | - Bruno Vaz
- Institute of Molecular Genetics -L.L. Cavalli Sforza, CNR, 27100 Pavia, Italy
| | - Tiziana Nardo
- Institute of Molecular Genetics -L.L. Cavalli Sforza, CNR, 27100 Pavia, Italy
| | - Debora Ferri
- Institute of Molecular Genetics -L.L. Cavalli Sforza, CNR, 27100 Pavia, Italy
| | - Manuela Mura
- Institute of Molecular Genetics -L.L. Cavalli Sforza, CNR, 27100 Pavia, Italy
| | - Sebastian Iben
- Department of Dermatology and Allergic Diseases, Ulm University, Albert-Einstein Allee 23, 89081 Ulm, Germany
| | - Miria Stefanini
- Institute of Molecular Genetics -L.L. Cavalli Sforza, CNR, 27100 Pavia, Italy
| | - Fiorenzo A Peverali
- Institute of Molecular Genetics -L.L. Cavalli Sforza, CNR, 27100 Pavia, Italy
| | - Luca Bini
- Department of Life Sciences, University of Siena, 53100 Siena, Italy
| | - Donata Orioli
- Institute of Molecular Genetics -L.L. Cavalli Sforza, CNR, 27100 Pavia, Italy
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3
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Nørgaard S, Deng S, Cao W, Pocock R. Distinct CED-10/Rac1 domains confer context-specific functions in development. PLoS Genet 2018; 14:e1007670. [PMID: 30265669 PMCID: PMC6179291 DOI: 10.1371/journal.pgen.1007670] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 10/10/2018] [Accepted: 08/30/2018] [Indexed: 11/18/2022] Open
Abstract
Rac GTPases act as master switches to coordinate multiple interweaved signaling pathways. A major function for Rac GTPases is to control neurite development by influencing downstream effector molecules and pathways. In Caenorhabditis elegans, the Rac proteins CED-10, RAC-2 and MIG-2 act in parallel to control axon outgrowth and guidance. Here, we have identified a single glycine residue in the CED-10/Rac1 Switch 1 region that confers a non-redundant function in axon outgrowth but not guidance. Mutation of this glycine to glutamic acid (G30E) reduces GTP binding and inhibits axon outgrowth but does not affect other canonical CED-10 functions. This demonstrates previously unappreciated domain-specific functions within the CED-10 protein. Further, we reveal that when CED-10 function is diminished, the adaptor protein NAB-1 (Neurabin) and its interacting partner SYD-1 (Rho-GAP-like protein) can act as inhibitors of axon outgrowth. Together, we reveal that specific domains and residues within Rac GTPases can confer context-dependent functions during animal development. Brain development requires that neurite outgrowth and guidance are precisely regulated. Previous studies have shown that molecular switch proteins called Rac GTPases perform redundant functions in controlling neurite development. Using a pair of bilateral neurons in the nematode Caenorhabditis elegans to model neurite development, we found that a single amino acid in a conserved domain of the Rac GTPase CED-10 is crucial for controlling neurite outgrowth in a partially non-redundant manner. Further, we revealed that lesions in discrete domains in the CED-10 protein lead to distinct developmental defects. Therefore, our in vivo study proposes that regulation of distinct signalling pathways through Rac GTPase protein domains can drive different developmental outcomes.
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Affiliation(s)
- Steffen Nørgaard
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
- Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Shuer Deng
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Wei Cao
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Roger Pocock
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
- Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
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4
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Kuschal C, Botta E, Orioli D, Digiovanna JJ, Seneca S, Keymolen K, Tamura D, Heller E, Khan SG, Caligiuri G, Lanzafame M, Nardo T, Ricotti R, Peverali FA, Stephens R, Zhao Y, Lehmann AR, Baranello L, Levens D, Kraemer KH, Stefanini M. GTF2E2 Mutations Destabilize the General Transcription Factor Complex TFIIE in Individuals with DNA Repair-Proficient Trichothiodystrophy. Am J Hum Genet 2016; 98:627-42. [PMID: 26996949 DOI: 10.1016/j.ajhg.2016.02.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 02/10/2016] [Indexed: 12/24/2022] Open
Abstract
The general transcription factor IIE (TFIIE) is essential for transcription initiation by RNA polymerase II (RNA pol II) via direct interaction with the basal transcription/DNA repair factor IIH (TFIIH). TFIIH harbors mutations in two rare genetic disorders, the cancer-prone xeroderma pigmentosum (XP) and the cancer-free, multisystem developmental disorder trichothiodystrophy (TTD). The phenotypic complexity resulting from mutations affecting TFIIH has been attributed to the nucleotide excision repair (NER) defect as well as to impaired transcription. Here, we report two unrelated children showing clinical features typical of TTD who harbor different homozygous missense mutations in GTF2E2 (c.448G>C [p.Ala150Pro] and c.559G>T [p.Asp187Tyr]) encoding the beta subunit of transcription factor IIE (TFIIEβ). Repair of ultraviolet-induced DNA damage was normal in the GTF2E2 mutated cells, indicating that TFIIE was not involved in NER. We found decreased protein levels of the two TFIIE subunits (TFIIEα and TFIIEβ) as well as decreased phosphorylation of TFIIEα in cells from both children. Interestingly, decreased phosphorylation of TFIIEα was also seen in TTD cells with mutations in ERCC2, which encodes the XPD subunit of TFIIH, but not in XP cells with ERCC2 mutations. Our findings support the theory that TTD is caused by transcriptional impairments that are distinct from the NER disorder XP.
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Affiliation(s)
- Christiane Kuschal
- Dermatology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Elena Botta
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - Donata Orioli
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - John J Digiovanna
- Dermatology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Sara Seneca
- Center for Medical Genetics, Research Group Reproduction and Genetics, UZ Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium
| | - Kathelijn Keymolen
- Center for Medical Genetics, Research Group Reproduction and Genetics, UZ Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium
| | - Deborah Tamura
- Dermatology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Elizabeth Heller
- Dermatology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Sikandar G Khan
- Dermatology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Giuseppina Caligiuri
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - Manuela Lanzafame
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - Tiziana Nardo
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - Roberta Ricotti
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - Fiorenzo A Peverali
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy
| | - Robert Stephens
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702, USA; Advanced Biomedical Computing Center, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702, USA
| | - Yongmei Zhao
- Advanced Biomedical Computing Center, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702, USA
| | - Alan R Lehmann
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Laura Baranello
- Laboratory of Pathology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - David Levens
- Laboratory of Pathology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Kenneth H Kraemer
- Dermatology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
| | - Miria Stefanini
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy.
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5
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Revuelta M, Arteaga O, Alvarez A, Martinez-Ibargüen A, Hilario E. Characterization of Gene Expression in the Rat Brainstem After Neonatal Hypoxic–Ischemic Injury and Antioxidant Treatment. Mol Neurobiol 2016; 54:1129-1143. [DOI: 10.1007/s12035-016-9724-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 01/13/2016] [Indexed: 11/29/2022]
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6
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Orioli D, Compe E, Nardo T, Mura M, Giraudon C, Botta E, Arrigoni L, Peverali FA, Egly JM, Stefanini M. XPD mutations in trichothiodystrophy hamper collagen VI expression and reveal a role of TFIIH in transcription derepression. Hum Mol Genet 2012; 22:1061-73. [PMID: 23221806 DOI: 10.1093/hmg/dds508] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Mutations in the XPD subunit of the transcription/DNA repair factor (TFIIH) give rise to trichothiodystrophy (TTD), a rare hereditary multisystem disorder with skin abnormalities. Here, we show that TTD primary dermal fibroblasts contain low amounts of collagen type VI alpha1 subunit (COL6A1), a fundamental component of soft connective tissues. We demonstrate that COL6A1 expression is downregulated by the sterol regulatory element-binding protein-1 (SREBP-1) whose removal from the promoter is a key step in COL6A1 transcription upregulation in response to cell confluence. We provide evidence for TFIIH being involved in transcription derepression, thus highlighting a new function of TFIIH in gene expression regulation. The lack of COL6A1 upregulation in TTD is caused by the inability of the mutated TFIIH complexes to remove SREBP-1 from COL6A1 promoter and to sustain the subsequent high rate of COL6A1 transcription. This defect might account for the pathologic features that TTD shares with hereditary disorders because of mutations in COL6A genes.
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Affiliation(s)
- Donata Orioli
- Istituto di Genetica Molecolare CNR, Pavia 27100, Italy.
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7
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The ortholog conjecture is untestable by the current gene ontology but is supported by RNA sequencing data. PLoS Comput Biol 2012; 8:e1002784. [PMID: 23209392 PMCID: PMC3510086 DOI: 10.1371/journal.pcbi.1002784] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 10/02/2012] [Indexed: 11/19/2022] Open
Abstract
The ortholog conjecture posits that orthologous genes are functionally more similar than paralogous genes. This conjecture is a cornerstone of phylogenomics and is used daily by both computational and experimental biologists in predicting, interpreting, and understanding gene functions. A recent study, however, challenged the ortholog conjecture on the basis of experimentally derived Gene Ontology (GO) annotations and microarray gene expression data in human and mouse. It instead proposed that the functional similarity of homologous genes is primarily determined by the cellular context in which the genes act, explaining why a greater functional similarity of (within-species) paralogs than (between-species) orthologs was observed. Here we show that GO-based functional similarity between human and mouse orthologs, relative to that between paralogs, has been increasing in the last five years. Further, compared with paralogs, orthologs are less likely to be included in the same study, causing an underestimation in their functional similarity. A close examination of functional studies of homologs with identical protein sequences reveals experimental biases, annotation errors, and homology-based functional inferences that are labeled in GO as experimental. These problems and the temporary nature of the GO-based finding make the current GO inappropriate for testing the ortholog conjecture. RNA sequencing (RNA-Seq) is known to be superior to microarray for comparing the expressions of different genes or in different species. Our analysis of a large RNA-Seq dataset of multiple tissues from eight mammals and the chicken shows that the expression similarity between orthologs is significantly higher than that between within-species paralogs, supporting the ortholog conjecture and refuting the cellular context hypothesis for gene expression. We conclude that the ortholog conjecture remains largely valid to the extent that it has been tested, but further scrutiny using more and better functional data is needed.
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8
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Khan SH, Ahmad F, Ahmad N, Flynn DC, Kumar R. Protein-protein interactions: principles, techniques, and their potential role in new drug development. J Biomol Struct Dyn 2011; 28:929-38. [PMID: 21469753 DOI: 10.1080/07391102.2011.10508619] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
A vast network of genes is inter-linked through protein-protein interactions and is critical component of almost every biological process under physiological conditions. Any disruption of the biologically essential network leads to pathological conditions resulting into related diseases. Therefore, proper understanding of biological functions warrants a comprehensive knowledge of protein-protein interactions and the molecular mechanisms that govern such processes. The importance of protein-protein interaction process is highlighted by the fact that a number of powerful techniques/methods have been developed to understand how such interactions take place under various physiological and pathological conditions. Many of the key protein-protein interactions are known to participate in disease-associated signaling pathways, and represent novel targets for therapeutic intervention. Thus, controlling protein-protein interactions offers a rich dividend for the discovery of new drug targets. Availability of various tools to study and the knowledge of human genome have put us in a unique position to understand highly complex biological network, and the mechanisms involved therein. In this review article, we have summarized protein-protein interaction networks, techniques/methods of their binding/kinetic parameters, and the role of these interactions in the development of potential tools for drug designing.
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Affiliation(s)
- Shagufta H Khan
- Department of Basic Sciences, The Commonwealth Medical College, 501 Madison Avenue, Scranton, PA 18510, USA
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9
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Ruscher K, Shamloo M, Rickhag M, Ladunga I, Soriano L, Gisselsson L, Toresson H, Ruslim-Litrus L, Oksenberg D, Urfer R, Johansson BB, Nikolich K, Wieloch T. The sigma-1 receptor enhances brain plasticity and functional recovery after experimental stroke. Brain 2011; 134:732-46. [PMID: 21278085 DOI: 10.1093/brain/awq367] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Stroke leads to brain damage with subsequent slow and incomplete recovery of lost brain functions. Enriched housing of stroke-injured rats provides multi-modal sensorimotor stimulation, which improves recovery, although the specific mechanisms involved have not been identified. In rats housed in an enriched environment for two weeks after permanent middle cerebral artery occlusion, we found increased sigma-1 receptor expression in peri-infarct areas. Treatment of rats subjected to permanent or transient middle cerebral artery occlusion with 1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine dihydrochloride, an agonist of the sigma-1 receptor, starting two days after injury, enhanced the recovery of lost sensorimotor function without decreasing infarct size. The sigma-1 receptor was found in the galactocerebroside enriched membrane microdomains of reactive astrocytes and in neurons. Sigma-1 receptor activation increased the levels of the synaptic protein neurabin and neurexin in membrane rafts in the peri-infarct area, while sigma-1 receptor silencing prevented sigma-1 receptor-mediated neurite outgrowth in primary cortical neuronal cultures. In astrocytic cultures, oxygen and glucose deprivation induced sigma-1 receptor expression and actin dependent membrane raft formation, the latter blocked by sigma-1 receptor small interfering RNA silencing and pharmacological inhibition. We conclude that sigma-1 receptor activation stimulates recovery after stroke by enhancing cellular transport of biomolecules required for brain repair, thereby stimulating brain plasticity. Pharmacological targeting of the sigma-1 receptor provides new opportunities for stroke treatment beyond the therapeutic window of neuroprotection.
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MESH Headings
- Animals
- Astrocytes/drug effects
- Brain/drug effects
- Brain/metabolism
- Caveolin 1/genetics
- Caveolin 1/metabolism
- Cell Hypoxia/drug effects
- Cells, Cultured
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Environment
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/physiology
- Glucose/deficiency
- Infarction, Middle Cerebral Artery/drug therapy
- Infarction, Middle Cerebral Artery/metabolism
- Infarction, Middle Cerebral Artery/pathology
- Infarction, Middle Cerebral Artery/physiopathology
- Male
- Movement/drug effects
- Neurites/drug effects
- Neurites/physiology
- Neuronal Plasticity/drug effects
- Neuronal Plasticity/physiology
- Neurons/cytology
- Neurons/metabolism
- Nootropic Agents/pharmacology
- Nootropic Agents/therapeutic use
- Piperazines/pharmacology
- Piperazines/therapeutic use
- Protein Transport/drug effects
- Psychomotor Performance/drug effects
- RNA, Small Interfering/pharmacology
- Rats
- Rats, Inbred SHR
- Receptors, sigma/genetics
- Receptors, sigma/metabolism
- Recovery of Function/drug effects
- Recovery of Function/physiology
- Statistics, Nonparametric
- Transfection/methods
- Sigma-1 Receptor
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Affiliation(s)
- Karsten Ruscher
- Laboratory for Experimental Brain Research, Wallenberg Neuroscience Center, Lund University, BMCA13, 22184 Lund, Sweden
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10
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Nestor MW, Cai X, Stone MR, Bloch RJ, Thompson SM. The actin binding domain of βI-spectrin regulates the morphological and functional dynamics of dendritic spines. PLoS One 2011; 6:e16197. [PMID: 21297961 PMCID: PMC3031527 DOI: 10.1371/journal.pone.0016197] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 12/07/2010] [Indexed: 01/30/2023] Open
Abstract
Actin microfilaments regulate the size, shape and mobility of dendritic spines and are in turn regulated by actin binding proteins and small GTPases. The βI isoform of spectrin, a protein that links the actin cytoskeleton to membrane proteins, is present in spines. To understand its function, we expressed its actin-binding domain (ABD) in CA1 pyramidal neurons in hippocampal slice cultures. The ABD of βI-spectrin bundled actin in principal dendrites and was concentrated in dendritic spines, where it significantly increased the size of the spine head. These effects were not observed after expression of homologous ABDs of utrophin, dystrophin, and α-actinin. Treatment of slice cultures with latrunculin-B significantly decreased spine head size and decreased actin-GFP fluorescence in cells expressing the ABD of α-actinin, but not the ABD of βI-spectrin, suggesting that its presence inhibits actin depolymerization. We also observed an increase in the area of GFP-tagged PSD-95 in the spine head and an increase in the amplitude of mEPSCs at spines expressing the ABD of βI-spectrin. The effects of the βI-spectrin ABD on spine size and mEPSC amplitude were mimicked by expressing wild-type Rac3, a small GTPase that co-immunoprecipitates specifically with βI-spectrin in extracts of cultured cortical neurons. Spine size was normal in cells co-expressing a dominant negative Rac3 construct with the βI-spectrin ABD. We suggest that βI-spectrin is a synaptic protein that can modulate both the morphological and functional dynamics of dendritic spines, perhaps via interaction with actin and Rac3.
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Affiliation(s)
- Michael W. Nestor
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Training Program in Integrative Membrane Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Xiang Cai
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Michele R. Stone
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Robert J. Bloch
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Training Program in Integrative Membrane Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Scott M. Thompson
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Training Program in Integrative Membrane Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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11
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Kishi M. Axon or dendrite? cell biology and molecular pathways for neuronal cell asymmetry. J Neurosci Res 2008; 86:490-5. [PMID: 17680674 DOI: 10.1002/jnr.21457] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Young neurons polarize by specializing axons and dendrites from immature neurites. After synapse formations, they transmit electrical activity along the axon-dendrite axis, thereby working as functional units of the neural circuits. This axon-dendrite asymmetry is referred to as neuronal polarity. Although a great number of cell biological studies in vitro had been performed, little was known about the molecular events that establish the polarity. In the last several years, rapid advancement in molecular and genetic studies has unraveled the multiple signaling pathways. This paper summarizes current perspectives on the cell and molecular biological mechanisms of the neuronal polarization, to clarify future directions in this growing research field.
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Affiliation(s)
- Masashi Kishi
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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Vessey JP, Karra D. More than just synaptic building blocks: scaffolding proteins of the post-synaptic density regulate dendritic patterning. J Neurochem 2007; 102:324-32. [PMID: 17596209 DOI: 10.1111/j.1471-4159.2007.04662.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The dendritic arbor is responsible for receiving and consolidating neuronal input. Outgrowth and morphogenesis of the arbor are complex stages of development that are poorly understood. However, recent findings have identified synaptic scaffolding proteins as novel regulators of these important events. Scaffolding proteins are enriched in the post-synaptic density where they bind and bring into close proximity neurotransmitter receptors, signaling molecules, and regulators of the actin cytoskeleton. This property is important for dendritic spine morphogenesis and maintenance in the mature neuron. Scaffolding proteins are now being described as key regulators of neurite outgrowth, dendritic development, and pattern formation in immature neurons. These proteins, which include post-synaptic-95, Shank and Densin-180, as well as many of their interacting partners, appear to regulate both the microtubule and actin cytoskeleton to influence dendrite morphology. Through a large array of protein-protein interaction domains, scaffolding proteins are able to form large macromolecular complexes that include cytoskeletal motor proteins as well as microtubule and actin regulatory molecules. Together, the new findings form a persuasive argument that scaffolding proteins deliver critical regulatory elements to sites of dendritic outgrowth and branching to modulate the formation and maintenance of the dendritic arbor.
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Affiliation(s)
- John P Vessey
- Department of Neural Cell Biology, Center for Brain Research, Medical University of Vienna, Vienna, Austria.
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Causeret F, Jacobs T, Terao M, Heath O, Hoshino M, Nikolić M. Neurabin-I is phosphorylated by Cdk5: implications for neuronal morphogenesis and cortical migration. Mol Biol Cell 2007; 18:4327-42. [PMID: 17699587 PMCID: PMC2043560 DOI: 10.1091/mbc.e07-04-0372] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The correct morphology and migration of neurons, which is essential for the normal development of the nervous system, is enabled by the regulation of their cytoskeletal elements. We reveal that Neurabin-I, a neuronal-specific F-actin-binding protein, has an essential function in the developing forebrain. We show that gain and loss of Neurabin-I expression affect neuronal morphology, neurite outgrowth, and radial migration of differentiating cortical and hippocampal neurons, suggesting that tight regulation of Neurabin-I function is required for normal forebrain development. Importantly, loss of Neurabin-I prevents pyramidal neurons from migrating into the cerebral cortex, indicating its essential role during early stages of corticogenesis. We demonstrate that in neurons Rac1 activation is affected by the expression levels of Neurabin-I. Furthermore, the Cdk5 kinase, a key regulator of neuronal migration and morphology, directly phosphorylates Neurabin-I and controls its association with F-actin. Mutation of the Cdk5 phosphorylation site reduces the phenotypic consequences of Neurabin-I overexpression both in vitro and in vivo, suggesting that Neurabin-I function depends, at least in part, on its phosphorylation status. Together our findings provide new insight into the signaling pathways responsible for controlled changes of the F-actin cytoskeleton that are required for normal development of the forebrain.
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Affiliation(s)
- Frédéric Causeret
- *Department of Cellular and Molecular Neuroscience, Imperial College School of Medicine, Charing Cross Campus, London W6 8RP, United Kingdom; and
| | - Tom Jacobs
- *Department of Cellular and Molecular Neuroscience, Imperial College School of Medicine, Charing Cross Campus, London W6 8RP, United Kingdom; and
| | - Mami Terao
- Department of Pathology and Tumor Biology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Owen Heath
- *Department of Cellular and Molecular Neuroscience, Imperial College School of Medicine, Charing Cross Campus, London W6 8RP, United Kingdom; and
| | - Mikio Hoshino
- Department of Pathology and Tumor Biology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Margareta Nikolić
- *Department of Cellular and Molecular Neuroscience, Imperial College School of Medicine, Charing Cross Campus, London W6 8RP, United Kingdom; and
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Hung W, Hwang C, Po MD, Zhen M. Neuronal polarity is regulated by a direct interaction between a scaffolding protein, Neurabin, and a presynaptic SAD-1 kinase in Caenorhabditis elegans. Development 2006; 134:237-49. [PMID: 17151015 DOI: 10.1242/dev.02725] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The establishment of axon-dendrite identity in developing neurites is essential for the development of a functional nervous system. The SAD serine-threonine kinases have been implicated in regulating neuronal polarization and synapse formation. Here, we show that the C. elegans SAD-1 kinase regulates axonal identity and synapse formation through distinct mechanisms. We identified a scaffolding protein, Neurabin (NAB-1), as a physiological binding partner of SAD-1. Both sad-1 and nab-1 loss-of-function mutants display polarity defects in which synaptic vesicles accumulate in both axons and dendrites. We show that sad-1 and nab-1 function in the same genetic pathway to restrict axonal fate. Unlike sad-1, nab-1 mutants display normal morphology of vesicle clusters. Strikingly, although the physical interaction of NAB-1 with SAD-1 is necessary for polarity, it is dispensable for synapse morphology. We propose that Neurabin functions as a scaffold to facilitate SAD-1-mediated phosphorylation for substrates specific for restricting axonal fate during neuronal polarization.
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Affiliation(s)
- Wesley Hung
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital and Department of Microbiology and Medical Genetics, University of Toronto, Ontario, M5G 1X5, Canada
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