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1.
J Cell Sci ; 137(9)2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38587100

RESUMO

During development, neurons achieve a stereotyped neuron type-specific morphology, which relies on dynamic support by microtubules (MTs). An important player is the augmin complex (hereafter augmin), which binds to existing MT filaments and recruits the γ-tubulin ring complex (γ-TuRC), to form branched MTs. In cultured neurons, augmin is important for neurite formation. However, little is known about the role of augmin during neurite formation in vivo. Here, we have revisited the role of mammalian augmin in culture and then turned towards the class four Drosophila dendritic arborization (c4da) neurons. We show that MT density is maintained through augmin in cooperation with the γ-TuRC in vivo. Mutant c4da neurons show a reduction of newly emerging higher-order dendritic branches and in turn also a reduced number of their characteristic space-filling higher-order branchlets. Taken together, our data reveal a cooperative function for augmin with the γ-TuRC in forming enough MTs needed for the appropriate differentiation of morphologically complex dendrites in vivo.


Assuntos
Dendritos , Proteínas de Drosophila , Proteínas Associadas aos Microtúbulos , Microtúbulos , Animais , Microtúbulos/metabolismo , Dendritos/metabolismo , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Associadas aos Microtúbulos/genética , Drosophila melanogaster/metabolismo , Tubulina (Proteína)/metabolismo , Drosophila/metabolismo , Humanos , Neurônios/metabolismo , Neurônios/citologia
2.
Cell Death Dis ; 14(8): 540, 2023 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-37607937

RESUMO

Accumulating evidence has shown that the quality of proteins must be tightly monitored and controlled to maintain cellular proteostasis. Misfolded proteins and protein aggregates are targeted for degradation through the ubiquitin proteasome (UPS) and autophagy-lysosome systems. The ubiquitination and deubiquitinating enzymes (DUBs) have been reported to play pivotal roles in the regulation of the UPS system. However, the function of DUBs in the regulation of autophagy remain to be elucidated. In this study, we found that knockdown of Leon/USP5 caused a marked increase in the formation of autophagosomes and autophagic flux under well-fed conditions. Genetic analysis revealed that overexpression of Leon suppressed Atg1-induced cell death in Drosophila. Immunoblotting assays further showed a strong interaction between Leon/USP5 and the autophagy initiating kinase Atg1/ULK1. Depletion of Leon/USP5 led to increased levels of Atg1/ULK1. Our findings indicate that Leon/USP5 is an autophagic DUB that interacts with Atg1/ULK1, negatively regulating the autophagic process.


Assuntos
Autofagia , Proteínas de Drosophila , Animais , Autofagia/genética , Autofagossomos , Morte Celular , Drosophila , Lisossomos , Complexo de Endopeptidases do Proteassoma , Ubiquitina , Enzimas Desubiquitinantes , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/genética , Proteínas de Drosophila/genética , Proteases Específicas de Ubiquitina/genética
3.
Int J Mol Sci ; 23(19)2022 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-36233046

RESUMO

Parkinson's disease is one of the most common neurodegenerative diseases affecting the ageing population, with a prevalence that has doubled over the last 30 years. As the mechanism of the disease is not fully elucidated, the current treatments are unable to effectively prevent neurodegeneration. Studies have found that mutations in Leucine-rich-repeat-kinase 2 (LRRK2) are the most common cause of familial Parkinson's disease (PD). Moreover, aberrant (higher) LRRK2 kinase activity has an influence in idiopathic PD as well. Hence, the aim of this review is to categorize and synthesize current information related to LRRK2-linked PD and present the factors associated with LRRK2 that can be targeted therapeutically. A systematic review was conducted using the databases PubMed, Medline, SCOPUS, SAGE, and Cochrane (January 2016 to July 2021). Search terms included "Parkinson's disease", "mechanism", "LRRK2", and synonyms in various combinations. The search yielded a total of 988 abstracts for initial review, 80 of which met the inclusion criteria. Here, we emphasize molecular mechanisms revealed in recent in vivo and in vitro studies. By consolidating the recent updates in the field of LRRK2-linked PD, researchers can further evaluate targets for therapeutic application.


Assuntos
Doenças Neurodegenerativas , Doença de Parkinson , Humanos , Leucina/uso terapêutico , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/genética , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/metabolismo , Mutação , Doenças Neurodegenerativas/metabolismo , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/genética
4.
Cell Rep ; 40(12): 111372, 2022 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-36130510

RESUMO

Golgi outposts (GOPs) in dendrites are known for their role in promoting branch extension, but whether GOPs have other functions is unclear. We found that terminal branches of Drosophila class IV dendritic arborization (C4da) neurons actively grow during the early third-instar (E3) larval stage but retract in the late third (L3) stage. Interestingly, the Fringe (Fng) glycosyltransferase localizes increasingly at GOPs in distal dendritic regions through the E3 to the L3 stage. Expression of the endopeptidase Furin 2 (Fur2), which proteolyzes and inactivates Fng, decreases from E3 to L3 in C4da neurons, thereby increasing Fng-positive GOPs in dendrites. The epidermal Delta ligand and neuronal Notch receptor, the substrate for Fng-mediated O-glycosylation, also negatively regulate dendrite growth. Fng inhibits actin dynamics in dendrites, linking dendritic branch retraction to suppression of the C4da-mediated thermal nociception response in late larval stages. Thus, Fng-positive GOPs function in dendrite retraction, which would add another function to the repertoire of GOPs in dendrite arborization.


Assuntos
Dendritos , Proteínas de Drosophila , Actinas/metabolismo , Animais , Dendritos/metabolismo , Drosophila/metabolismo , Proteínas de Drosophila/metabolismo , Furina/metabolismo , Glicosiltransferases/metabolismo , Larva/metabolismo , Ligantes , Receptores Notch/metabolismo , Células Receptoras Sensoriais/metabolismo
5.
Elife ; 102021 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-34779396

RESUMO

The most frequent missense mutations in familial Parkinson's disease (PD) occur in the highly conserved LRRK2/PARK8 gene with G2019S mutation. We previously established a fly model of PD carrying the LRRK2-G2019S mutation that exhibited the parkinsonism-like phenotypes. An herbal medicine, Gastrodia elata Blume (GE), has been reported to have neuroprotective effects in toxin-induced PD models. However, the underpinning molecular mechanisms of GE beneficiary to G2019S-induced PD remain unclear. Here, we show that these G2019S flies treated with water extracts of GE (WGE) and its bioactive compounds, gastrodin and 4-HBA, displayed locomotion improvement and dopaminergic neuron protection. WGE suppressed the accumulation and hyperactivation of G2019S proteins in dopaminergic neurons and activated the antioxidation and detoxification factor Nrf2 mostly in the astrocyte-like and ensheathing glia. Glial activation of Nrf2 antagonizes G2019S-induced Mad/Smad signaling. Moreover, we treated LRRK2-G2019S transgenic mice with WGE and found that the locomotion declines, the loss of dopaminergic neurons, and the number of hyperactive microglia were restored. WGE also suppressed the hyperactivation of G2019S proteins and regulated the Smad2/3 pathways in the mice brains. We conclude that WGE prevents locomotion defects and the neuronal loss induced by G2019S mutation via glial Nrf2/Mad signaling, unveiling a potential therapeutic avenue for PD.


Parkinson's disease is a brain disorder that leads to tremors and difficulties with balance and coordination. These symptoms are caused by the loss of neurons which release a chemical messenger that is needed to regulate movement called dopamine. Most treatments for this disease work by boosting levels of dopamine in the brain, but this can lead to severe side effects and these drugs often become less effective over time. A traditional Chinese medicine called Gastrodia elata Blume (or GE for short) has previously been reported to relieve symptoms of Parkinson's disease in both human and animal studies when administered as a decoction or formula. However, it is unclear how GE protects dopamine-producing neurons and if this mechanism involves another type of brain cell known as glia that has also been linked to Parkinson's disease. To investigate, Lin et al. studied fruit flies and mice that carry a genetic mutation that produces the symptoms and molecular characteristics of Parkinson's disease. The experiments showed that when the flies and mice were fed food containing water extracts of GE, they experienced less difficulties moving and had a higher number of intact dopamine-producing neurons. Lin et al. found that GE switched on a protein in glial cells located near dopamine-producing neurons. Activation of this protein, called Nrf2, inhibited a signaling pathway in degenerating neurons that leads to the disease state. As a result, less dopamine-producing neurons were damaged and the animals' coordination and balance were maintained. These findings suggest that GE could potentially provide an alternative or complementary therapy for Parkinson's disease, although it still needs to be studied further in humans. If the same effect is observed, the specific compounds in GE that have this protective effect could be isolated and analyzed to see if they could be used for treatment.


Assuntos
Gastrodia/química , Fator 2 Relacionado a NF-E2/metabolismo , Fármacos Neuroprotetores/farmacologia , Doença de Parkinson/tratamento farmacológico , Extratos Vegetais/farmacologia , Transdução de Sinais , Animais , Álcoois Benzílicos/farmacologia , Butiratos/farmacologia , Modelos Animais de Doenças , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Drosophila melanogaster , Glucosídeos/farmacologia , Locomoção/efeitos dos fármacos , Camundongos , Neuroglia/fisiologia , Neuroproteção
6.
Front Cell Neurosci ; 14: 577315, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33100975

RESUMO

Dendritic morphology is inextricably linked to neuronal function. Systematic large-scale screens combined with genetic mapping have uncovered several mechanisms underlying dendrite morphogenesis. However, a comprehensive overview of participating molecular mechanisms is still lacking. Here, we conducted an efficient clonal screen using a collection of mapped P-element insertions that were previously shown to cause lethality and eye defects in Drosophila melanogaster. Of 280 mutants, 52 exhibited dendritic defects. Further database analyses, complementation tests, and RNA interference validations verified 40 P-element insertion genes as being responsible for the dendritic defects. Twenty-eight mutants presented severe arbor reduction, and the remainder displayed other abnormalities. The intrinsic regulators encoded by the identified genes participate in multiple conserved mechanisms and pathways, including the protein folding machinery and the chaperonin-containing TCP-1 (CCT) complex that facilitates tubulin folding. Mutant neurons in which expression of CCT4 or CCT5 was depleted exhibited severely retarded dendrite growth. We show that CCT localizes in dendrites and is required for dendritic microtubule organization and tubulin stability, suggesting that CCT-mediated tubulin folding occurs locally within dendrites. Our study also reveals novel mechanisms underlying dendrite morphogenesis. For example, we show that Drosophila Nogo signaling is required for dendrite development and that Mummy and Wech also regulate dendrite morphogenesis, potentially via Dpp- and integrin-independent pathways. Our methodology represents an efficient strategy for identifying intrinsic dendrite regulators, and provides insights into the plethora of molecular mechanisms underlying dendrite morphogenesis.

7.
Proc Natl Acad Sci U S A ; 116(49): 24651-24661, 2019 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-31666321

RESUMO

Secreted exosomal microRNAs (miRNAs) mediate interorgan/tissue communications by modulating target gene expression, thereby regulating developmental and physiological functions. However, the source, route, and function in target cells have not been formally established for specific miRNAs. Here, we show that glial miR-274 non-cell-autonomously modulates the growth of synaptic boutons and tracheal branches. Whereas the precursor form of miR-274 is expressed in glia, the mature form of miR-274 distributes broadly, including in synaptic boutons, muscle cells, and tracheal cells. Mature miR-274 is secreted from glia to the circulating hemolymph as an exosomal cargo, a process requiring ESCRT components in exosome biogenesis and Rab11 and Syx1A in exosome release. We further show that miR-274 can function in the neurons or tracheal cells to modulate the growth of synaptic boutons and tracheal branches, respectively. Also, miR-274 uptake into the target cells by AP-2-dependent mechanisms modulates target cell growth. In the target cells, miR-274 down-regulates Sprouty (Sty) through a targeting sequence at the sty 3' untranslated region, thereby enhancing MAPK signaling and promoting cell growth. miR-274 expressed in glia of an mir-274 null mutant is released as an exosomal cargo in the circulating hemolymph, and such glial-specific expression resets normal levels of Sty and MAPK signaling and modulates target cell growth. mir-274 mutant larvae are hypersensitive to hypoxia, which is suppressed by miR-274 expression in glia or by increasing tracheal branches. Thus, glia-derived miR-274 coordinates growth of synaptic boutons and tracheal branches to modulate larval hypoxia responses.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Proteínas de Membrana/genética , MicroRNAs/metabolismo , Neuroglia/metabolismo , Regiões 3' não Traduzidas/genética , Animais , Animais Geneticamente Modificados , Hipóxia Celular/genética , Regulação para Baixo , Exossomos/metabolismo , Feminino , Hemolinfa/metabolismo , Larva/crescimento & desenvolvimento , Larva/metabolismo , Sistema de Sinalização das MAP Quinases/genética , MicroRNAs/genética , Mutação , Terminações Pré-Sinápticas/metabolismo , Precursores de RNA/genética , Precursores de RNA/metabolismo , Traqueia/crescimento & desenvolvimento , Traqueia/metabolismo , Regulação para Cima
8.
PLoS Genet ; 15(8): e1007980, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31381576

RESUMO

Synaptic structure and activity are sensitive to environmental alterations. Modulation of synaptic morphology and function is often induced by signals from glia. However, the process by which glia mediate synaptic responses to environmental perturbations such as hypoxia remains unknown. Here, we report that, in the mutant for Trachealess (Trh), the Drosophila homolog for NPAS1 and NPAS3, smaller synaptic boutons form clusters named satellite boutons appear at larval neuromuscular junctions (NMJs), which is induced by the reduction of internal oxygen levels due to defective tracheal branches. Thus, the satellite bouton phenotype in the trh mutant is suppressed by hyperoxia, and recapitulated in wild-type larvae raised under hypoxia. We further show that hypoxia-inducible factor (HIF)-1α/Similar (Sima) is critical in mediating hypoxia-induced satellite bouton formation. Sima upregulates the level of the Wnt/Wingless (Wg) signal in glia, leading to reorganized microtubule structures within presynaptic sites. Finally, hypoxia-induced satellite boutons maintain normal synaptic transmission at the NMJs, which is crucial for coordinated larval locomotion.


Assuntos
Hipóxia Celular/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Junção Neuromuscular/crescimento & desenvolvimento , Transmissão Sináptica/fisiologia , Fatores de Transcrição/metabolismo , Animais , Animais Geneticamente Modificados , Proteínas de Drosophila/genética , Drosophila melanogaster/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Silenciamento de Genes , Microscopia Intravital , Larva/fisiologia , Locomoção/genética , Microscopia Confocal , Microtúbulos/metabolismo , Modelos Animais , Neuroglia/citologia , Neuroglia/metabolismo , Junção Neuromuscular/metabolismo , Terminações Pré-Sinápticas/metabolismo , Transdução de Sinais/genética , Fatores de Transcrição/genética , Regulação para Cima , Proteína Wnt1/metabolismo
9.
Curr Biol ; 29(9): 1445-1459.e3, 2019 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-31006568

RESUMO

Building sensory dendritic arbors requires branching, growth, spacing, and substrate support. The conserved L1CAM family of cell-adhesion molecules generates neuronal isoforms to regulate neurite development in various aspects. However, whether non-neuronal isoforms participate in any of these aspects is unclear. In Drosophila, the L1CAM homolog Neuroglian (Nrg) is expressed as two isoforms: the neuronal isoform Nrg180 on dendritic surfaces of dendritic arborization (da) neurons and the non-neuronal isoform Nrg167 in epidermis innervated by dendrites. We found that epidermal Nrg167 encircles dendrites by interactions with dendritic Nrg180 to support dendrite growth, stabilization, and enclosure inside epidermis. Interestingly, whereas Nrg180 forms homophilic interactions to facilitate axonal bundling, heteroneuronal dendrites in the same innervating field avoid bundling through unknown mechanisms to maintain individual dendritic patterns. Here, we show that both epidermal Nrg167 depletion and neuronal Nrg180 overexpression can cause dendrite bundling, with genetic analyses suggesting that Nrg167-Nrg180 interactions antagonize Nrg180-Nrg180 homophilic interaction to prevent dendrite bundling. Furthermore, internalization of Nrg180 also participates in resolving dendrite bundling, as overexpression of endocytosis-defective Nrg180 and compromising endocytosis in neurons both exacerbated dendrite-bundling defects. Together, our study highlights the functional significance of substrate-derived Nrg167 in conferring dendrite stability, positioning, and avoidance.


Assuntos
Moléculas de Adesão Celular Neuronais/genética , Dendritos/fisiologia , Proteínas de Drosophila/genética , Drosophila melanogaster/fisiologia , Animais , Moléculas de Adesão Celular Neuronais/metabolismo , Linhagem Celular , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Isoformas de Proteínas/metabolismo
10.
Open Biol ; 9(3): 180257, 2019 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-30914004

RESUMO

Sensing environmental cues requires well-built neuronal circuits linked to the body surface. Sensory neurons generate dendrites to innervate surface epithelium, thereby making it the largest sensory organ in the body. Previous studies have illustrated that neuronal type, physiological function and branching patterns are determined by intrinsic factors. Perhaps for effective sensation or protection, sensory dendrites bind to or are surrounded by the substrate epidermis. Recent studies have shed light on the mechanisms by which dendrites interact with their substrates. These interactions suggest that substrates can regulate dendrite guidance, arborization and degeneration. In this review, we focus on recent studies of Drosophila and Caenorhabditis elegans that demonstrate how epidermal cells can regulate dendrites in several aspects.


Assuntos
Dendritos/metabolismo , Células Epidérmicas/metabolismo , Epiderme/metabolismo , Células Receptoras Sensoriais/metabolismo , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Drosophila/genética , Drosophila/metabolismo , Epiderme/inervação , Larva/genética , Larva/metabolismo , Microscopia Confocal , Imagem com Lapso de Tempo/métodos
11.
J Cell Biol ; 217(10): 3731-3746, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30042190

RESUMO

The actin cytoskeleton provides structural stability and adaptability to the cell. Neuronal dendrites frequently undergo morphological changes by emanating, elongating, and withdrawing branches. However, the knowledge about actin dynamics in dendrites during these processes is limited. By performing in vivo imaging of F-actin markers, we found that F-actin was highly dynamic and heterogeneously distributed in dendritic shafts with enrichment at terminal dendrites. A dynamic F-actin population that we named actin blobs propagated bidirectionally at an average velocity of 1 µm/min. Interestingly, these actin blobs stalled at sites where new dendrites would branch out in minutes. Overstabilization of F-actin by the G15S mutant abolished actin blobs and dendrite branching. We identified the F-actin-severing protein Tsr/cofilin as a regulator of dynamic actin blobs and branching activity. Hence, actin blob localization at future branching sites represents a dendrite-branching mechanism to account for highly diversified dendritic morphology.


Assuntos
Actinas/metabolismo , Dendritos/metabolismo , Proteínas de Drosophila/metabolismo , Actinas/genética , Substituição de Aminoácidos , Animais , Dendritos/genética , Proteínas de Drosophila/genética , Drosophila melanogaster , Mutação de Sentido Incorreto
12.
Neuron ; 98(2): 320-334.e6, 2018 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-29673481

RESUMO

Self-avoidance allows sister dendrites from the same neuron to form non-redundant coverage of the sensory territory and is important for neural circuitry functions. Here, we report an unexpected, cell-autonomous role of the Wnt-secretory factor MIG-14/Wntless in mediating dendrite self-avoidance in the C. elegans multidendritic PVD neurons. Similar findings in Drosophila suggest that this novel function of Wntless is conserved. The mig-14 mutant shows defects in dendrite self-avoidance, and ectopic MIG-14 expression triggers dendrite repulsion. Functions of dendrite self-avoidance and Wnt secretion could be mapped to distinct MIG-14 domains, indicating that these two functions of MIG-14 are genetically separable, consistent with lack of self-avoidance defects in the Wnt mutants. We further demonstrate that MIG-14 engages Wiskott-Aldrich syndrome protein (WASP)-dependent actin assembly to regulate dendrite self-avoidance. Our work expands the repertoire of self-avoidance molecules and uncovers a previously unknown, Wnt-independent function of MIG-14/Wntless.


Assuntos
Proteínas de Caenorhabditis elegans/biossíntese , Proteínas de Transporte/biossíntese , Comunicação Celular/fisiologia , Dendritos/fisiologia , Proteínas de Drosophila/biossíntese , Peptídeos e Proteínas de Sinalização Intracelular/biossíntese , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/análise , Proteínas de Transporte/análise , Dendritos/química , Proteínas de Drosophila/análise , Drosophila melanogaster , Células HeLa , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/análise , Masculino , Transporte Proteico/fisiologia , Via de Sinalização Wnt/fisiologia
13.
Elife ; 62017 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-28489002

RESUMO

Synapse formation and growth are tightly controlled processes. How synaptic growth is terminated after reaching proper size remains unclear. Here, we show that Leon, the Drosophila USP5 deubiquitinase, controls postsynaptic growth. In leon mutants, postsynaptic specializations of neuromuscular junctions are dramatically expanded, including the subsynaptic reticulum, the postsynaptic density, and the glutamate receptor cluster. Expansion of these postsynaptic features is caused by a disruption of ubiquitin homeostasis with accumulation of free ubiquitin chains and ubiquitinated substrates in the leon mutant. Accumulation of Ubiquilin (Ubqn), the ubiquitin receptor whose human homolog ubiquilin 2 is associated with familial amyotrophic lateral sclerosis, also contributes to defects in postsynaptic growth and ubiquitin homeostasis. Importantly, accumulations of postsynaptic proteins cause different aspects of postsynaptic overgrowth in leon mutants. Thus, the deubiquitinase Leon maintains ubiquitin homeostasis and proper Ubqn levels, preventing postsynaptic proteins from accumulation to confine postsynaptic growth.


Assuntos
Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas de Drosophila/metabolismo , Densidade Pós-Sináptica/metabolismo , Receptores de Glutamato/metabolismo , Proteases Específicas de Ubiquitina/metabolismo , Ubiquitina/metabolismo , Animais , Drosophila , Homeostase
14.
Sci Rep ; 7: 39856, 2017 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-28051179

RESUMO

Differentiated neurons and glia are acquired from immature precursors via transcriptional controls exerted by factors such as proteins in the family of Glial Cells Missing (Gcm). Mammalian Gcm proteins mediate neural stem cell induction, placenta and parathyroid development, whereas Drosophila Gcm proteins act as a key switch to determine neuronal and glial cell fates and regulate hemocyte development. The present study reports a hypoparathyroidism-associated mutation R59L that alters Drosophila Gcm (Gcm) protein stability, rendering it unstable, and hyperubiquitinated via the ubiquitin-proteasome system (UPS). GcmR59L interacts with the Slimb-based SCF complex and Protein Kinase C (PKC), which possibly plays a role in its phosphorylation, hence altering ubiquitination. Additionally, R59L causes reduced Gcm protein levels in a manner independent of the PEST domain signaling protein turnover. GcmR59L proteins bind DNA, functionally activate transcription, and induce glial cells, yet at a less efficient level. Finally, overexpression of either wild-type human Gcmb (hGcmb) or hGcmb carrying the conserved hypoparathyroidism mutation only slightly affects gliogenesis, indicating differential regulatory mechanisms in human and flies. Taken together, these findings demonstrate the significance of this disease-associated mutation in controlling Gcm protein stability via UPS, hence advance our understanding on how glial formation is regulated.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Hipoparatireoidismo/patologia , Neuroglia/metabolismo , Fatores de Transcrição/metabolismo , Animais , DNA/metabolismo , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Proteínas de Drosophila/antagonistas & inibidores , Proteínas de Drosophila/química , Proteínas de Drosophila/genética , Humanos , Hipoparatireoidismo/metabolismo , Leupeptinas/farmacologia , Neuroglia/citologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Fosforilação/efeitos dos fármacos , Polimorfismo de Nucleotídeo Único , Complexo de Endopeptidases do Proteassoma/metabolismo , Ligação Proteica , Proteína Quinase C/metabolismo , Estabilidade Proteica , Fatores de Transcrição/química , Fatores de Transcrição/genética , Ubiquitina/metabolismo , Ubiquitinação/efeitos dos fármacos
15.
PLoS Genet ; 12(10): e1006362, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27736876

RESUMO

In response to environmental and physiological changes, the synapse manifests plasticity while simultaneously maintains homeostasis. Here, we analyzed mutant synapses of henji, also known as dbo, at the Drosophila neuromuscular junction (NMJ). In henji mutants, NMJ growth is defective with appearance of satellite boutons. Transmission electron microscopy analysis indicates that the synaptic membrane region is expanded. The postsynaptic density (PSD) houses glutamate receptors GluRIIA and GluRIIB, which have distinct transmission properties. In henji mutants, GluRIIA abundance is upregulated but that of GluRIIB is not. Electrophysiological results also support a GluR compositional shift towards a higher IIA/IIB ratio at henji NMJs. Strikingly, dPAK, a positive regulator for GluRIIA synaptic localization, accumulates at the henji PSD. Reducing the dpak gene dosage suppresses satellite boutons and GluRIIA accumulation at henji NMJs. In addition, dPAK associated with Henji through the Kelch repeats which is the domain essential for Henji localization and function at postsynapses. We propose that Henji acts at postsynapses to restrict both presynaptic bouton growth and postsynaptic GluRIIA abundance by modulating dPAK.


Assuntos
Proteínas de Drosophila/genética , Junção Neuromuscular/genética , Receptores de Glutamato/genética , Receptores Ionotrópicos de Glutamato/genética , Sinapses/genética , Quinases Ativadas por p21/genética , Animais , Moléculas de Adesão Celular Neuronais/genética , Drosophila melanogaster/genética , Drosophila melanogaster/ultraestrutura , Repetição Kelch/genética , Microscopia Eletrônica de Transmissão , Junção Neuromuscular/ultraestrutura , Terminações Pré-Sinápticas/metabolismo , Sinapses/ultraestrutura , Transmissão Sináptica/genética
16.
Nat Neurosci ; 19(11): 1513-1522, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27595386

RESUMO

Cortico-basal ganglia circuits are critical for speech and language and are implicated in autism spectrum disorder, in which language function can be severely affected. We demonstrate that in the mouse striatum, the gene Foxp2 negatively interacts with the synapse suppressor gene Mef2c. We present causal evidence that Mef2c inhibition by Foxp2 in neonatal mouse striatum controls synaptogenesis of corticostriatal inputs and vocalization in neonates. Mef2c suppresses corticostriatal synapse formation and striatal spinogenesis, but can itself be repressed by Foxp2 through direct DNA binding. Foxp2 deletion de-represses Mef2c, and both intrastriatal and global decrease of Mef2c rescue vocalization and striatal spinogenesis defects of Foxp2-deletion mutants. These findings suggest that Foxp2-Mef2C signaling is critical to corticostriatal circuit formation. If found in humans, such signaling defects could contribute to a range of neurologic and neuropsychiatric disorders.


Assuntos
Transtorno do Espectro Autista/genética , Fatores de Transcrição Forkhead/metabolismo , Vias Neurais/metabolismo , Proteínas Repressoras/metabolismo , Vocalização Animal/fisiologia , Animais , Gânglios da Base/metabolismo , Comunicação , Corpo Estriado/metabolismo , Aprendizagem/fisiologia , Fatores de Transcrição MEF2/genética , Camundongos Transgênicos
17.
Elife ; 52016 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-27504967

RESUMO

Studying the auditory system of the fruit fly can reveal how hearing works in mammals.


Assuntos
Proteínas de Drosophila , Síndromes de Usher , Animais , Drosophila , Audição , Mamíferos , Ubiquitina-Proteína Ligases
18.
Hum Mol Genet ; 25(10): 1965-1978, 2016 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-26931464

RESUMO

Parkinson's disease (PD) is a progressive neurodegenerative disorder that lacks a disease-modifying therapy. Leucine-rich repeat kinase 2 (LRRK2) was implicated as the most common genetic cause of PD. We previously established a LRRK2-G2019S Drosophila model that displayed the crucial phenotypes of LRRK2 parkinsonism. Here, we used a two-step approach to identify compounds from the FDA-approved licensed drug library that could suppress neurite degeneration in LRRK2-G2019S parkinsonism. Of 640 compounds, 29 rescued neurite degeneration phenotypes and 3 restored motor disability and dopaminergic neuron loss in aged LRRK2-G2019S flies. Of these three drugs, lovastatin had the highest lipophilicity, which facilitated crossing the blood-brain barrier. In LRRK2-G2019S knock-in mice and stably transfected human dopaminergic cells, lovastatin significantly rescued neurite degeneration in a dose-dependent manner, within a range of 0.05-0.1 µm The beneficial effect of lovastatin was exerted by activating anti-apoptotic Akt/Nrf signaling and decreasing caspase 3 levels. We also observed that lovastatin inhibited GSK3ß activity, a kinase downstream of Akt, by up-regulating GSK3ß (Ser9) phosphorylation. This inhibition subsequently decreased tau phosphorylation, which was linked to neuronal cytoskeleton instability. Conversely, pre-treatment with the Akt inhibitor, A6730, blocked the lovastatin-induced neuroprotective effect. The rescuing effects of lovastatin in dendritic arborization of LRRK2-G2019S neurons were abolished by co-expressing either a mutant allele of Akt (Akt104226) or a constitutively active form of GSK3ß (sggS9A). Our findings demonstrated that lovastatin restored LRRK2-G2019S neurite degeneration by augmenting Akt/NRF2 pathway and inhibiting downstream GSK3ß activity, which decreased phospho-tau levels. We suggested that lovastatin is a potential disease-modifying agent for LRRK2-G2019S parkinsonism.


Assuntos
Glicogênio Sintase Quinase 3 beta/genética , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/genética , Degeneração Neural/tratamento farmacológico , Doença de Parkinson/genética , Proteínas Proto-Oncogênicas c-akt/genética , Serina Endopeptidases/genética , Animais , Animais Geneticamente Modificados , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/patologia , Drosophila melanogaster/genética , Glicogênio Sintase Quinase 3 beta/antagonistas & inibidores , Glicogênio Sintase Quinase 3 beta/biossíntese , Humanos , Lovastatina/administração & dosagem , Camundongos , Neurônios Motores/efeitos dos fármacos , Neurônios Motores/patologia , Mutação , Degeneração Neural/genética , Degeneração Neural/patologia , Neuritos/efeitos dos fármacos , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/patologia , Transtornos Parkinsonianos/tratamento farmacológico , Transtornos Parkinsonianos/genética , Transtornos Parkinsonianos/fisiopatologia , Transdução de Sinais/efeitos dos fármacos
19.
J Cell Biol ; 210(3): 471-83, 2015 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-26216903

RESUMO

Constructing the dendritic arbor of neurons requires dynamic movements of Golgi outposts (GOPs), the prominent component in the dendritic secretory pathway. GOPs move toward dendritic ends (anterograde) or cell bodies (retrograde), whereas most of them remain stationary. Here, we show that Leucine-rich repeat kinase (Lrrk), the Drosophila melanogaster homologue of Parkinson's disease-associated Lrrk2, regulates GOP dynamics in dendrites. Lrrk localized at stationary GOPs in dendrites and suppressed GOP movement. In Lrrk loss-of-function mutants, anterograde movement of GOPs was enhanced, whereas Lrrk overexpression increased the pool size of stationary GOPs. Lrrk interacted with the golgin Lava lamp and inhibited the interaction between Lva and dynein heavy chain, thus disrupting the recruitment of dynein to Golgi membranes. Whereas overexpression of kinase-dead Lrrk caused dominant-negative effects on GOP dynamics, overexpression of the human LRRK2 mutant G2019S with augmented kinase activity promoted retrograde movement. Our study reveals a pathogenic pathway for LRRK2 mutations causing dendrite degeneration.


Assuntos
Dendritos/metabolismo , Proteínas de Drosophila/metabolismo , Complexo de Golgi/metabolismo , Proteínas de Membrana/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Animais Geneticamente Modificados , Linhagem Celular , Proteínas de Drosophila/biossíntese , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Dineínas/metabolismo , Proteínas Serina-Treonina Quinases/biossíntese , Proteínas Serina-Treonina Quinases/genética , Transporte Proteico/genética
20.
PLoS Genet ; 10(11): e1004760, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25393278

RESUMO

During development, neural competence is conferred and maintained by integrating spatial and temporal regulations. The Drosophila sensory bristles that detect mechanical and chemical stimulations are arranged in stereotypical positions. The anterior wing margin (AWM) is arrayed with neuron-innervated sensory bristles, while posterior wing margin (PWM) bristles are non-innervated. We found that the COP9 signalosome (CSN) suppresses the neural competence of non-innervated bristles at the PWM. In CSN mutants, PWM bristles are transformed into neuron-innervated, which is attributed to sustained expression of the neural-determining factor Senseless (Sens). The CSN suppresses Sens through repression of the ecdysone signaling target gene broad (br) that encodes the BR-Z1 transcription factor to activate sens expression. Strikingly, CSN suppression of BR-Z1 is initiated at the prepupa-to-pupa transition, leading to Sens downregulation, and termination of the neural competence of PWM bristles. The role of ecdysone signaling to repress br after the prepupa-to-pupa transition is distinct from its conventional role in activation, and requires CSN deneddylating activity and multiple cullins, the major substrates of deneddylation. Several CSN subunits physically associate with ecdysone receptors to represses br at the transcriptional level. We propose a model in which nuclear hormone receptors cooperate with the deneddylation machinery to temporally shutdown downstream target gene expression, conferring a spatial restriction on neural competence at the PWM.


Assuntos
Proteínas de Drosophila/genética , Complexos Multiproteicos/genética , Proteínas Nucleares/genética , Peptídeo Hidrolases/genética , Fatores de Transcrição/genética , Asas de Animais/crescimento & desenvolvimento , Animais , Complexo do Signalossomo COP9 , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Ecdisona/genética , Ecdisona/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Complexos Multiproteicos/metabolismo , Mutação , Neurônios/metabolismo , Proteínas Nucleares/metabolismo , Peptídeo Hidrolases/metabolismo , Fatores de Transcrição/metabolismo
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