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1.
Cells Tissues Organs ; 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38964305

RESUMO

The formation of normal bone and bone healing require the cAMP-responsive element binding protein 3-like-1 (Creb3l1) transmembrane transcription factor, as deletion of the murine CREB3L1 results in osteopenic animals with limited capacity to repair bone after fracture. Creb3l1 undergoes regulated intra-membrane proteolysis (RIP) to release the N-terminal transcription activating (TA) fragment that enters the nucleus and regulates the expression of target genes. To expand our understanding of Creb3l1 role in skeletal development and skeletal patterning, we aimed to generate animals expressing only the TA fragment of Creb3l1 lacking the transmembrane domain and thereby not regulated through RIP. However, the CRISPR/Cas9-mediated genome editing in zebrafish D. rerio caused a frame-shift mutation that added 56 random amino acids at the C-terminus of the TA fragment (TA+), making it unable to enter the nucleus. Thus, TA+ doesn't regulate transcription, and the creb3l1TA+/TA+ fish animals are creb3l1 transcriptional nulls. We document that the creb3l1TA+/TA+ fish exhibit defects in the patterning of caudal fin lepidotrichia, with significantly distalized points of proximal bifurcation and decreased secondary bifurcations. Moreover, using the caudal fin amputation model, we show that creb3l1TA+/TA+ fish have decreased capacity for regeneration, and that their regenerates replicate the distalization and bifurcation defects observed in intact fins of creb3l1TA+/TA+ animals. These defects correlate with altered expression of the shha and ptch2 components of the Sonic Hedgehog signaling pathway in creb3l1TA+/TA+ regenerates. Together, our results uncover a previously unknown intersection between Creb3l1 and the Sonic Hedgehog pathway, and document a novel role of Creb3l1 in tissue patterning.

2.
Am J Med Genet A ; 182(7): 1767-1775, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32297715

RESUMO

Autosomal recessive SOPH syndrome was first described in the Yakuts population of Asia by Maksimova et al. in 2010. It arises from biallelic pathogenic variants in the NBAS gene and is characterized by severe postnatal growth retardation, senile facial appearance, small hands and feet, optic atrophy with loss of visual acuity and color vision, and normal intelligence (OMIM #614800). The presence of Pelger-Hüet anomaly in this disorder led to its name as an acronym for Short stature, Optic nerve atrophy, and Pelger-Hüet anomaly. Recent publications have further contributed to the characterization of this syndrome through additional phenotype-genotype correlations. We review the clinical features described in these publications and report on a 27-year-old woman with dwarfism with osteolysis and multiple skeletal problems, minor anomalies, immunodeficiency, diabetes mellitus, and multiple secondary medical problems. Her condition was considered an unknown autosomal recessive disorder for many years until exome sequencing provided the diagnosis by revealing a founder disease-causing variant that was compound heterozygous with a novel pathogenic variant in NBAS. Based on the major clinical features of this individual and others reported earlier, a revision of the acronym is warranted to facilitate clinical recognition.


Assuntos
Nanismo/genética , Síndromes de Imunodeficiência/genética , Proteínas de Neoplasias/genética , Anomalia de Pelger-Huët/genética , Adulto , Nanismo/complicações , Nanismo/patologia , Feminino , Predisposição Genética para Doença , Humanos , Síndromes de Imunodeficiência/complicações , Síndromes de Imunodeficiência/patologia , Mutação/genética , Atrofia Óptica/genética , Atrofia Óptica/patologia , Anomalia de Pelger-Huët/complicações , Anomalia de Pelger-Huët/patologia , Sequenciamento do Exoma
3.
J Cell Sci ; 130(24): 4155-4167, 2017 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-29093023

RESUMO

Many secretory cells increase the synthesis and secretion of cargo proteins in response to specific stimuli. How cells couple increased cargo load with a coordinate rise in secretory capacity to ensure efficient transport is not well understood. We used thyroid cells stimulated with thyrotropin (TSH) to demonstrate a coordinate increase in the production of thyroid-specific cargo proteins and ER-Golgi transport factors, and a parallel expansion of the Golgi complex. TSH also increased expression of the CREB3L1 transcription factor, which alone caused amplified transport factor levels and Golgi enlargement. Furthermore, CREB3L1 potentiated the TSH-induced increase in Golgi volume. A dominant-negative CREB3L1 construct hampered the ability of TSH to induce Golgi expansion, implying that this transcription factor contributes to Golgi expansion. Our findings support a model in which CREB3L1 acts as a downstream effector of TSH to regulate the expression of cargo proteins, and simultaneously increases the synthesis of transport factors and the expansion of the Golgi to synchronize the rise in cargo load with the amplified capacity of the secretory pathway.


Assuntos
Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Complexo de Golgi/genética , Proteínas do Tecido Nervoso/genética , Glândula Tireoide/metabolismo , Tireotropina/genética , Linhagem Celular , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Retículo Endoplasmático/genética , Retículo Endoplasmático/metabolismo , Regulação da Expressão Gênica/genética , Complexo de Golgi/metabolismo , Humanos , Proteínas do Tecido Nervoso/metabolismo , Via Secretória/genética , Tireotropina/metabolismo
4.
Traffic ; 16(9): 962-77, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26031340

RESUMO

Dengue viruses cause the most important human viral disease transmitted by mosquitoes. In recent years, a great deal has been learned about molecular details of dengue virus genome replication; however, little is known about genome encapsidation and the functions of the viral capsid protein. During infection, dengue virus capsid progressively accumulates around lipid droplets (LDs) by an unknown mechanism. Here, we examined the process by which the viral capsid is transported from the endoplasmic reticulum (ER) membrane, where the protein is synthesized, to LDs. Using different methods of intervention, we found that the GBF1-Arf1/Arf4-COPI pathway is necessary for capsid transport to LDs, while the process is independent of both COPII components and Golgi integrity. The transport was sensitive to Brefeldin A, while a drug resistant form of GBF1 was sufficient to restore capsid subcellular distribution in infected cells. The mechanism by which LDs gain or lose proteins is still an open question. Our results support a model in which the virus uses a non-canonical function of the COPI system for capsid accumulation on LDs, providing new ideas for antiviral strategies.


Assuntos
Fator 1 de Ribosilação do ADP/metabolismo , Proteínas do Capsídeo/metabolismo , Complexo I de Proteína do Envoltório/metabolismo , Vírus da Dengue/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Gotículas Lipídicas/metabolismo , Linhagem Celular Tumoral , Vírus da Dengue/patogenicidade , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/virologia , Humanos , Gotículas Lipídicas/virologia , Transporte Proteico
5.
J Cell Sci ; 125(Pt 8): 1896-909, 2012 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-22328511

RESUMO

The tethering factor p115 (known as Uso1p in yeast) has been shown to facilitate Golgi biogenesis and membrane traffic in cells in culture. However, the role of p115 within an intact animal is largely unknown. Here, we document that depletion of p115 by using RNA interference (RNAi) in C. elegans causes accumulation of the 170 kD soluble yolk protein (YP170) in the body cavity and retention of the yolk receptor RME-2 in the ER and the Golgi within oocytes. Structure-function analyses of p115 have identified two homology regions (H1 and H2) within the N-terminal globular head and the coiled-coil 1 (CC1) domain as essential for p115 function. We identify a new C-terminal domain of p115 as necessary for Golgi ribbon formation and cargo trafficking. We show that p115 mutants that lack the fourth CC domain (CC4) act in a dominant-negative manner to disrupt Golgi and prevent cargo trafficking in cells containing endogenous p115. Furthermore, using RNAi of p115 and the subsequent transfection with p115 deletion mutants, we show that CC4 is necessary for Golgi ribbon formation and membrane trafficking in cells depleted of endogenous p115. p115 has been shown to bind a subset of ER-Golgi SNAREs through CC1 and CC4 domains (Shorter et al., 2002). Our findings show that CC4 is required for p115 function, and suggest that both the CC1 and the CC4 SNARE-binding motifs participate in p115-mediated membrane tethering.


Assuntos
Caenorhabditis elegans/metabolismo , Membrana Celular/metabolismo , Complexo de Golgi/metabolismo , Proteínas de Transporte Vesicular/química , Proteínas de Transporte Vesicular/metabolismo , Animais , Caenorhabditis elegans/química , Caenorhabditis elegans/genética , Membrana Celular/genética , Complexo de Golgi/química , Complexo de Golgi/genética , Proteínas da Matriz do Complexo de Golgi , Estrutura Terciária de Proteína , Transporte Proteico , Proteínas de Transporte Vesicular/genética
6.
Bioinformatics ; 28(18): 2394-6, 2012 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-22815362

RESUMO

SUMMARY: The application of docking to large-scale experiments or the explicit treatment of protein flexibility are part of the new challenges in structural bioinformatics that will require large computer resources and more efficient algorithms. Highly optimized fast Fourier transform (FFT) approaches are broadly used in docking programs but their optimal code implementation leaves hardware acceleration as the only option to significantly reduce the computational cost of these tools. In this work we present Cell-Dock, an FFT-based docking algorithm adapted to the Cell BE processor. We show that Cell-Dock runs faster than FTDock with maximum speedups of above 200×, while achieving results of similar quality. AVAILABILITY AND IMPLEMENTATION: The source code is released under GNU General Public License version 2 and can be downloaded from http://mmb.pcb.ub.es/~cpons/Cell-Dock. CONTACT: djimenez@ac.upc.edu or juanf@bsc.es SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Algoritmos , Simulação de Acoplamento Molecular/métodos , Complexos Multiproteicos/química , Análise de Fourier , Software
7.
Traffic ; 11(9): 1246-61, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20545908

RESUMO

Autophagy is an important cellular degradation pathway present in all eukaryotic cells. Via this pathway, portions of the cytoplasm and/or organelles are sequestered in double-membrane structures called autophagosomes. In spite of the significant advance achieved in autophagy, the long-standing question about the source of the autophagic membrane remains unsolved. We have investigated the role of the secretory pathway in autophagosome biogenesis. Sar1 and Rab1b are monomeric GTPases that control traffic from the endoplasmic reticulum (ER) to the Golgi. We present evidence indicating that the activity of both proteins is required for autophagosome formation. Overexpression of dominant-negative mutants and the use of siRNAs impaired autophagosome generation as determined by LC3 puncta formation and light chain 3 (LC3)-II processing. In addition, our results indicate that the autophagic and secretory pathways intersect at a level preceding the brefeldin A blockage, suggesting that the transport from the cis/medial Golgi is not necessary for autophagosome biogenesis. Our present results highlight the role of transport from the ER in the initial events of the autophagic vacuole development.


Assuntos
Autofagia , Retículo Endoplasmático/metabolismo , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Fagossomos/enzimologia , Proteínas rab1 de Ligação ao GTP/metabolismo , Animais , Células CHO , Cricetinae , Cricetulus , Técnicas de Silenciamento de Genes , Proteínas Monoméricas de Ligação ao GTP/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Via Secretória , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismo
8.
Cells ; 11(8)2022 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-35455992

RESUMO

The transcription factor CREB3L1 is expressed in a wide variety of tissues including cartilage, pancreas, and bone. It is located in the endoplasmic reticulum and upon stimulation is transported to the Golgi where is proteolytically cleaved. Then, the N-terminal domain translocates to the nucleus to activate gene expression. In thyroid follicular cells, CREB3L1 is a downstream effector of thyrotropin (TSH), promoting the expression of proteins of the secretory pathway along with an expansion of the Golgi volume. Here, we analyzed the role of CREB3L1 as a TSH-dependent transcriptional regulator of the expression of the sodium/iodide symporter (NIS), a major thyroid protein that mediates iodide uptake. We show that overexpression and inhibition of CREB3L1 induce an increase and decrease in the NIS protein and mRNA levels, respectively. This, in turn, impacts on NIS-mediated iodide uptake. Furthermore, CREB3L1 knockdown hampers the increase the TSH-induced NIS expression levels. Finally, the ability of CREB3L1 to regulate the promoter activity of the NIS-coding gene (Slc5a5) was confirmed. Taken together, our findings highlight the role of CREB3L1 in maintaining the homeostasis of thyroid follicular cells, regulating the adaptation of the secretory pathway as well as the synthesis of thyroid-specific proteins in response to TSH stimulation.


Assuntos
Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico , Simportadores , Células Epiteliais da Tireoide , Animais , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Ratos , Simportadores/genética , Simportadores/metabolismo , Células Epiteliais da Tireoide/metabolismo , Tireotropina/metabolismo , Tireotropina/farmacologia
9.
Nat Commun ; 13(1): 2072, 2022 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-35440597

RESUMO

Peripheral membrane proteins (PMPs) associate with cellular membranes through post-translational modifications like S-palmitoylation. The Golgi apparatus is generally viewed as the transitory station where palmitoyl acyltransferases (PATs) modify PMPs, which are then transported to their ultimate destinations such as the plasma membrane (PM). However, little substrate specificity among the many PATs has been determined. Here we describe the inherent partitioning of Gαo - α-subunit of heterotrimeric Go proteins - to PM and Golgi, independent from Golgi-to-PM transport. A minimal code within Gαo N-terminus governs its compartmentalization and re-coding produces G protein versions with shifted localization. We establish the S-palmitoylation at the outer nuclear membrane assay ("SwissKASH") to probe substrate specificity of PATs in intact cells. With this assay, we show that PATs localizing to different membrane compartments display remarkable substrate selectivity, which is the basis for PMP compartmentalization. Our findings uncover a mechanism governing protein localization and establish the basis for innovative drug discovery.


Assuntos
Aciltransferases , Lipoilação , Aciltransferases/metabolismo , Membrana Celular/metabolismo , Complexo de Golgi/metabolismo , Transporte Proteico
10.
Geriatr Nurs ; 32(1): 39-45, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21146901

RESUMO

Physical restraint use among hospitalized older adults remains an important issue. Despite evidence indicating that restraints can be harmful and strict regulatory rules restricting the use of restraints, healthcare practitioners continue to utilize physical restraints, often in the name of safety. The purpose of this study was to examine the perceptions regarding physical restraint use among registered nurses (RNs) and nursing assistants (NAs). The Perceptions of Restraint Use Questionnaire (PRUQ) was used to evaluate nursing staff perceptions. The overall mean score for the PRUQ was 2.8 out of a possible 5, indicating a neutral perception. Both RNs and NAs identified treatment interference as the most important reason for restraining a patient and substituting of restraints for staff as the least important reason. This study revealed an overall less favorable perception of restraints than previous studies. NAs favored physical restraint for fall prevention more than RNs. It was also noted that protection from physical abuse and patient combativeness was the most salient reason cited by the emergency department staff.


Assuntos
Enfermeiros Clínicos/psicologia , Assistentes de Enfermagem/psicologia , Recursos Humanos de Enfermagem Hospitalar/psicologia , Restrição Física , Idoso , Idoso de 80 Anos ou mais , Atitude do Pessoal de Saúde , Serviço Hospitalar de Emergência , Avaliação de Desempenho Profissional , Feminino , Humanos , Unidades de Terapia Intensiva , Masculino , Percepção , Estudos de Amostragem , Inquéritos e Questionários
11.
Front Mol Neurosci ; 14: 650338, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34421533

RESUMO

Nerve growth factor (NGF) stimulates numerous cellular physiological processes, including growth, differentiation, and survival, and maintains the phenotype of several neuronal types. Most of these NGF-induced processes require adaptation of the secretory pathway since they involve extensive remodeling of membranes and protein redistribution along newly formed neuritic processes. CREB3 transcription factors have emerged as signaling hubs for the regulation of numerous genes involved in the secretory pathway and Golgi homeostasis, integrating stimuli from multiple sources to control secretion, posttranslational modifications and trafficking of proteins. Although recent studies have focused on their role in the central nervous system, little is known about their participation in cell differentiation. Therefore, we aimed to analyze the expression and signaling mechanism of CREB3 transcription factor family members, using the NGF-induced PC12 cell differentiation model. Results show that NGF treatment causes Golgi enlargement and a parallel increased expression of proteins and mRNAs encoding for proteins required for membrane transport (transport factors). Additionally, a significant increase in CREB3L2 protein and mRNA levels is detected in response to NGF. Both MAPK and cAMP signaling pathways are required for this response. Interestingly, CREB3L2 overexpression hampers the NGF-induced neurite outgrowth while its inhibition enhances the morphological changes driven by NGF. In agreement, CREB3L2 overexpressing cells display higher immunofluorescence intensity of Rab5 GTPase (a negative regulator of PC12 differentiation) than control cells. Also, Rab5 immunofluorescence levels decrease in CREB3L2-depleted cells. Taken together, our findings imply that CREB3L2 is an important downstream effector of NGF-activated pathways, leading to neuronal differentiation.

12.
Mol Biol Cell ; 18(7): 2400-10, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17429068

RESUMO

Assembly of the cytosolic coat protein I (COPI) complex at the ER-Golgi interface is directed by the ADP ribosylation factor1 (Arf1) and its guanine nucleotide exchange factor (GBF1). Rab1b GTPase modulates COPI recruitment, but the molecular mechanism underlying this action remains unclear. Our data reveal that in vivo expression of the GTP-restricted Rab1b mutant (Rab1Q67L) increased the association of GBF1 and COPI to peripheral structures localized at the ER exit sites (ERES) interface. Active Rab1b also stabilized Arf1 on Golgi membranes. Furthermore, we characterized GBF1 as a new Rab1b effector, and showed that its N-terminal domain was involved in this interaction. Rab1b small interfering RNA oligonucleotide assays suggested that Rab1b was required for GBF1 membrane association. To further understand how Rab1b functions in ER-to-Golgi transport, we analyzed GFP-Rab1b dynamics in HeLa cells. Time-lapse microscopy indicated that the majority of the Rab1b-labeled punctuated structures are relatively short-lived with limited-range movements. FRAP of Golgi GFP-Rab1bwt showed rapid recovery (t(1/2) 120 s) with minimal dependence on microtubules. Our data support a model where Rab1b-GTP induces GBF1 recruitment at the ERES interface and at the Golgi complex where it is required for COPII/COPI exchange or COPI vesicle formation, respectively.


Assuntos
Fator 1 de Ribosilação do ADP/metabolismo , Complexo I de Proteína do Envoltório/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Proteínas rab1 de Ligação ao GTP/metabolismo , Membrana Celular/metabolismo , Retículo Endoplasmático/metabolismo , Imunofluorescência , Fatores de Troca do Nucleotídeo Guanina/química , Células HeLa , Humanos , Cinética , Proteínas Mutantes/metabolismo , Ligação Proteica , Transporte Proteico
13.
Mol Biol Cell ; 17(7): 2996-3008, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16624868

RESUMO

The mechanisms regulating membrane recruitment of the p115 tethering factor in vivo are unknown. Here, we describe cycling of p115 between membranes and cytosol and document the effects of Golgi matrix proteins, Rab1, and soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (SNAP) receptors (SNAREs) on this process. Rapid membrane/cytosol exchange is shown by swift (t1/2 approximately 20 s) loss of Golgi-localized p115-green fluorescent protein (GFP) after repeated photobleaching of cell periphery and rapid (t1/2 approximately 13 s) fluorescence recovery after photobleaching Golgi-localized p115-GFP. p115 mutant missing the GM130/giantin binding site exhibits analogous fluorescence recovery after photobleaching (FRAP) (t1/2 approximately 13 s), suggesting that GM130 and giantin are not major determinants of p115 membrane dynamics. In contrast, p115-GFP exchanges more rapidly (t1/2 approximately 8 s) in cells expressing the inactive Rab1/N121I mutant, indicating that p115 cycling is influenced by Rab1. p115-GFP dynamics is also influenced by the assembly status of SNAREs. In cells expressing an ATPase-deficient NSF/E329Q mutant that inhibits SNARE complex disassembly, the cycling kinetics of p115-GFP are significantly slower (t1/2 approximately 21 s). In contrast, in cells incubated at reduced temperature (10 degrees C) that inhibits vesicular traffic, the cycling kinetics of p115-GFP are faster (t1/2 approximately 7 s). These data suggest that p115-binding sites on the membrane are provided by unassembled SNAREs. In agreement, biochemical studies show increased p115 recruitment to membranes in the presence of NSF and alpha-SNAP. Our data support a model in which recruitment of tethers is directly regulated by the assembly status of SNAREs.


Assuntos
Retículo Endoplasmático/metabolismo , Complexo de Golgi/metabolismo , Membranas Intracelulares/metabolismo , Proteínas de Membrana/metabolismo , Proteínas SNARE/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Animais , Autoantígenos , Citosol/química , Citosol/metabolismo , Retículo Endoplasmático/química , Proteínas da Matriz do Complexo de Golgi , Proteínas de Fluorescência Verde/análise , Proteínas de Fluorescência Verde/genética , Humanos , Membranas Intracelulares/química , Cinética , Proteínas de Membrana/análise , Proteínas de Membrana/genética , Proteínas Sensíveis a N-Etilmaleimida/metabolismo , Transporte Proteico , Ratos , Proteínas de Transporte Vesicular/análise , Proteínas de Transporte Vesicular/genética , Proteínas rab1 de Ligação ao GTP/genética , Proteínas rab1 de Ligação ao GTP/metabolismo
14.
Front Cell Dev Biol ; 7: 123, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31334233

RESUMO

CREB3 family of transcription factors are ER localized proteins that belong to the bZIP family. They are transported from the ER to the Golgi, cleaved by S1P and S2P proteases and the released N-terminal domains act as transcription factors. CREB3 family members regulate the expression of a large variety of genes and according to their tissue-specific expression profiles they play, among others, roles in acute phase response, lipid metabolism, development, survival, differentiation, organelle autoregulation, and protein secretion. They have been implicated in the ER and Golgi stress responses as regulators of the cell secretory capacity and cell specific cargos. In this review we provide an overview of the diverse functions of each member of the family (CREB3, CREB3L1, CREB3L2, CREB3L3, CREB3L4) with special focus on their role in the central nervous system.

15.
Mol Biol Cell ; 14(5): 2116-27, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12802079

RESUMO

The small GTPase Rab1b is essential for endoplasmic reticulum (ER) to Golgi transport, but its exact function remains unclear. We have examined the effects of wild-type and three mutant forms of Rab1b in vivo. We show that the inactive form of Rab1b (the N121I mutant with impaired guanine nucleotide binding) blocks forward transport of cargo and induces Golgi disruption. The phenotype is analogous to that induced by brefeldin A (BFA): it causes resident Golgi proteins to relocate to the ER and induces redistribution of ER-Golgi intermediate compartment proteins to punctate structures. The COPII exit machinery seems to be functional in cells expressing the N121I mutant, but COPI is compromised, as shown by the release of beta-COP into the cytosol. Our results suggest that Rab1b function influences COPI recruitment. In support of this, we show that the disruptive effects of N121I can be reversed by expressing known mediators of COPI recruitment, the GTPase ARF1 and its guanine nucleotide exchange factor GBF1. Further evidence is provided by the finding that cells expressing the active form of Rab1b (the Q67L mutant with impaired GTPase activity) are resistant to BFA. Our data suggest a novel role for Rab1b in ARF1- and GBF1-mediated COPI recruitment pathway.


Assuntos
Complexo I de Proteína do Envoltório/metabolismo , Proteínas rab1 de Ligação ao GTP/metabolismo , Fator 1 de Ribosilação do ADP/genética , Fator 1 de Ribosilação do ADP/metabolismo , Transporte Biológico Ativo/fisiologia , Complexo I de Proteína do Envoltório/genética , Técnicas de Transferência de Genes , Complexo de Golgi/metabolismo , Fatores de Troca do Nucleotídeo Guanina/genética , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Células HeLa , Humanos , Mutação , Proteínas rab1 de Ligação ao GTP/genética
16.
Mol Biol Cell ; 14(6): 2250-61, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12808027

RESUMO

ADP-ribosylation factor (ARF) mediated recruitment of COPI to membranes plays a central role in transport between the endoplasmic reticulum (ER) and the Golgi. The activation of ARFs is mediated by guanine nucleotide exchange factors (GEFs). Although several ARF-GEFs have been identified, the transport steps in which they function are still poorly understood. Here we report that GBF1, a member of the Sec7-domain family of GEFs, is responsible for the regulation of COPI-mediated events at the ER-Golgi interface. We show that GBF1 is essential for the formation, differentiation, and translocation of pre-Golgi intermediates and for the maintenance of Golgi integrity. We also show that the formation of transport-competent ER-to-Golgi intermediates proceeds in two stages: first, a COPI-independent event leads to the formation of an unstable compartment, which is rapidly reabsorbed in the absence of GBF1 activity. Second, the association of GBF1 with this compartment allows COPI recruitment and leads to its maturation into transport intermediates. The recruitment of GBF1 to this compartment is specifically inhibited by brefeldin A. Our findings imply that the continuous recruitment of GBF1 to spatially differentiated membrane domains is required for sustained membrane remodeling that underlies membrane traffic and Golgi biogenesis.


Assuntos
Fatores de Ribosilação do ADP/metabolismo , Complexo I de Proteína do Envoltório/metabolismo , Retículo Endoplasmático/metabolismo , Complexo de Golgi/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Genes Reporter , Fatores de Troca do Nucleotídeo Guanina/genética , Humanos
17.
Neumol. pediátr. (En línea) ; 17(4): 129-133, 2022. ilus, tab
Artigo em Espanhol | LILACS | ID: biblio-1427371

RESUMO

La displasia broncopulmonar (DBP) es la enfermedad crónica más frecuente del recién nacido prematuro. Los avances en su prevención y tratamiento han permitido una mayor sobrevida de prematuros más pequeños, pero su incidencia se ha mantenido estable en el tiempo, con una fisiopatología y presentación clínica que abarca un amplio espectro y que difiere de la DBP descrita originalmente hace más de 50 años. Aún existen controversias en su definición, la que se ha establecido en base al tratamiento, específicamente al requerimiento de soporte respiratorio. Las definiciones más utilizadas son el requerimiento de oxígeno por 28 días y a las 36 semanas de edad gestacional corregida (EGC). Recientemente se ha propuesto definirla en base al requerimiento de ventilación mecánica a las 36 semanas de EGC, lo que identificaría a los prematuros con DBP más grave y mayor probabilidad de complicaciones respiratorias y neurológicas en los 2 primeros años de vida. Nuestro objetivo en la comisión de Neo-SOCHINEP es el de recomendar la definición y clasificación que nos parece más adecuada para identificar a los prematuros portadores de DBP, considerando los aspectos fisiopatológicos, del compromiso de la función pulmonar y consecuencias prácticas de la definición en nuestro medio. También proponemos la definición del requerimiento de oxígeno en el prematuro cuando esta en neonatología, las condiciones e interpretación de la saturometría contínua cuando está pronto al alta y el seguimiento de la oxigenoterapia posterior al alta.


Bronchopulmonary dysplasia (BPD) is the most frequent chronic disease of the premature newborn. Advances in its prevention and treatment have allowed a greater survival of smaller preterm infants, but its incidence has remained stable over time, with a pathophysiology and clinical presentation that covers a wide spectrum and differs from the BPD originally described more than 50 years ago. There are still controversies in its definition, which has been established based on the treatment, specifically the requirement of respiratory support. The most used definitions are the oxygen requirement for 28 days and at 36 weeks of postmenstrual age (PMA). It has recently been proposed a definition based on the requirement of mechanical ventilation at 36 weeks of PMA, which would identify premature infants with more severe BPD and a greater probability of respiratory and neurological complications in the first 2 years of life. Our objective in the Neo-SOCHINEP commission is to recommend the definition and classification that we believe is most appropriate to identify premature infants with BPD, considering the pathophysiological aspects, the compromised lung function, and practical consequences of the definition in our medium. We also propose the definition of the oxygen requirement in premature infants when they are in neonatology, the conditions and interpretation of continuous saturation when they are soon discharged, and the follow-up of post-discharge oxygen therapy.


Assuntos
Humanos , Recém-Nascido , Displasia Broncopulmonar/diagnóstico , Displasia Broncopulmonar/fisiopatologia , Doenças do Prematuro , Recém-Nascido Prematuro
18.
PLoS One ; 11(8): e0160838, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27500526

RESUMO

The GTPase Rab1b is involved in ER to Golgi transport, with multiple Rab1b effectors (located at ERES, VTCs and the Golgi complex) being required for its function. In this study, we performed live-cell dual-expression studies to analyze the dynamics of Rab1b and some effectors located at the ERES-Golgi interface. Rab1b occupied widely distributed mobile punctate and tubular structures, displaying a transient overlaps with its effectors and showing that these overlaps occurred at the same time in spatially distinct steps of ER to Golgi transport. In addition, we assessed Rab1b dynamics during cargo sorting by analyzing the concentration at ERES of a Golgi protein (SialT2-CFP) during Brefeldin A washout (BFA WO). Rab1b was associated to most of the ERES structures, but at different times during BFA WO, and recurrently SialT2-CFP was sorted in the ERES-Rab1b positive structures. Furthermore, we reveal for first time that Rab1b localization time at ERES depended on GBF1, a Rab1b effector that acts as the guanine nucleotide exchange factor of Arf1, and that Rab1b membrane association/dissociation dynamics at ERES was dependent on the GBF1 membrane association and activity, which strongly suggests that GBF1 activity modulates Rab1b membrane cycling dynamic.


Assuntos
Retículo Endoplasmático/metabolismo , Complexo de Golgi/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Proteínas rab1 de Ligação ao GTP/metabolismo , Brefeldina A/farmacologia , Retículo Endoplasmático/efeitos dos fármacos , Complexo de Golgi/efeitos dos fármacos , Células HeLa , Humanos , Inibidores da Síntese de Proteínas/farmacologia , Transporte Proteico
19.
Rev. cuba. pediatr ; 92(supl.1): e1128, 2020. tab
Artigo em Espanhol | LILACS, CUMED | ID: biblio-1156609

RESUMO

En diciembre de 2019 se reporta un brote de infección respiratoria aguda de etiología desconocida, en la ciudad de Wuhan, China, cuya causa se atribuyó poco después a un nuevo virus denominado SARS-CoV-2. En marzo de 2020 la enfermedad causada por este virus: COVID-19, fue declarada pandemia por la OMS. Como consecuencia, se recomendó restringir las intervenciones quirúrgicas, limitándolas a aquellas urgentes y las que no debían diferirse por comprometer la salud del paciente. Organismos internacionales y sociedades científicas han emitido recomendaciones para la asistencia sanitaria y la actividad quirúrgica. Se requeriría adecuarlas al contexto social y geográfico donde se desarrollará la actividad de salud en Cuba. Atendiendo a estas circunstancias se elaboraron recomendaciones adaptadas a las condiciones propias de las instituciones hospitalarias de perfil pediátrico más comunes de nuestro país, con el objetivo de contribuir a organizar la asistencia médico quirúrgica de urgencia a pacientes pediátricos positivos o sospechosos de tener COVID-19, cumpliendo las condiciones de seguridad para el paciente y el personal sanitario a su cargo(AU)


In December 2019, it was reported the outbreak of an acute respiratory infection of unknown etiology, in the city of Wuhan, China, whose cause was shortly after attributed to a new virus called SARS-CoV-2. In March 2020 the disease caused by this virus, COVID-19, was declared a pandemic by the WHO. As a consequence, it was recommended to restrict surgical interventions, limiting them to those that are priorities and the ones that should not be deferred since can be compromised the health of the patient. International agencies and scientific societies have issued recommendations for the health care and surgical activities. It is needed to suit them to the social and geographical context where the health activity is developed in Cuba. This is the reason to conform recommendations adapted to the conditions of pediatric medical institutions in our country, with the aim of contributing to organize the emergency surgical care to pediatric patients positive or suspected of having COVID-19, while accomplishing the safety requirements for the patient and the health personnel in charge(AU)


Assuntos
Humanos , Procedimentos Cirúrgicos Operatórios , Organização Mundial da Saúde , Agências Internacionais , Infecções por Coronavirus , Emergências , Betacoronavirus
20.
Rev. argent. reumatolg. (En línea) ; 31(3): 32-35, set. 2020. ilus
Artigo em Espanhol | LILACS, BINACIS | ID: biblio-1149673

RESUMO

La artritis séptica poliarticular se define como la infección de dos o más articulaciones, casi siempre de etiología bacteriana y diseminación hematógena. Es considerada una emergencia médica, lo que conlleva reconocerla precozmente, evitar la diseminación de la infección asociada con alta mortalidad y el riesgo de daño estructural articular. Presentamos tres casos de artritis séptica poliarticular, destacándose la importancia de la sospecha clínica y el estudio temprano del líquido sinovial para el diagnóstico y el tratamiento con antimicrobianos, evacuación y lavado articular.


Polyarticular septic arthritis is defined as the infection of two or more joints, almost always of bacterial etiology and hematogenous spread. It is considered a medical emergency, which should be recognized early, avoiding the spread of infection, associated with high mortality and the risk of joint structural damage. We present three cases of polyarticular septic arthritis, highlighting the importance of clinical suspicion and early synovial fluid study for diagnosis and treatment with antimicrobials, joint evacuation and joint lavage.


Assuntos
Humanos , Masculino , Artrite Reumatoide , Artrite , Líquido Sinovial , Terapêutica , Artrite Infecciosa
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