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1.
Neuron ; 97(4): 823-835.e8, 2018 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-29398363

RESUMO

Synaptic dysfunction is an early pathological feature of neurodegenerative diseases associated with Tau, including Alzheimer's disease. Interfering with early synaptic dysfunction may be therapeutically beneficial to prevent cognitive decline and disease progression, but the mechanisms underlying synaptic defects associated with Tau are unclear. In disease conditions, Tau mislocalizes into pre- and postsynaptic compartments; here we show that, under pathological conditions, Tau binds to presynaptic vesicles in Alzheimer's disease patient brain. We define that the binding of Tau to synaptic vesicles is mediated by the transmembrane vesicle protein Synaptogyrin-3. In fly and mouse models of Tauopathy, reduction of Synaptogyrin-3 prevents the association of presynaptic Tau with vesicles, alleviates Tau-induced defects in vesicle mobility, and restores neurotransmitter release. This work therefore identifies Synaptogyrin-3 as the binding partner of Tau on synaptic vesicles, revealing a new presynapse-specific Tau interactor, which may contribute to early synaptic dysfunction in neurodegenerative diseases associated with Tau.


Assuntos
Doença de Alzheimer/metabolismo , Terminações Pré-Sinápticas/metabolismo , Vesículas Sinápticas/metabolismo , Sinaptogirinas/metabolismo , Proteínas tau/metabolismo , Animais , Modelos Animais de Doenças , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Feminino , Hipocampo/metabolismo , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurônios/metabolismo , Cultura Primária de Células , Tauopatias/metabolismo
2.
EMBO J ; 36(10): 1392-1411, 2017 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-28331029

RESUMO

Presynaptic terminals are metabolically active and accrue damage through continuous vesicle cycling. How synapses locally regulate protein homeostasis is poorly understood. We show that the presynaptic lipid phosphatase synaptojanin is required for macroautophagy, and this role is inhibited by the Parkinson's disease mutation R258Q. Synaptojanin drives synaptic endocytosis by dephosphorylating PI(4,5)P2, but this function appears normal in SynaptojaninRQ knock-in flies. Instead, R258Q affects the synaptojanin SAC1 domain that dephosphorylates PI(3)P and PI(3,5)P2, two lipids found in autophagosomal membranes. Using advanced imaging, we show that SynaptojaninRQ mutants accumulate the PI(3)P/PI(3,5)P2-binding protein Atg18a on nascent synaptic autophagosomes, blocking autophagosome maturation at fly synapses and in neurites of human patient induced pluripotent stem cell-derived neurons. Additionally, we observe neurodegeneration, including dopaminergic neuron loss, in SynaptojaninRQ flies. Thus, synaptojanin is essential for macroautophagy within presynaptic terminals, coupling protein turnover with synaptic vesicle cycling and linking presynaptic-specific autophagy defects to Parkinson's disease.


Assuntos
Autofagossomos/metabolismo , Autofagia , Proteínas do Tecido Nervoso/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Terminações Pré-Sinápticas/enzimologia , Terminações Pré-Sinápticas/metabolismo , Substituição de Aminoácidos , Animais , Proteínas Relacionadas à Autofagia/análise , Células Cultivadas , Drosophila , Humanos , Proteínas de Membrana/análise , Mutação de Sentido Incorreto , Proteínas do Tecido Nervoso/genética , Doença de Parkinson/patologia , Fosfatos de Fosfatidilinositol/metabolismo , Monoéster Fosfórico Hidrolases/genética
3.
Elife ; 42015 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-26701908

RESUMO

Cystic fibrosis (CF) is caused by mutations in CF transmembrane conductance regulator (CFTR). The most frequent mutation (F508del-CFTR) results in altered proteostasis, that is, in the misfolding and intracellular degradation of the protein. The F508del-CFTR proteostasis machinery and its homeostatic regulation are well studied, while the question whether 'classical' signalling pathways and phosphorylation cascades might control proteostasis remains barely explored. Here, we have unravelled signalling cascades acting selectively on the F508del-CFTR folding-trafficking defects by analysing the mechanisms of action of F508del-CFTR proteostasis regulator drugs through an approach based on transcriptional profiling followed by deconvolution of their gene signatures. Targeting multiple components of these signalling pathways resulted in potent and specific correction of F508del-CFTR proteostasis and in synergy with pharmacochaperones. These results provide new insights into the physiology of cellular proteostasis and a rational basis for developing effective pharmacological correctors of the F508del-CFTR defect.


Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Fibrose Cística/genética , Deficiências na Proteostase/genética , Transdução de Sinais , Linhagem Celular , Inibidores Enzimáticos/metabolismo , Perfilação da Expressão Gênica , Humanos , Dobramento de Proteína , Proteólise , Deleção de Sequência
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