Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Biophys J ; 122(18): 3678-3689, 2023 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-37218133

RESUMO

Directed transport of cellular components is often dependent on the processive movements of cytoskeletal motors. Myosin 2 motors predominantly engage actin filaments of opposing orientation to drive contractile events and are therefore not traditionally viewed as processive. However, recent in vitro experiments with purified nonmuscle myosin 2 (NM2) demonstrated myosin 2 filaments could move processively. Here, we establish processivity as a cellular property of NM2. Processive runs in central nervous system-derived CAD cells are most apparent on bundled actin in protrusions that terminate at the leading edge. We find that processive velocities in vivo are consistent with in vitro measurements. NM2 makes these processive runs in its filamentous form against lamellipodia retrograde flow, though anterograde movement can still occur in the absence of actin dynamics. Comparing the processivity of NM2 isoforms, we find that NM2A moves slightly faster than NM2B. Finally, we demonstrate that this is not a cell-specific property, as we observe processive-like movements of NM2 in the lamella and subnuclear stress fibers of fibroblasts. Collectively, these observations further broaden NM2 functionality and the biological processes in which the already ubiquitous motor can contribute.


Assuntos
Actinas , Citoesqueleto , Actinas/fisiologia , Citoesqueleto de Actina , Proteínas do Citoesqueleto , Miosina Tipo II
2.
bioRxiv ; 2023 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-36865321

RESUMO

Directed transport of cellular components is often dependent on the processive movements of cytoskeletal motors. Myosin 2 motors predominantly engage actin filaments of opposing orientation to drive contractile events, and are therefore not traditionally viewed as processive. However, recent in vitro experiments with purified non-muscle myosin 2 (NM2) demonstrated myosin 2 filaments could move processively. Here, we establish processivity as a cellular property of NM2. Processive runs in central nervous system-derived CAD cells are most apparent as processive movements on bundled actin in protrusions that terminate at the leading edge. We find that processive velocities in vivo are consistent with in vitro measurements. NM2 makes these processive runs in its filamentous form against lamellipodia retrograde flow, though anterograde movement can still occur in the absence of actin dynamics. Comparing the processivity of NM2 isoforms, we find that NM2A moves slightly faster than NM2B. Finally, we demonstrate that this is not a cell-specific property, as we observe processive-like movements of NM2 in the lamella and subnuclear stress fibers of fibroblasts. Collectively, these observations further broaden NM2 functionality and the biological processes in which the already ubiquitous motor can contribute.

3.
Nat Neurosci ; 22(3): 386-400, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30742117

RESUMO

Fragile X syndrome results from a loss of the RNA-binding protein fragile X mental retardation protein (FMRP). How FMRP regulates neuronal development and function remains unclear. Here we show that FMRP-deficient immature neurons exhibit impaired dendritic maturation, altered expression of mitochondrial genes, fragmented mitochondria, impaired mitochondrial function, and increased oxidative stress. Enhancing mitochondrial fusion partially rescued dendritic abnormalities in FMRP-deficient immature neurons. We show that FMRP deficiency leads to reduced Htt mRNA and protein levels and that HTT mediates FMRP regulation of mitochondrial fusion and dendritic maturation. Mice with hippocampal Htt knockdown and Fmr1-knockout mice showed similar behavioral deficits that could be rescued by treatment with a mitochondrial fusion compound. Our data unveil mitochondrial dysfunction as a contributor to the impaired dendritic maturation of FMRP-deficient neurons and suggest a role for interactions between FMRP and HTT in the pathogenesis of fragile X syndrome.


Assuntos
Dendritos/metabolismo , Giro Denteado/metabolismo , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Proteína Huntingtina/metabolismo , Dinâmica Mitocondrial , Animais , Giro Denteado/crescimento & desenvolvimento , Feminino , Proteína do X Frágil da Deficiência Intelectual/genética , Técnicas de Silenciamento de Genes , Genes Mitocondriais , Proteína Huntingtina/genética , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estresse Oxidativo
4.
Hum Mol Genet ; 28(2): 245-257, 2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30277526

RESUMO

Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations or deletions in Methyl-CpG-binding Protein 2 (MeCP2), a brain-enriched transcriptional regulator. MeCP2 is highly expressed during neuronal maturation and its deficiency results in impaired dendritic morphogenesis and reduced dendritic spine numbers in developing neurons. However, whether MeCP2 deficiency impacts the integration of new neurons has not been directly assessed. In this study, we developed a modified rabies virus-mediated monosynaptic retrograde tracing method to interrogate presynaptic integration of MeCP2-deficient new neurons born in the adult hippocampus, a region with lifelong neurogenesis and plasticity. We found that selective deletion of MeCP2 in adult-born new neurons impaired their long-range connectivity to the cortex, whereas their connectivity within the local hippocampal circuits or with subcortical regions was not significantly affected. We further showed that knockdown of MeCP2 in primary hippocampal neurons also resulted in reduced network integration. Interestingly, (1-3) insulin-like growth factor-1 (IGF-1), a small peptide under clinical trial testing for RTT, rescued neuronal integration deficits of MeCP2-deficient neurons in vitro but not in vivo. In addition, (1-3) IGF-1 treatment corrected aberrant excitability and network synchrony of MeCP2-deficient hippocampal neurons. Our results indicate that MeCP2 is essential for immature neurons to establish appropriate network connectivity.


Assuntos
Proteína 2 de Ligação a Metil-CpG/fisiologia , Rede Nervosa , Neurogênese , Neurônios/citologia , Animais , Células Cultivadas , Dendritos , Hipocampo/citologia , Hipocampo/efeitos dos fármacos , Fator de Crescimento Insulin-Like I/farmacologia , Masculino , Proteína 2 de Ligação a Metil-CpG/deficiência , Proteína 2 de Ligação a Metil-CpG/genética , Camundongos , Camundongos Endogâmicos C57BL , Técnicas de Rastreamento Neuroanatômico , Neurogênese/efeitos dos fármacos , Neurônios/metabolismo , Retroviridae
5.
Proc Natl Acad Sci U S A ; 112(36): E4995-5004, 2015 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-26305964

RESUMO

The mammalian embryonic lethal abnormal vision (ELAV)-like protein HuD is a neuronal RNA-binding protein implicated in neuronal development, plasticity, and diseases. Although HuD has long been associated with neuronal development, the functions of HuD in neural stem cell differentiation and the underlying mechanisms have gone largely unexplored. Here we show that HuD promotes neuronal differentiation of neural stem/progenitor cells (NSCs) in the adult subventricular zone by stabilizing the mRNA of special adenine-thymine (AT)-rich DNA-binding protein 1 (SATB1), a critical transcriptional regulator in neurodevelopment. We find that SATB1 deficiency impairs the neuronal differentiation of NSCs, whereas SATB1 overexpression rescues the neuronal differentiation phenotypes resulting from HuD deficiency. Interestingly, we also discover that SATB1 is a transcriptional activator of HuD during NSC neuronal differentiation. In addition, we demonstrate that NeuroD1, a neuronal master regulator, is a direct downstream target of SATB1. Therefore, HuD and SATB1 form a positive regulatory loop that enhances NeuroD1 transcription and subsequent neuronal differentiation. Our results here reveal a novel positive feedback network between an RNA-binding protein and a transcription factor that plays critical regulatory roles in neurogenesis.


Assuntos
Proteína Semelhante a ELAV 4/metabolismo , Retroalimentação Fisiológica , Proteínas de Ligação à Região de Interação com a Matriz/metabolismo , Neurogênese , Animais , Sequência de Bases , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Sítios de Ligação/genética , Western Blotting , Diferenciação Celular , Células Cultivadas , Proteína Semelhante a ELAV 4/genética , Ventrículos Laterais/citologia , Ventrículos Laterais/metabolismo , Masculino , Proteínas de Ligação à Região de Interação com a Matriz/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microscopia Confocal , Dados de Sequência Molecular , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Bulbo Olfatório/citologia , Bulbo Olfatório/metabolismo , Ligação Proteica , Interferência de RNA , Estabilidade de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...