Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.874
Filtrar
1.
Neuron ; 109(18): 2884-2901.e7, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34534453

RESUMO

In non-neuronal cells, clathrin has established roles in endocytosis, with clathrin cages enclosing plasma membrane infoldings, followed by rapid disassembly and reuse of monomers. However, in neurons, clathrin is conveyed in slow axonal transport over days to weeks, and the underlying transport/targeting mechanisms, mobile cargo structures, and even its precise presynaptic localization and physiologic role are unclear. Combining live imaging, photobleaching/conversion, mass spectrometry, electron microscopy, and super-resolution imaging, we found that unlike in dendrites, where clathrin cages rapidly assemble and disassemble, in axons, clathrin and related proteins organize into stable "transport packets" that are unrelated to endocytosis and move intermittently on microtubules, generating an overall slow anterograde flow. At synapses, multiple clathrin packets abut synaptic vesicle (SV) clusters, and clathrin packets also exchange between synaptic boutons in a microtubule-dependent "superpool." Within synaptic boundaries, clathrin is surprisingly dynamic, continuously exchanging between local clathrin assemblies, and its depletion impairs SV recycling. Our data provide a conceptual framework for understanding clathrin trafficking and presynaptic targeting that has functional implications.


Assuntos
Transporte Axonal/fisiologia , Vesículas Revestidas por Clatrina/metabolismo , Clatrina/metabolismo , Hipocampo/metabolismo , Sinapses/metabolismo , Animais , Animais Recém-Nascidos , Células Cultivadas , Clatrina/química , Vesículas Revestidas por Clatrina/química , Hipocampo/química , Hipocampo/citologia , Camundongos , Transporte Proteico/fisiologia , Ratos , Ratos Wistar , Sinapses/química , Imagem com Lapso de Tempo/métodos
2.
Molecules ; 26(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34361779

RESUMO

Delivering nucleic acids into the endothelium has great potential in treating vascular diseases. However, endothelial cells, which line the vasculature, are considered as sensitive in nature and hard to transfect. Low transfection efficacies in endothelial cells limit their potential therapeutic applications. Towards improving the transfection efficiency, we made an effort to understand the internalization of lipoplexes into the cells, which is the first and most critical step in nucleic acid transfections. In this study, we demonstrated that the transient modulation of caveolae/lipid rafts mediated endocytosis with the cholesterol-sequestrating agents, nystatin, filipin III, and siRNA against Cav-1, which significantly increased the transfection properties of cationic lipid-(2-hydroxy-N-methyl-N,N-bis(2-tetradecanamidoethyl)ethanaminium chloride), namely, amide liposomes in combination with 1,2-Dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) (AD Liposomes) in liver sinusoidal endothelial cells (SK-Hep1). In particular, nystatin was found to be highly effective with 2-3-fold enhanced transfection efficacy when compared with amide liposomes in combination with Cholesterol (AC), by switching lipoplex internalization predominantly through clathrin-mediated endocytosis and macropinocytosis.


Assuntos
Cavéolas/efeitos dos fármacos , Colesterol/química , Células Endoteliais/efeitos dos fármacos , Lipossomos/química , Microdomínios da Membrana/efeitos dos fármacos , Transfecção/métodos , Animais , Cavéolas/química , Cavéolas/metabolismo , Caveolina 1/antagonistas & inibidores , Caveolina 1/genética , Caveolina 1/metabolismo , Linhagem Celular Transformada , Colesterol/metabolismo , Clatrina/metabolismo , DNA/química , DNA/metabolismo , Endocitose/efeitos dos fármacos , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Filipina/química , Filipina/farmacologia , Expressão Gênica , Lipossomos/metabolismo , Microdomínios da Membrana/química , Microdomínios da Membrana/metabolismo , Nistatina/química , Nistatina/farmacologia , Fosfatidiletanolaminas/química , Fosfatidiletanolaminas/farmacologia , Pinocitose/efeitos dos fármacos , Plasmídeos/química , Plasmídeos/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Ratos
3.
Nat Commun ; 12(1): 5073, 2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34417467

RESUMO

The contents of numerous membrane lipids change upon ageing. However, it is unknown whether and how any of these changes are causally linked to lifespan regulation. Acyl chains contribute to the functional specificity of membrane lipids. In this study, working with C. elegans, we identified an acyl chain-specific sphingolipid, C22 glucosylceramide, as a longevity metabolite. Germline deficiency, a conserved lifespan-extending paradigm, induces somatic expression of the fatty acid elongase ELO-3, and behenic acid (22:0) generated by ELO-3 is incorporated into glucosylceramide for lifespan regulation. Mechanistically, C22 glucosylceramide is required for the membrane localization of clathrin, a protein that regulates membrane budding. The reduction in C22 glucosylceramide impairs the clathrin-dependent autophagic lysosome reformation, which subsequently leads to TOR activation and longevity suppression. These findings reveal a mechanistic link between membrane lipids and ageing and suggest a model of lifespan regulation by fatty acid-mediated membrane configuration.


Assuntos
Caenorhabditis elegans/fisiologia , Ácidos Graxos não Esterificados/metabolismo , Glicoesfingolipídeos/metabolismo , Homeostase , Longevidade/fisiologia , Lisossomos/metabolismo , Animais , Proteínas de Caenorhabditis elegans/metabolismo , Ceramidas/metabolismo , Colesterol/metabolismo , Clatrina/metabolismo , Mutação em Linhagem Germinativa/genética , Proteínas de Fluorescência Verde/metabolismo , Larva/metabolismo , Modelos Biológicos , Interferência de RNA , Estresse Fisiológico
4.
Molecules ; 26(11)2021 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-34204150

RESUMO

The purpose of this study was to develop mixed polymeric micelles with high drug loading capacity to improve the oral bioavailability of icaritin with Soluplus® and Poloxamer 407 using a creative acid-base shift (ABS) method, which exhibits the advantages of exclusion of organic solvents, high drug loading and ease of scaling-up. The feasibility of the ABS method was successfully demonstrated by studies of icaritin-loaded polymeric micelles (IPMs). The prepared IPMs were characterized to have a spherical shape with a size of 72.74 ± 0.51 nm, and 13.18% drug loading content. In vitro release tests confirmed the faster release of icaritin from IPMs compared to an oil suspension. Furthermore, bioavailability of icaritin in IPMs in beagle dogs displayed a 14.9-fold increase when compared with the oil suspension. Transcellular transport studies of IPMs across Caco-2 cell monolayers confirmed that the IPMs were endocytosed in their intact forms through macropinocytosis, clathrin-, and caveolae-mediated pathways. In conclusion, the results suggested that the mixed micelles of Soluplus® and Poloxamer 407 could be a feasible drug delivery system to enhance oral bioavailability of icaritin, and the ABS method might be a promising technology for the preparation of polymeric micelles to encapsulate poorly water-soluble weakly acidic and alkaline drugs.


Assuntos
Flavonoides/administração & dosagem , Poloxâmero/química , Polietilenoglicóis/química , Polivinil/química , Transdução de Sinais/efeitos dos fármacos , Administração Oral , Animais , Disponibilidade Biológica , Células CACO-2 , Cavéolas/metabolismo , Clatrina/metabolismo , Cães , Estudos de Viabilidade , Flavonoides/síntese química , Flavonoides/farmacocinética , Humanos , Masculino , Micelas , Nanopartículas , Tamanho da Partícula
5.
Int J Mol Sci ; 22(13)2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34209489

RESUMO

The endocytosis of ligand-bound receptors and their eventual recycling to the plasma membrane (PM) are processes that have an influence on signalling activity and therefore on many cell functions, including migration and proliferation. Like other tyrosine kinase receptors (TKR), the insulin receptor (INSR) has been shown to be endocytosed by clathrin-dependent and -independent mechanisms. Once at the early endosome (EE), the sorting of the receptor, either to the late endosome (LE) for degradation or back to the PM through slow or fast recycling pathways, will determine the intensity and duration of insulin effects. Both the endocytic and the endosomic pathways are regulated by many proteins, the Arf and Rab families of small GTPases being some of the most relevant. Here, we argue for a specific role for the slow recycling route, whilst we review the main molecular mechanisms involved in INSR endocytosis, sorting and recycling, as well as their possible role in cell functions.


Assuntos
Endossomos/metabolismo , Receptor de Insulina/metabolismo , Animais , Proteínas de Transporte , Membrana Celular/metabolismo , Movimento Celular , Proliferação de Células , Clatrina/metabolismo , Endocitose , Humanos , Lisossomos , Ligação Proteica , Transporte Proteico , Receptor de Insulina/agonistas , Vesículas Transportadoras/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo
6.
Development ; 148(14)2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34269385

RESUMO

Fertilization triggers significant cellular remodeling through the oocyte-to-embryo transition. In this transition, the ubiquitin-proteasome system and autophagy are essential for the degradation of maternal components; however, the significance of degradation of cell surface components remains unknown. In this study, we show that multiple maternal plasma membrane proteins, such as the glycine transporter GlyT1a, are selectively internalized from the plasma membrane to endosomes in mouse embryos by the late two-cell stage and then transported to lysosomes for degradation at the later stages. During this process, large amounts of ubiquitylated proteins accumulated on endosomes. Furthermore, the degradation of GlyT1a with mutations in potential ubiquitylation sites was delayed, suggesting that ubiquitylation may be involved in GlyT1a degradation. The clathrin inhibitor blocked GlyT1a internalization. Strikingly, the protein kinase C (PKC) activator triggered the heterochronic internalization of GlyT1a; the PKC inhibitor markedly blocked GlyT1a endocytosis. Lastly, clathrin inhibition completely blocked embryogenesis at the two-cell stage and inhibited cell division after the four-cell stage. These findings demonstrate that PKC-dependent clathrin-mediated endocytosis is essential for the selective degradation of maternal membrane proteins during oocyte-to-embryo transition and early embryogenesis.


Assuntos
Clatrina/metabolismo , Desenvolvimento Embrionário/fisiologia , Endocitose/fisiologia , Proteínas de Membrana/metabolismo , Animais , Membrana Celular/metabolismo , Embrião de Mamíferos , Endossomos/metabolismo , Feminino , Fertilização , Proteínas da Membrana Plasmática de Transporte de Glicina , Masculino , Camundongos , Oócitos , Proteína Quinase C , Ubiquitina/metabolismo , Ubiquitinação
7.
PLoS Pathog ; 17(7): e1009706, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34252168

RESUMO

Many viruses utilize the host endo-lysosomal network for infection. Tracing the endocytic itinerary of SARS-CoV-2 can provide insights into viral trafficking and aid in designing new therapeutic strategies. Here, we demonstrate that the receptor binding domain (RBD) of SARS-CoV-2 spike protein is internalized via the pH-dependent CLIC/GEEC (CG) endocytic pathway in human gastric-adenocarcinoma (AGS) cells expressing undetectable levels of ACE2. Ectopic expression of ACE2 (AGS-ACE2) results in RBD traffic via both CG and clathrin-mediated endocytosis. Endosomal acidification inhibitors like BafilomycinA1 and NH4Cl, which inhibit the CG pathway, reduce the uptake of RBD and impede Spike-pseudoviral infection in both AGS and AGS-ACE2 cells. The inhibition by BafilomycinA1 was found to be distinct from Chloroquine which neither affects RBD uptake nor alters endosomal pH, yet attenuates Spike-pseudovirus entry. By screening a subset of FDA-approved inhibitors for functionality similar to BafilomycinA1, we identified Niclosamide as a SARS-CoV-2 entry inhibitor. Further validation using a clinical isolate of SARS-CoV-2 in AGS-ACE2 and Vero cells confirmed its antiviral effect. We propose that Niclosamide, and other drugs which neutralize endosomal pH as well as inhibit the endocytic uptake, could provide broader applicability in subverting infection of viruses entering host cells via a pH-dependent endocytic pathway.


Assuntos
COVID-19/tratamento farmacológico , COVID-19/virologia , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/patogenicidade , Internalização do Vírus/efeitos dos fármacos , Cloreto de Amônio/farmacologia , Enzima de Conversão de Angiotensina 2/genética , Enzima de Conversão de Angiotensina 2/fisiologia , Animais , Antivirais/administração & dosagem , Antivirais/farmacologia , Linhagem Celular , Chlorocebus aethiops , Cloroquina/farmacologia , Clatrina/metabolismo , Sinergismo Farmacológico , Endocitose/efeitos dos fármacos , Endocitose/fisiologia , Endossomos/efeitos dos fármacos , Endossomos/metabolismo , Humanos , Concentração de Íons de Hidrogênio/efeitos dos fármacos , Hidroxicloroquina/administração & dosagem , Macrolídeos/farmacologia , Niclosamida/administração & dosagem , Niclosamida/farmacologia , Ligação Proteica/efeitos dos fármacos , Domínios Proteicos , SARS-CoV-2/fisiologia , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/fisiologia , Células Vero
8.
Molecules ; 26(9)2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-34067155

RESUMO

The aim of this study was to evaluate the involvement of nanoparticles prepared from Allium cepa L. as anti-inflammatory agents. In the present study, we identified nanoparticles from Allium cepa L. using the ultracentrifugation exosome purification method. The nanoparticles were referred to as 17,000× g and 200,000× g precipitates, and they contained quercetins, proteins, lipids, and small-sized RNA. The nanoparticles inhibited nitric oxide production from lipopolysaccharide (LPS)-stimulated RAW264 cells without cytotoxic properties. Cellular incorporation was confirmed by laser microscopic observation after PKH26 staining. The inhibition of caveolae-dependent endocytosis and macropinocytosis significantly prevented the incorporation of the nanoparticles but had no effect on the inhibition of nitric oxide in RAW264 cells. Collectively, the identified nanoparticles were capable of inhibiting the LPS response via extracellular mechanisms. Taken together, the way of consuming Allium cepa L. without collapsing the nanoparticles is expected to provide an efficient anti-inflammatory effect.


Assuntos
Endocitose , Espaço Intracelular/metabolismo , Nanopartículas/química , Nitratos/metabolismo , Cebolas/química , Animais , Clatrina/metabolismo , Lipopolissacarídeos , Camundongos , Óxido Nítrico/biossíntese , Quercetina/análise , Células RAW 264.7
9.
Immunology ; 164(1): 106-119, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33960403

RESUMO

CTLA-4 is an essential regulator of T-cell immune responses whose intracellular trafficking is a hallmark of its expression. Defects in CTLA-4 trafficking due to LRBA deficiency cause profound autoimmunity in humans. CTLA-4 rapidly internalizes via a clathrin-dependent pathway followed by poorly characterized recycling and degradation fates. Here, we explore the impact of manipulating Rab GTPases and LRBA on CTLA-4 expression to determine how these proteins affect CTLA-4 trafficking. We observe that CTLA-4 is distributed across several compartments marked by Rab5, Rab7 and Rab11 in both HeLa and Jurkat cells. Dominant negative (DN) inhibition of Rab5 resulted in increased surface CTLA-4 expression and reduced internalization and degradation. We also observed that constitutively active (CA) Rab11 increased, whereas DN Rab11 decreased CTLA-4 surface expression via an impact on CTLA-4 recycling, indicating CTLA-4 shares similarities with other recycling receptors such as EGFR. Additionally, we studied the impact of manipulating both LRBA and Rab11 on CTLA-4 trafficking. In Jurkat cells, LRBA deficiency was associated with markedly impaired CTLA-4 recycling and increased degradation that could not be corrected by expressing CA Rab11. Moreover LRBA deficiency reduced CTLA-4 colocalization with Rab11, suggesting that LRBA is upstream of Rab11. These results show that LRBA is required for effective CTLA-4 recycling by delivering CTLA-4 to Rab11 recycling compartments, and in its absence, CTLA-4 fails to recycle and undergoes degradation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Antígeno CTLA-4/metabolismo , Linfócitos T/imunologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Autoimunidade , Clatrina/metabolismo , Células HeLa , Humanos , Células Jurkat , Camundongos , Transporte Proteico , Proteólise , Transdução de Sinais , Proteínas rab de Ligação ao GTP , Proteínas rab5 de Ligação ao GTP/genética
10.
Nat Commun ; 12(1): 2889, 2021 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-34001871

RESUMO

During clathrin-mediated endocytosis, a complex and dynamic network of protein-membrane interactions cooperate to achieve membrane invagination. Throughout this process in yeast, endocytic coat adaptors, Sla2 and Ent1, must remain attached to the plasma membrane to transmit force from the actin cytoskeleton required for successful membrane invagination. Here, we present a cryo-EM structure of a 16-mer complex of the ANTH and ENTH membrane-binding domains from Sla2 and Ent1 bound to PIP2 that constitutes the anchor to the plasma membrane. Detailed in vitro and in vivo mutagenesis of the complex interfaces delineate the key interactions for complex formation and deficient cell growth phenotypes demonstrate its biological relevance. A hetero-tetrameric unit binds PIP2 molecules at the ANTH-ENTH interfaces and can form larger assemblies to contribute to membrane remodeling. Finally, a time-resolved small-angle X-ray scattering study of the interaction of these adaptor domains in vitro suggests that ANTH and ENTH domains have evolved to achieve a fast subsecond timescale assembly in the presence of PIP2 and do not require further proteins to form a stable complex. Together, these findings provide a molecular understanding of an essential piece in the molecular puzzle of clathrin-coated endocytic sites.


Assuntos
Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Clatrina/metabolismo , Proteínas do Citoesqueleto/metabolismo , Endocitose/fisiologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Proteínas Adaptadoras de Transporte Vesicular/genética , Proteínas Adaptadoras de Transporte Vesicular/ultraestrutura , Sítios de Ligação/genética , Membrana Celular/metabolismo , Microscopia Crioeletrônica , Proteínas do Citoesqueleto/química , Proteínas do Citoesqueleto/genética , Endocitose/genética , Modelos Moleculares , Multimerização Proteica , Estrutura Terciária de Proteína , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Transporte Vesicular/química , Proteínas de Transporte Vesicular/genética
11.
Nat Commun ; 12(1): 2149, 2021 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-33846319

RESUMO

Reovirus infection requires the concerted action of viral and host factors to promote cell entry. After interaction of reovirus attachment protein σ1 with cell-surface carbohydrates and proteinaceous receptors, additional host factors mediate virus internalization. In particular, ß1 integrin is required for endocytosis of reovirus virions following junctional adhesion molecule A (JAM-A) binding. While integrin-binding motifs in the surface-exposed region of reovirus capsid protein λ2 are thought to mediate integrin interaction, evidence for direct ß1 integrin-reovirus interactions and knowledge of how integrins function to mediate reovirus entry is lacking. Here, we use single-virus force spectroscopy and confocal microscopy to discover a direct interaction between reovirus and ß1 integrins. Comparison of interactions between reovirus disassembly intermediates as well as mutants and ß1 integrin show that λ2 is the integrin ligand. Finally, using fluidic force microscopy, we demonstrate a functional role for ß1 integrin interaction in promoting clathrin recruitment to cell-bound reovirus. Our study demonstrates a direct interaction between reovirus and ß1 integrins and offers insights into the mechanism of reovirus cell entry. These results provide new perspectives for the development of efficacious antiviral therapeutics and the engineering of improved viral gene delivery and oncolytic vectors.


Assuntos
Clatrina/metabolismo , Interações Hospedeiro-Patógeno , Integrina beta1/metabolismo , Reoviridae/fisiologia , Animais , Sítios de Ligação , Capsídeo/metabolismo , Cátions , Linhagem Celular , Membrana Celular/metabolismo , Endocitose , Cinética , Camundongos , Ácido N-Acetilneuramínico/metabolismo , Mutação Puntual/genética , Ligação Proteica , Termodinâmica , Proteínas Virais/metabolismo , Vírion/metabolismo
12.
Dev Cell ; 56(8): 1131-1146.e3, 2021 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-33823128

RESUMO

Clathrin-mediated endocytosis is the primary pathway for receptor and cargo internalization in eukaryotic cells. It is characterized by a polyhedral clathrin lattice that coats budding membranes. The mechanism and control of lattice assembly, curvature, and vesicle formation at the plasma membrane has been a matter of long-standing debate. Here, we use platinum replica and cryoelectron microscopy and tomography to present a structural framework of the pathway. We determine the shape and size parameters common to clathrin-mediated endocytosis. We show that clathrin sites maintain a constant surface area during curvature across multiple cell lines. Flat clathrin is present in all cells and spontaneously curves into coated pits without additional energy sources or recruited factors. Finally, we attribute curvature generation to loosely connected and pentagon-containing flat lattices that can rapidly curve when a flattening force is released. Together, these data present a universal mechanistic model of clathrin-mediated endocytosis.


Assuntos
Membrana Celular/fisiologia , Membrana Celular/ultraestrutura , Clatrina/metabolismo , Adesividade , Animais , Linhagem Celular , Colesterol/metabolismo , Microscopia Crioeletrônica , Humanos , Masculino , Camundongos , Modelos Biológicos , Ratos
13.
Nat Commun ; 12(1): 2424, 2021 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-33893293

RESUMO

Endocytosis mediates the cellular uptake of micronutrients and cell surface proteins. Fast Endophilin-mediated endocytosis, FEME, is not constitutively active but triggered upon receptor activation. High levels of growth factors induce spontaneous FEME, which can be suppressed upon serum starvation. This suggested a role for protein kinases in this growth factor receptor-mediated regulation. Using chemical and genetic inhibition, we find that Cdk5 and GSK3ß are negative regulators of FEME. They antagonize the binding of Endophilin to Dynamin-1 and to CRMP4, a Plexin A1 adaptor. This control is required for proper axon elongation, branching and growth cone formation in hippocampal neurons. The kinases also block the recruitment of Dynein onto FEME carriers by Bin1. As GSK3ß binds to Endophilin, it imposes a local regulation of FEME. Thus, Cdk5 and GSK3ß are key regulators of FEME, licensing cells for rapid uptake by the pathway only when their activity is low.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Quinase 5 Dependente de Ciclina/genética , Endocitose/genética , Glicogênio Sintase Quinase 3 beta/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Células Cultivadas , Clatrina/metabolismo , Quinase 5 Dependente de Ciclina/metabolismo , Dinamina I/genética , Dinamina I/metabolismo , Regulação da Expressão Gênica , Glicogênio Sintase Quinase 3 beta/metabolismo , Células HEK293 , Células HeLa , Hipocampo/citologia , Hipocampo/metabolismo , Humanos , Camundongos Endogâmicos C57BL , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Neurônios/metabolismo , Ligação Proteica , Interferência de RNA
14.
Nat Genet ; 53(5): 638-649, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33859415

RESUMO

A central question in the post-genomic era is how genes interact to form biological pathways. Measurements of gene dependency across hundreds of cell lines have been used to cluster genes into 'co-essential' pathways, but this approach has been limited by ubiquitous false positives. In the present study, we develop a statistical method that enables robust identification of gene co-essentiality and yields a genome-wide set of functional modules. This atlas recapitulates diverse pathways and protein complexes, and predicts the functions of 108 uncharacterized genes. Validating top predictions, we show that TMEM189 encodes plasmanylethanolamine desaturase, a key enzyme for plasmalogen synthesis. We also show that C15orf57 encodes a protein that binds the AP2 complex, localizes to clathrin-coated pits and enables efficient transferrin uptake. Finally, we provide an interactive webtool for the community to explore our results, which establish co-essentiality profiling as a powerful resource for biological pathway identification and discovery of new gene functions.


Assuntos
Redes Reguladoras de Genes , Genes , Genoma , Clatrina/metabolismo , Endocitose , Epigênese Genética , Regulação da Expressão Gênica , Células HeLa , Humanos , Anotação de Sequência Molecular , Neoplasias/genética , Plasmalogênios/biossíntese , Transdução de Sinais/genética
15.
Toxins (Basel) ; 13(3)2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33801329

RESUMO

With the growing diversity and complexity of diet, humans are at risk of simultaneous exposure to aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1), which are well-known contaminants in dairy and other agricultural products worldwide. The intestine represents the first barrier against external contaminants; however, evidence about the combined effect of AFB1 and AFM1 on intestinal integrity is lacking. In vivo, the serum biochemical parameters related to intestinal barrier function, ratio of villus height/crypt depth, and distribution pattern of claudin-1 and zonula occluden-1 were significantly affected in mice exposed to 0.3 mg/kg b.w. AFB1 and 3.0 mg/kg b.w. AFM1. In vitro results on differentiated Caco-2 cells showed that individual and combined AFB1 (0.5 and 4 µg/mL) and AFM1 (0.5 and 4 µg/mL) decreased cell viability and trans-epithelial electrical resistance values as well as increased paracellular permeability of fluorescein isothiocyanate-dextran in a dose-dependent manner. Furthermore, AFM1 aggravated AFB1-induced compromised intestinal barrier, as demonstrated by the down-regulation of tight junction proteins and their redistribution, particularly internalization. Adding the inhibitor chlorpromazine illustrated that clathrin-mediated endocytosis partially contributed to the compromised intestinal integrity. Synergistic and additive effects were the predominant interactions, suggesting that these toxins are likely to have negative effects on human health.


Assuntos
Aflatoxina B1/toxicidade , Aflatoxina M1/toxicidade , Clatrina/metabolismo , Endocitose , Absorção Intestinal/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Aflatoxina B1/metabolismo , Aflatoxina M1/metabolismo , Animais , Células CACO-2 , Sobrevivência Celular/efeitos dos fármacos , Impedância Elétrica , Humanos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Masculino , Camundongos Endogâmicos ICR , Permeabilidade , Proteínas de Junções Íntimas/metabolismo , Junções Íntimas/efeitos dos fármacos , Junções Íntimas/metabolismo , Junções Íntimas/patologia
16.
Development ; 148(5)2021 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-33692089

RESUMO

Animal steroid hormones initiate signaling by passive diffusion into cells and binding to their nuclear receptors to regulate gene expression. Animal steroid hormones can initiate signaling via G protein-coupled receptors (GPCRs); however, the underlying mechanisms are unclear. Here, we show that a newly discovered ecdysone-responsive GPCR, ErGPCR-3, transmits the steroid hormone 20-hydroxyecdysone (20E) signal by binding 20E and promoting its entry into cells in the lepidopteran insect Helicoverpa armigera Knockdown of ErGPCR-3 in larvae caused delayed and abnormal pupation, inhibited remodeling of the larval midgut and fat body, and repressed 20E-induced gene expression. Also, 20E induced both the interaction of ErGPCR-3 with G proteins and rapid intracellular increase in calcium, cAMP and protein phosphorylation. ErGPCR-3 was endocytosed by GPCR kinase 2-mediated phosphorylation, and interacted with ß-arrestin-1 and clathrin, to terminate 20E signaling under 20E induction. We found that 20E bound to ErGPCR-3 and induced the ErGPCR-3 homodimer to form a homotetramer, which increased 20E entry into cells. Our study revealed that homotetrameric ErGPCR-3 functions as a cell membrane receptor and increases 20E diffusion into cells to transmit the 20E signal and promote metamorphosis.


Assuntos
Ecdisterona/farmacologia , Proteínas de Insetos/metabolismo , Metamorfose Biológica/efeitos dos fármacos , Receptores Acoplados a Proteínas G/metabolismo , Animais , Clatrina/metabolismo , Ecdisterona/química , Ecdisterona/metabolismo , Endocitose , Proteínas de Insetos/antagonistas & inibidores , Proteínas de Insetos/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Mariposas/crescimento & desenvolvimento , Mariposas/metabolismo , Fosforilação/efeitos dos fármacos , Ligação Proteica , Multimerização Proteica/efeitos dos fármacos , Interferência de RNA , RNA de Cadeia Dupla/metabolismo , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Receptores Acoplados a Proteínas G/genética , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos
17.
Commun Biol ; 4(1): 373, 2021 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-33742129

RESUMO

Proximal tubular cells (PTCs) are crucial for maintaining renal homeostasis, and tubular injuries contribute to progression of diabetic kidney disease (DKD). However, the roles of visceral adipose tissue-derived serine protease inhibitor (vaspin) in the development of DKD is not known. We found vaspin maintains PTCs through ameliorating ER stress, autophagy impairment, and lysosome dysfunction in DKD. Vaspin-/- obese mice showed enlarged and leaky lysosomes in PTCs associated with increased apoptosis, and these abnormalities were also observed in the patients with DKD. During internalization into PTCs, vaspin formed a complex with heat shock protein family A (Hsp70) member 1 like (HSPA1L) as well as 78 kDa glucose-regulated protein (GRP78). Both vaspin-partners bind to clathrin heavy chain and involve in the endocytosis. Notably, albumin-overload enhanced extracellular release of HSPA1L and overexpression of HSPA1L dissolved organelle stresses, especially autophagy impairment. Thus, vapsin/HSPA1L-mediated pathways play critical roles in maintaining organellar function of PTCs in DKD.


Assuntos
Adipocinas/metabolismo , Nefropatias Diabéticas/metabolismo , Estresse do Retículo Endoplasmático , Proteínas de Choque Térmico HSP70/metabolismo , Túbulos Renais Proximais/metabolismo , Organelas/metabolismo , Serpinas/metabolismo , Adipocinas/genética , Animais , Apoptose , Autofagia , Linhagem Celular , Clatrina/metabolismo , Nefropatias Diabéticas/etiologia , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/patologia , Dieta Hiperlipídica , Modelos Animais de Doenças , Endocitose , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Inflamassomos/metabolismo , Túbulos Renais Proximais/patologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/complicações , Organelas/patologia , Ligação Proteica , Serpinas/genética , Transdução de Sinais
18.
mBio ; 12(2)2021 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-33785615

RESUMO

Coronaviruses (CoVs) have caused severe diseases in humans and animals. Endocytic pathways, such as clathrin-mediated endocytosis (CME) and caveolae-mediated endocytosis (CavME), play an important role for CoVs to penetrate the cell membrane barrier. In this study, a novel CoV entry manner is unraveled in which clathrin and caveolae can cooperatively mediate endocytosis of porcine epidemic diarrhea coronavirus (PEDV). Using multicolor live-cell imaging, the dynamics of the fluorescently labeled clathrin structures, caveolae structures, and PEDV were dissected. During CavME of PEDV, we found that clathrin structures can fuse with caveolae near the cell plasma membrane, and the average time of PEDV penetrating the cell membrane was within ∼3 min, exhibiting a rapid course of PEDV entry. Moreover, based on the dynamic recruitment of clathrin and caveolae structures and viral motility, the direct evidence also shows that about 20% of PEDVs can undergo an abortive entry via CME and CavME. Additionally, the dynamic trafficking of PEDV from clathrin and caveolae structures to early endosomes, and from early endosomes to late endosomes, and viral fusion were directly dissected, and PEDV fusion mainly occurred in late endosomes within ∼6.8 min after the transport of PEDV to late endosomes. Collectively, this work systematically unravels the early steps of PEDV infection, which expands our understanding of the mechanism of CoV infection.IMPORTANCE Emerging and re-emerging coronaviruses cause serious human and animal epidemics worldwide. For many enveloped viruses, including coronavirus, it is evident that breaking the plasma membrane barrier is a pivotal and complex process, which contains multiple dynamic steps. Although great efforts have been made to understand the mechanisms of coronavirus endocytic pathways, the direct real-time imaging of individual porcine epidemic diarrhea coronavirus (PEDV) internalization has not been achieved yet. In this study, we not only dissected the kinetics of PEDV entry via clathrin-mediated endocytosis and caveolae-mediated endocytosis and the kinetics of endosome trafficking and viral fusion but also found a novel productive coronavirus entry manner in which clathrin and caveolae can cooperatively mediate endocytosis of PEDV. Moreover, we uncovered the existence of PEDV abortive endocytosis. In summary, the productive PEDV entry via the cooperation between clathrin and caveolae structures and the abortive endocytosis of PEDV provide new insights into coronavirus penetrating the plasma membrane barrier.


Assuntos
Cavéolas/metabolismo , Clatrina/metabolismo , Endocitose/fisiologia , Vírus da Diarreia Epidêmica Suína/metabolismo , Internalização do Vírus , Animais , Linhagem Celular , Membrana Celular/virologia , Chlorocebus aethiops , Infecções por Coronavirus , Suínos , Doenças dos Suínos/virologia , Células Vero
19.
Nat Commun ; 12(1): 1901, 2021 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-33772008

RESUMO

The trans-Golgi network (TGN) has been known as a key platform to sort and transport proteins to their final destinations in post-Golgi membrane trafficking. However, how the TGN sorts proteins with different destinies still remains elusive. Here, we examined 3D localization and 4D dynamics of TGN-localized proteins of Arabidopsis thaliana that are involved in either secretory or vacuolar trafficking from the TGN, by a multicolor high-speed and high-resolution spinning-disk confocal microscopy approach that we developed. We demonstrate that TGN-localized proteins exhibit spatially and temporally distinct distribution. VAMP721 (R-SNARE), AP (adaptor protein complex)-1, and clathrin which are involved in secretory trafficking compose an exclusive subregion, whereas VAMP727 (R-SNARE) and AP-4 involved in vacuolar trafficking compose another subregion on the same TGN. Based on these findings, we propose that the single TGN has at least two subregions, or "zones", responsible for distinct cargo sorting: the secretory-trafficking zone and the vacuolar-trafficking zone.


Assuntos
Arabidopsis/metabolismo , Microscopia Confocal/métodos , Vacúolos/metabolismo , Rede trans-Golgi/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Clatrina/genética , Clatrina/metabolismo , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Microscopia Eletrônica de Transmissão , Plantas Geneticamente Modificadas , Transporte Proteico , Proteínas R-SNARE/genética , Proteínas R-SNARE/metabolismo , Vacúolos/ultraestrutura , Rede trans-Golgi/ultraestrutura
20.
Cancer Res ; 81(8): 2234-2245, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33622696

RESUMO

Targeted imaging and therapy approaches based on novel prostate-specific membrane antigen (PSMA) inhibitors have fundamentally changed the treatment regimen of prostate cancer. However, the exact mechanism of PSMA inhibitor internalization has not yet been studied, and the inhibitors' subcellular fate remains elusive. Here, we investigated the intracellular distribution of peptidomimetic PSMA inhibitors and of PSMA itself by stimulated emission depletion (STED) nanoscopy, applying a novel nonstandard live cell staining protocol. Imaging analysis confirmed PSMA cluster formation at the cell surface of prostate cancer cells and clathrin-dependent endocytosis of PSMA inhibitors. Following the endosomal pathway, PSMA inhibitors accumulated in prostate cancer cells at clinically relevant time points. In contrast with PSMA itself, PSMA inhibitors were found to eventually distribute homogeneously in the cytoplasm, a molecular condition that promises benefits for treatment as cytoplasmic and in particular perinuclear enrichment of the radionuclide carriers may better facilitate the radiation-mediated damage of cancerous cells. This study is the first to reveal the subcellular fate of PSMA/PSMA inhibitor complexes at the nanoscale and aims to inspire the development of new approaches in the field of prostate cancer research, diagnostics, and therapeutics. SIGNIFICANCE: This study uses STED fluorescence microscopy to reveal the subcellular fate of PSMA/PSMA inhibitor complexes near the molecular level, providing insights of great clinical interest and suggestive of advantageous targeted therapies. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/8/2234/F1.large.jpg.


Assuntos
Citoplasma/metabolismo , Glutamato Carboxipeptidase II/antagonistas & inibidores , Terapia de Alvo Molecular/métodos , Neoplasias da Próstata/metabolismo , Animais , Antígenos de Superfície/metabolismo , Membrana Celular/metabolismo , Clatrina/metabolismo , Endocitose , Endossomos/metabolismo , Glutamato Carboxipeptidase II/metabolismo , Xenoenxertos , Humanos , Masculino , Camundongos , Microscopia de Fluorescência/métodos , Nanotecnologia/métodos , Peptidomiméticos/farmacocinética , Peptidomiméticos/uso terapêutico , Neoplasias da Próstata/tratamento farmacológico , Coloração e Rotulagem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...