Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 42
Filtrar
Más filtros













Base de datos
Intervalo de año de publicación
1.
Adv Sci (Weinh) ; 11(15): e2306027, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38353396

RESUMEN

Temozolomide (TMZ) represents the cornerstone of therapy for glioblastoma (GBM). However, acquisition of resistance limits its therapeutic potential. The human kinome is an undisputable source of druggable targets, still, current knowledge remains confined to a limited fraction of it, with a multitude of under-investigated proteins yet to be characterized. Here, following a kinome-wide RNAi screen, pantothenate kinase 4 (PANK4) isuncovered as a modulator of TMZ resistance in GBM. Validation of PANK4 across various TMZ-resistant GBM cell models, patient-derived GBM cell lines, tissue samples, as well as in vivo studies, corroborates the potential translational significance of these findings. Moreover, PANK4 expression is induced during TMZ treatment, and its expression is associated with a worse clinical outcome. Furthermore, a Tandem Mass Tag (TMT)-based quantitative proteomic approach, reveals that PANK4 abrogation leads to a significant downregulation of a host of proteins with central roles in cellular detoxification and cellular response to oxidative stress. More specifically, as cells undergo genotoxic stress during TMZ exposure, PANK4 depletion represents a crucial event that can lead to accumulation of intracellular reactive oxygen species (ROS) and subsequent cell death. Collectively, a previously unreported role for PANK4 in mediating therapeutic resistance to TMZ in GBM is unveiled.


Asunto(s)
Neoplasias Encefálicas , Glioblastoma , Humanos , Temozolomida/farmacología , Temozolomida/uso terapéutico , Glioblastoma/tratamiento farmacológico , Glioblastoma/metabolismo , Proteómica , Antineoplásicos Alquilantes/farmacología , Antineoplásicos Alquilantes/uso terapéutico , Resistencia a Antineoplásicos , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/metabolismo , Línea Celular Tumoral
2.
Elife ; 122023 08 24.
Artículo en Inglés | MEDLINE | ID: mdl-37615341

RESUMEN

Arrested replication forks, when restarted by homologous recombination, result in error-prone DNA syntheses and non-allelic homologous recombination. Fission yeast RTS1 is a model fork barrier used to probe mechanisms of recombination-dependent restart. RTS1 barrier activity is entirely dependent on the DNA binding protein Rtf1 and partially dependent on a second protein, Rtf2. Human RTF2 was recently implicated in fork restart, leading us to examine fission yeast Rtf2's role in more detail. In agreement with previous studies, we observe reduced barrier activity upon rtf2 deletion. However, we identified Rtf2 to be physically associated with mRNA processing and splicing factors and rtf2 deletion to cause increased intron retention. One of the most affected introns resided in the rtf1 transcript. Using an intronless rtf1, we observed no reduction in RFB activity in the absence of Rtf2. Thus, Rtf2 is essential for correct rtf1 splicing to allow optimal RTS1 barrier activity.


Asunto(s)
Schizosaccharomyces , Humanos , Schizosaccharomyces/genética , Empalme del ARN , Procesamiento Postranscripcional del ARN , Intrones , Replicación del ADN/genética
3.
FASEB J ; 36(11): e22593, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36251357

RESUMEN

In eukaryotes, CREB-binding protein (CBP), a coactivator of CREB, functions both as a platform for recruiting other components of the transcriptional machinery and as a histone acetyltransferase (HAT) that alters chromatin structure. We previously showed that the transcriptional activity of cAMP-responsive element binding protein (CREB) plays a crucial role in neuronal plasticity in the pond snail Lymnaea stagnalis. However, there is no information on the molecular structure and HAT activity of CBP in the Lymnaea central nervous system (CNS), hindering an investigation of its postulated role in long-term memory (LTM). Here, we characterize the Lymnaea CBP (LymCBP) gene and identify a conserved domain of LymCBP as a functional HAT. Like CBPs of other species, LymCBP possesses functional domains, such as the KIX domain, which is essential for interaction with CREB and was shown to regulate LTM. In-situ hybridization showed that the staining patterns of LymCBP mRNA in CNS are very similar to those of Lymnaea CREB1. A particularly strong LymCBP mRNA signal was observed in the cerebral giant cell (CGC), an identified extrinsic modulatory interneuron of the feeding circuit, the key to both appetitive and aversive LTM for taste. Biochemical experiments using the recombinant protein of the LymCBP HAT domain showed that its enzymatic activity was blocked by classical HAT inhibitors. Preincubation of the CNS with such inhibitors blocked cAMP-induced synaptic facilitation between the CGC and an identified follower motoneuron of the feeding system. Taken together, our findings suggest a role for the HAT activity of LymCBP in synaptic plasticity in the feeding circuitry.


Asunto(s)
Proteína de Unión a CREB , Lymnaea , Animales , Proteína de Unión a CREB/genética , Proteína de Unión a CREB/metabolismo , Sistema Nervioso Central/metabolismo , Cromatina/metabolismo , Lymnaea/genética , Lymnaea/metabolismo , ARN Mensajero/metabolismo , Proteínas Recombinantes/metabolismo
4.
J Exp Biol ; 225(7)2022 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-35403696

RESUMEN

Applications of key technologies in biomedical research, such as qRT-PCR or LC-MS-based proteomics, are generating large biological (-omics) datasets which are useful for the identification and quantification of biomarkers in any research area of interest. Genome, transcriptome and proteome databases are already available for a number of model organisms including vertebrates and invertebrates. However, there is insufficient information available for protein sequences of certain invertebrates, such as the great pond snail Lymnaea stagnalis, a model organism that has been used highly successfully in elucidating evolutionarily conserved mechanisms of memory function and dysfunction. Here, we used a bioinformatics approach to designing and benchmarking a comprehensive central nervous system (CNS) proteomics database (LymCNS-PDB) for the identification of proteins from the CNS of Lymnaea by LC-MS-based proteomics. LymCNS-PDB was created by using the Trinity TransDecoder bioinformatics tool to translate amino acid sequences from mRNA transcript assemblies obtained from a published Lymnaea transcriptomics database. The blast-style MMSeq2 software was used to match all translated sequences to UniProtKB sequences for molluscan proteins, including those from Lymnaea and other molluscs. LymCNS-PDB contains 9628 identified matched proteins that were benchmarked by performing LC-MS-based proteomics analysis with proteins isolated from the Lymnaea CNS. MS/MS analysis using the LymCNS-PDB database led to the identification of 3810 proteins. Only 982 proteins were identified by using a non-specific molluscan database. LymCNS-PDB provides a valuable tool that will enable us to perform quantitative proteomics analysis of protein interactomes involved in several CNS functions in Lymnaea, including learning and memory and age-related memory decline.


Asunto(s)
Biología Computacional , Lymnaea , Animales , Benchmarking , Sistema Nervioso Central , Cromatografía Liquida , Lymnaea/genética , Proteínas/metabolismo , Espectrometría de Masas en Tándem
5.
Biomedicines ; 10(1)2022 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-35052804

RESUMEN

Glioblastoma (GB) is an aggressive type of tumour for which therapeutic options and biomarkers are limited. GB diagnosis mostly relies on symptomatic presentation of the tumour and, in turn, brain imaging and invasive biopsy that can delay its diagnosis. Description of easily accessible and effective biomarkers present in biofluids would thus prove invaluable in GB diagnosis. Extracellular vesicles (EVs) derived from both GB and stromal cells are essential to intercellular crosstalk in the tumour bulk, and circulating EVs have been described as a potential reservoir of GB biomarkers. Therefore, EV-based liquid biopsies have been suggested as a promising tool for GB diagnosis and follow up. To identify GB specific proteins, sEVs were isolated from plasma samples of GB patients as well as healthy volunteers using differential ultracentrifugation, and their content was characterised through mass spectrometry. Our data indicate the presence of an inflammatory biomarker signature comprising members of the complement and regulators of inflammation and coagulation including VWF, FCGBP, C3, PROS1, and SERPINA1. Overall, this study is a step forward in the development of a non-invasive liquid biopsy approach for the identification of valuable biomarkers that could significantly improve GB diagnosis and, consequently, patients' prognosis and quality of life.

8.
Front Microbiol ; 11: 544785, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33042055

RESUMEN

Polynucleobacter asymbioticus strain QLW-P1DMWA-1T represents a group of highly successful heterotrophic ultramicrobacteria that is frequently very abundant (up to 70% of total bacterioplankton) in freshwater habitats across all seven continents. This strain was originally isolated from a shallow Alpine pond characterized by rapid changes in water temperature and elevated UV radiation due to its location at an altitude of 1300 m. To elucidate the strain's adjustment to fluctuating environmental conditions, we recorded changes occurring in its transcriptomic and proteomic profiles under contrasting experimental conditions by simulating thermal conditions in winter and summer as well as high UV irradiation. To analyze the potential connection between gene expression and regulation via methyl group modification of the genome, we also analyzed its methylome. The methylation pattern differed between the three treatments, pointing to its potential role in differential gene expression. An adaptive process due to evolutionary pressure in the genus was deduced by calculating the ratios of non-synonymous to synonymous substitution rates for 20 Polynucleobacter spp. genomes obtained from geographically diverse isolates. The results indicate purifying selection.

9.
Mater Sci Eng C Mater Biol Appl ; 117: 111270, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32919634

RESUMEN

With increasing importance of gold nanoparticles (AuNPs) in the medical field, the understanding of their interactions in biological environments is essential. It is known that the exposure to biological fluids of particles in the nanometric range leads to accumulation of proteins on the particle surface proximity, generating the so-called protein corona. This fact can completely change the properties of AuNPs, thus drastically influencing the characteristics and intended purpose of the particles. Therefore, deep insight on the formation and composition of this protein corona is of extreme importance. Between the different factors that can alter the corona formation, our study focuses on the influence of the shape and particle surface charge. In detail, four different shapes of nanometrical scale (spheres, rods, stars and cages) of comparable size were used, all of them stabilized with three different heterofunctionalized poly(ethylene glycol) thiol (R-PEG-SH) linkers (R = OCH3, COOH or NH2) to check the effect of charge as well. After incubation with human serum, abundant proteins were identified via liquid chromatography-electrospray ionization-tandem mass spectroscopy (LC ESI MS/MS) and compared in terms of their relative abundance. On the basis of statistical evaluations, the shape of our AuNPs showed a greater influence than the surface charge. Especially, cage-shaped AuNPs showed a lower amount of total corona proteins. This shape showed differences in the abundances of individual proteins like albumin, vitronectin and members of the complement system. These results indicate that nanocages could present an improved biocompatibility compared with the other shapes due to the high curvature areas and dense ligation on the flat surfaces that could hinder opsonisation and fast removal by the immune system.


Asunto(s)
Nanopartículas del Metal , Corona de Proteínas , Oro , Humanos , Tamaño de la Partícula , Polietilenglicoles , Espectrometría de Masas en Tándem
10.
Biomolecules ; 10(6)2020 05 30.
Artículo en Inglés | MEDLINE | ID: mdl-32486122

RESUMEN

Brucellosis is a zoonotic infection caused by bacteria of the genus Brucella. The species, B. abortus and B. melitensis, major causative agents of human brucellosis, share remarkably similar genomes, but they differ in their natural hosts, phenotype, antigenic, immunogenic, proteomic and metabolomic properties. In the present study, label-free quantitative proteomic analysis was applied to investigate protein expression level differences. Type strains and field strains were each cultured six times, cells were harvested at a midlogarithmic growth phase and proteins were extracted. Following trypsin digestion, the peptides were desalted, separated by reverse-phase nanoLC, ionized using electrospray ionization and transferred into an linear trap quadrapole (LTQ) Orbitrap Velos mass spectrometer to record full scan MS spectra (m/z 300-1700) and tandem mass spectrometry (MS/MS) spectra of the 20 most intense ions. Database matching with the reference proteomes resulted in the identification of 826 proteins. The Cluster of Gene Ontologies of the identified proteins revealed differences in bimolecular transport and protein synthesis mechanisms between these two strains. Among several other proteins, antifreeze proteins, Omp10, superoxide dismutase and 30S ribosomal protein S14 were predicted as potential virulence factors among the proteins differentially expressed. All mass spectrometry data are available via ProteomeXchange with identifier PXD006348.


Asunto(s)
Proteínas Bacterianas/análisis , Brucella abortus/química , Brucella melitensis/química , Proteómica , Especificidad de la Especie
11.
Elife ; 92020 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-32228863

RESUMEN

Mechanoelectrical transduction is a cellular signalling pathway where physical stimuli are converted into electro-chemical signals by mechanically activated ion channels. We describe here the presence of mechanically activated currents in melanoma cells that are dependent on TMEM87a, which we have renamed Elkin1. Heterologous expression of this protein in PIEZO1-deficient cells, that exhibit no baseline mechanosensitivity, is sufficient to reconstitute mechanically activated currents. Melanoma cells lacking functional Elkin1 exhibit defective mechanoelectrical transduction, decreased motility and increased dissociation from organotypic spheroids. By analysing cell adhesion properties, we demonstrate that Elkin1 deletion is associated with increased cell-substrate adhesion and decreased homotypic cell-cell adhesion strength. We therefore conclude that Elkin1 supports a PIEZO1-independent mechanoelectrical transduction pathway and modulates cellular adhesions and regulates melanoma cell migration and cell-cell interactions.


When cells receive signals about their surrounding environment, this initiates a chain of signals which generate a response. Some of these signalling pathways allow cells to sense physical and mechanical forces via a process called mechanotransduction. There are different types of mechanotransduction. In one pathway, mechanical forces open up specialized channels on the cell surface which allow charged particles to move across the membrane and create an electrical current. Mechanoelectrical transduction plays an important role in the spread of cancer: as cancer cells move away from a tumour they use these signalling pathways to find their way between cells and move into other parts of the body. Understanding these pathways could reveal ways to stop cancer from spreading, making it easier to treat. However, it remains unclear which molecules regulate mechanoelectrical transduction in cancer cells. Now, Patkunarajah, Stear et al. have studied whether mechanoelectrical transduction is involved in the migration of skin cancer cells. To study mechanoelectrical transduction, a fine mechanical input was applied to the skin cancer cells whilst measuring the flow of charged molecules moving across the membrane. This experiment revealed that a previously unknown protein named Elkin1 is required to convert mechanical forces into electrical currents. Deleting this newly found protein caused skin cancer cells to move more slowly and dissociate more easily from tumour-like clusters of cells. These findings suggest that Elkin1 is part of a newly identified mechanotransduction pathway that allows cells to sense mechanical forces from their surrounding environment. More work is needed to determine what role Elkin1 plays in mechanoelectrical transduction and whether other proteins are also involved. This could lead to new approaches that prevent cancer cells from dissociating from tumours and spreading to other body parts.


Asunto(s)
Mecanotransducción Celular/fisiología , Melanoma/patología , Proteínas de la Membrana/fisiología , Adhesión Celular , Comunicación Celular , Línea Celular Tumoral , Movimiento Celular , Humanos , Canales Iónicos/fisiología , Esferoides Celulares
12.
PLoS Genet ; 16(3): e1008649, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32163413

RESUMEN

Unicellular organisms have the prevalent challenge to survive under oxidative stress of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2). ROS are present as by-products of photosynthesis and aerobic respiration. These reactive species are even employed by multicellular organisms as potent weapons against microbes. Although bacterial defences against lethal and sub-lethal oxidative stress have been studied in model bacteria, the role of fluctuating H2O2 concentrations remains unexplored. It is known that sub-lethal exposure of Escherichia coli to H2O2 results in enhanced survival upon subsequent exposure. Here we investigate the priming response to H2O2 at physiological concentrations. The basis and the duration of the response (memory) were also determined by time-lapse quantitative proteomics. We found that a low level of H2O2 induced several scavenging enzymes showing a long half-life, subsequently protecting cells from future exposure. We then asked if the phenotypic resistance against H2O2 alters the evolution of resistance against oxygen stress. Experimental evolution of H2O2 resistance revealed faster evolution and higher levels of resistance in primed cells. Several mutations were found to be associated with resistance in evolved populations affecting different loci but, counterintuitively, none of them was directly associated with scavenging systems. Our results have important implications for host colonisation and infections where microbes often encounter reactive oxygen species in gradients.


Asunto(s)
Escherichia coli/efectos de los fármacos , Peróxido de Hidrógeno/farmacología , Estrés Oxidativo/efectos de los fármacos , Resistencia a Medicamentos , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Evolución Molecular , Estrés Oxidativo/fisiología , Especies Reactivas de Oxígeno/metabolismo
13.
Biochem Biophys Res Commun ; 525(2): 378-383, 2020 04 30.
Artículo en Inglés | MEDLINE | ID: mdl-32098674

RESUMEN

The monocationic quaternary surfactant DOTAP has been used for the delivery of nucleic acids and peptides into mammalian cells. This study tested the applicability of DOTAP for the enhancement of adhesion and invasion frequencies of Yersinia (Y.) similis to enable the analysis of the effects of low-pathogenic bacteria on intestinal epithelial cells. Incubation of Y. similis with DOTAP ahead of infection of C2BBe1 intestinal epithelial cells increased invasion and adhesion frequency four- and five-fold, respectively, in plating assays. Proteomic approaches confirmed the increased bacterial load on infected cells: analysis of protein extracts by two-dimensional difference gel electrophoresis (2D-DIGE) revealed higher amounts of bacterial proteins present in the cells infected with DOTAP-treated bacteria. MALDI-TOF mass spectrometry of selected spots from gel-separated protein extracts confirmed the presence of both bacterial and human cell proteins in the samples. Label-free quantitative proteomics analysis identified 1170 human cell proteins and 699 bacterial proteins. Three times more bacterial proteins (279 vs. 93) were detected in C2BBe1 cells infected with DOTAP-treated bacteria compared to infections with untreated bacteria. Infections with DOTAP-treated Y. similis led to a significant upregulation of the stress-inducible ubiquitin-conjugating enzyme UBE2M in C2BBe1 cells. This points towards a stronger impact of the stress and infection responsive transcription factor AP-1 by enhanced bacterial load. DOTAP-treatment of uninfected C2BBe1 cells led to a significant downregulation of the transmembrane trafficking protein TMED10. The application of DOTAP could be helpful for investigating the impact of otherwise low adherent or invasive bacteria on cultivated mammalian cells without utilisation of genetic modifications.


Asunto(s)
Adhesión Bacteriana/efectos de los fármacos , Infecciones Bacterianas/inducido químicamente , Células Epiteliales/microbiología , Ácidos Grasos Monoinsaturados/farmacología , Compuestos de Amonio Cuaternario/farmacología , Yersinia/efectos de los fármacos , Células Cultivadas , Humanos , Intestinos/citología , Intestinos/microbiología , Prueba de Estudio Conceptual , Proteómica , Factor de Transcripción AP-1/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Yersinia/citología
14.
Int J Nanomedicine ; 14: 7861-7878, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31576128

RESUMEN

BACKGROUND AND PURPOSE: Nanogels (NGs) are promising drug delivery tools but are typically limited to hydrophilic drugs. Many potential new drugs are hydrophobic. Our study systematically investigates amphiphilic NGs with varying hydrophobicity, but similar colloidal features to ensure comparability. The amphiphilic NGs used in this experiment consist of a hydrophilic polymer network with randomly distributed hydrophobic groups. For the synthesis we used a new synthetic platform approach. Their amphiphilic character allows the encapsulation of hydrophobic drugs. Importantly, the hydrophilic/hydrophobic balance determines drug loading and biological interactions. In particular, protein adsorption to NG surfaces is dependent on hydrophobicity and critically determines circulation time. Our study investigates how network hydrophobicity influences protein binding, biocompatibility and cellular uptake. METHODS: Biocompatibility of the NGs was examined by WST-1 assay in monocytic-like THP-1 cells. Serum protein corona formation was investigated using dynamic light scattering and two-dimensional gel electrophoresis. Proteins were identified by liquid chromatography-tandem mass spectrometry. In addition, cellular uptake was analyzed via flow cytometry. RESULTS: All NGs were highly biocompatible. The protein binding patterns for the two most hydrophobic NGs were very similar to each other but clearly different from the hydrophilic ones. Overall, protein binding was increased with increasing hydrophobicity, resulting in increased cellular uptake. CONCLUSION: Our study supports the establishment of structure-property relationships and contributes to the accurate balance between maximum loading capacity with low protein binding, optimal biological half-life and good biocompatibility. This is an important step to derive design principles of amphiphilic NGs to be applied as drug delivery vehicles.


Asunto(s)
Materiales Biocompatibles/farmacología , Endocitosis , Geles/química , Interacciones Hidrofóbicas e Hidrofílicas , Nanopartículas/química , Corona de Proteínas/química , Tensoactivos/química , Adsorción , Supervivencia Celular/efectos de los fármacos , Análisis por Conglomerados , Humanos , Monocitos/efectos de los fármacos , Monocitos/metabolismo , Nanopartículas/ultraestructura , Tamaño de la Partícula , Células THP-1
15.
BMC Cancer ; 19(1): 710, 2019 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-31319803

RESUMEN

BACKGROUND: One major hallmark of colorectal cancers (CRC) is genomic instability with its contribution to tumor heterogeneity and therapy resistance. To facilitate the investigation of intra-sample phenotypes and the de novo identification of tumor sub-populations, imaging mass spectrometry (IMS) provides a powerful technique to elucidate the spatial distribution patterns of peptides and proteins in tissue sections. METHODS: In the present study, we analyzed an in-house compiled tissue microarray (n = 60) comprising CRCs and control tissues by IMS. After obtaining protein profiles through direct analysis of tissue sections, two validation sets were used for immunohistochemical evaluation. RESULTS: A total of 28 m/z values in the mass range 800-3500 Da distinguished euploid from aneuploid CRCs (p < 0.001, ROC AUC values < 0.385 or > 0.635). After liquid chromatograph-mass spectrometry identification, UBE2N could be successfully validated by immunohistochemistry in the initial sample cohort (p = 0.0274, ROC AUC = 0.7937) and in an independent sample set of 90 clinical specimens (p = 0.0070, ROC AUC = 0.6957). CONCLUSIONS: The results showed that FFPE protein expression profiling of surgically resected CRC tissue extracts by MALDI-TOF MS has potential value for improved molecular classification. Particularly, the protein expression of UBE2N was validated in an independent clinical cohort to distinguish euploid from aneuploid CRCs.


Asunto(s)
Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Inestabilidad Genómica , Enzimas Ubiquitina-Conjugadoras/metabolismo , Anciano , Aneuploidia , Área Bajo la Curva , Biomarcadores de Tumor/metabolismo , Cromatografía Liquida , Estudios de Cohortes , Neoplasias Colorrectales/cirugía , Femenino , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Proteómica/métodos , Curva ROC , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Espectrometría de Masas en Tándem , Distribución Tisular
16.
Biochem Biophys Res Commun ; 508(3): 756-761, 2019 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-30528389

RESUMEN

Guanine-quadruplex (G-quadruplex) structures in mRNAs have been shown to modulate gene expression. However, the overall biological relevance of this process is under debate, as cellular helicases unwind G-quadruplex structures. The helicase Rhau (encoded by the DHX36 gene) was reported to be the major source of RNA G-quadruplex resolving activity in lysates of human cells. In the current study, we depleted Rhau by RNAi-mediated silencing and analyzed the effect on proteins whose mRNAs harbor a G-quadruplex motif in their 5'-UTRs. A targeted investigation of the proto-oncogenes Bcl-2 and NRAS, which are well-known examples for the translational repression of G-quadruplex structures, did not reveal effects caused by Rhau silencing. We therefore carried out a global analysis of changes in protein levels by label-free quantification using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Following Rhau knockdown, of all the identified proteins, only 1.9% were significantly downregulated to at least 70%. According to a bioinformatic analysis with the QGRS mapper, 33% of the downregulated proteins were predicted to harbor a G-quadruplex motif in the 5'-UTR of their respective mRNAs, compared to only 11% in the complete dataset. This indicates that in an unexpectedly small set of genes, in which G-quadruplex motifs are unusually common in the 5'-UTR of their mRNAs, Rhau helicase is responsible for the regulation of their expression.


Asunto(s)
Regiones no Traducidas 5'/genética , ARN Helicasas DEAD-box/genética , G-Cuádruplex , Técnicas de Silenciamiento del Gen , Interferencia de ARN , Supervivencia Celular , Regulación hacia Abajo/genética , GTP Fosfohidrolasas/metabolismo , Células HEK293 , Humanos , Proteínas de la Membrana/metabolismo , Biosíntesis de Proteínas , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Interferente Pequeño/metabolismo
17.
Nat Commun ; 9(1): 1235, 2018 03 26.
Artículo en Inglés | MEDLINE | ID: mdl-29581509

RESUMEN

About half of mammalian miRNA genes lie within introns of protein-coding genes, yet little is known about functional interactions between miRNAs and their host genes. The intronic miRNA miR-128 regulates neuronal excitability and dendritic morphology of principal neurons during mouse cerebral cortex development. Its conserved host genes, R3hdm1 and Arpp21, are predicted RNA-binding proteins. Here we use iCLIP to characterize ARPP21 recognition of uridine-rich sequences with high specificity for 3'UTRs. ARPP21 antagonizes miR-128 activity by co-regulating a subset of miR-128 target mRNAs enriched for neurodevelopmental functions. Protein-protein interaction data and functional assays suggest that ARPP21 acts as a positive post-transcriptional regulator by interacting with the translation initiation complex eIF4F. This molecular antagonism is reflected in inverse activities during dendritogenesis: miR-128 overexpression or knockdown of ARPP21 reduces dendritic complexity; ectopic ARPP21 leads to an increase. Thus, we describe a unique example of convergent function by two products of a single gene.


Asunto(s)
Dendritas/fisiología , MicroARNs/genética , Fosfoproteínas/fisiología , Proteínas de Unión al ARN/fisiología , Regiones no Traducidas 3' , Animales , Gránulos Citoplasmáticos/metabolismo , Factor 4F Eucariótico de Iniciación/metabolismo , Técnicas de Silenciamiento del Gen , Células HEK293 , Células HeLa , Humanos , Ratones , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Mapas de Interacción de Proteínas , Proteolisis , Procesamiento Postranscripcional del ARN , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo
18.
Sci Rep ; 8(1): 1916, 2018 01 30.
Artículo en Inglés | MEDLINE | ID: mdl-29382944

RESUMEN

Regulated intramembrane proteolysis of the amyloid precursor protein (APP) and its homologs, the APP like proteins APLP1 and APLP2, is typically a two-step process, which is initiated by ectodomain-shedding of the substrates by α- or ß-secretases. Growing evidence, however, indicates that the cleavage process for APLP1 is different than for APP. Here, we describe that full-length APLP1, but not APP or APLP2, is uniquely cleaved by γ-secretase without previous ectodomain shedding. The new fragment, termed sAPLP1γ, was exclusively associated with APLP1, not APP, APLP2. We provide an exact molecular analysis showing that sAPLP1γ was uniquely generated by γ-secretase from full-length APLP1. Mass spectrometry analysis showed that the sAPLP1γ fragment and the longest Aß-like peptide share the C-terminus. This novel mechanism of γ-secretase action is consistent with an ϵ-cut based upon the nature of the reaction in APP. We further demonstrate that the APLP1 transmembrane sequence is the critical determinant for γ-shedding and release of full-length APLP1. Moreover, the APLP1 TMS is sufficient to convert larger type-I membrane proteins like APP into direct γ-secretase substrates. Taken together, the direct cleavage of APLP1 is a novel feature of the γ-secretase prompting a re-thinking of γ-secretase activity modulation as a therapeutic strategy for Alzheimer disease.


Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Proteínas de la Membrana/metabolismo , Línea Celular , Células HEK293 , Humanos
19.
J Infect Dis ; 218(2): 291-299, 2018 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-29471363

RESUMEN

Lysyl-phosphatidylglycerol is one of the components of the mycobacterial membrane that contributes to the resistance to cationic antimicrobial peptides, a host-induced frontline defense against invading pathogens. Its production is catalyzed by LysX, a bifunctional protein with lysyl transferase and lysyl transfer RNA synthetase activity. Comparative proteome analysis of a lysX mutant of Mycobacterium avium strain 104 and the wild type indicated that the lysX mutant strain undergoes a transition in phenotype by switching the carbon metabolism to ß-oxidation of fatty acids, along with accumulation of lipid inclusions. Surprisingly, proteins associated with intracellular survival were upregulated in the lysX mutant, even during extracellular growth, preparing bacteria for the conditions occurring inside host cells. In line with this, the lysX mutant exhibited enhanced intracellular growth in human-blood-derived monocytes. Thus, our study exposes the significance of lysX in the metabolism and virulence of the environmental pathogen M. avium hominissuis.


Asunto(s)
Regulación Bacteriana de la Expresión Génica , Lisina-ARNt Ligasa/análisis , Metabolismo , Mycobacterium avium/crecimiento & desarrollo , Mycobacterium avium/metabolismo , Proteoma/análisis , Carbono/metabolismo , Humanos , Metabolismo de los Lípidos , Lisina-ARNt Ligasa/deficiencia , Monocitos/microbiología , Mycobacterium avium/química , Mycobacterium avium/genética , Oxidación-Reducción , Virulencia
20.
Bioengineering (Basel) ; 5(1)2018 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-29351237

RESUMEN

Eptacog alfa (NovoSeven®) is a vitamin K-dependent recombinant Factor VIIa produced by genetic engineering from baby hamster kidney (BHK) cells as a single peptide chain of 406 residues. After activation, it consists of a light chain (LC) of 152 amino and a heavy chain (HC) of 254 amino acids. Recombinant FVIIa undergoes many post-translational modifications (PTMs). The first ten glutamic acids of the N-terminal moiety are γ-carboxylated, Asn145 and Asn322 are N-glycosylated, and Ser52 and Ser60 are O-glycosylated. A head-to-head biosimilarity study was conducted for the originator and the first biosimilar AryoSeven™ to evaluate comparable bioengineering. Physicochemical properties were analyzed based on mass spectrometry, including intact mass, PTMs and higher-order structure. Both biotherapeutics exhibit a batch-to-batch variability in their N-glycan profiles. N-Glycopeptide analysis with UHPLC-QTOF-MSE confirmed N-glycosylation sites as well as two different O-glycopeptide sites. Ser60 was found to be O-fucosylated and Ser52 had O-glucose or O-glucose-(xylose)1,2 motifs as glycan variants. Ion mobility spectrometry (TWIMS) and NMR spectroscopy data affirm close similarity of the higher-order structure of both biologicals. Potency of the biodrugs was analyzed by a coagulation assay demonstrating comparable bioactivity. Consequently, careful process optimization led to a stable production process of the biopharmaceuticals.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA