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










Base de dados
Intervalo de ano de publicação
1.
Nucleic Acids Res ; 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38811035

RESUMO

Ribosomes trapped on mRNAs during protein synthesis need to be rescued for the cell to survive. The most ubiquitous bacterial ribosome rescue pathway is trans-translation mediated by tmRNA and SmpB. Genetic inactivation of trans-translation can be lethal, unless ribosomes are rescued by ArfA or ArfB alternative rescue factors or the ribosome-associated quality control (RQC) system, which in Bacillus subtilis involves MutS2, RqcH, RqcP and Pth. Using transposon sequencing in a trans-translation-incompetent B. subtilis strain we identify a poorly characterized S4-domain-containing protein YlmH as a novel potential RQC factor. Cryo-EM structures reveal that YlmH binds peptidyl-tRNA-50S complexes in a position analogous to that of S4-domain-containing protein RqcP, and that, similarly to RqcP, YlmH can co-habit with RqcH. Consistently, we show that YlmH can assume the role of RqcP in RQC by facilitating the addition of poly-alanine tails to truncated nascent polypeptides. While in B. subtilis the function of YlmH is redundant with RqcP, our taxonomic analysis reveals that in multiple bacterial phyla RqcP is absent, while YlmH and RqcH are present, suggesting that in these species YlmH plays a central role in the RQC.

2.
J Clin Endocrinol Metab ; 105(1)2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31512719

RESUMO

CONTEXT: Clinically used endometrial (EM) receptivity assays are based on transcriptomic patterning of biopsies at midsecretory endometrium (MSE) to identify the possible displacement or disruption of window of implantation (WOI) in patients with recurrent implantation failure (RIF). However, biopsies are invasive and cannot be performed in the same cycle with in vitro fertilization embryo transfer, while uterine fluid (UF) analysis is considered minimally invasive and can immediately precede embryo transfer. OBJECTIVE: To determine whether UF proteome can be used for WOI monitoring and whether it would highlight the etiology of RIF. PATIENTS: Paired early secretory endometrial (ESE) and MSE UF samples from six fertile control women for discovery, and an additional 11 paired ESE/MSE samples from controls and 29 MSE samples from RIF patients for validation. RESULTS: Using discovery mass spectrometry (MS) proteomics we detected 3158 proteins from secretory phase UF of which 367 undergo significant (q < 0.05) proteomic changes while transitioning from ESE to MSE. Forty-five proteins were further validated with targeted MS, and 21 were found to display similar levels between control ESE and RIF MSE, indicating displacement of the WOI. A panel of PGR, NNMT, SLC26A2 and LCN2 demonstrated specificity and sensitivity of 91.7% for distinguishing MSE from ESE samples. The same panel distinguished control MSE samples from RIF MSE with a 91.7% specificity and 96.6% sensitivity. CONCLUSION: UF proteins can be used for estimating uterine receptivity with minimal invasiveness. Women with RIF appear to have altered MSE UF profiles that may contribute to their low IVF success rate.


Assuntos
Biomarcadores/metabolismo , Líquidos Corporais/metabolismo , Implantação do Embrião/fisiologia , Endométrio/fisiologia , Proteoma/metabolismo , Útero/metabolismo , Adulto , Biomarcadores/análise , Estudos de Casos e Controles , Estudos de Coortes , Transferência Embrionária , Feminino , Fertilização in vitro , Seguimentos , Humanos , Proteoma/análise
3.
Biochimie ; 156: 79-91, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30315853

RESUMO

MazEF and MqsRA are toxin-antitoxin systems, where the toxins MazF and MqsR sequence-specifically cleave single-stranded RNA, thereby shutting down protein synthesis and cell growth. However, it has been proposed that MazF functions in a highly specific pathway, where it truncates the 5' ends of a set of E. coli transcripts (the MazF regulon), which are then translated under stress conditions by specialized ribosomes. We mapped the cleavage sites of MazF and MqsR throughout the E. coli transcriptome. Our results show that both toxins cleave mRNA independently of the recognition site position and MazF freely cleaves transcripts of the proposed MazF regulon within coding sequences. Proteome analysis indicated that MazF expression leads to overall inhibition of protein synthesis and the putative MazF regulon proteins are not selectively synthesized in response to the toxin. Our results support a simpler role for endoribonuclease TA systems as indifferent destroyers of unstructured RNA.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Endorribonucleases/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Estabilidade de RNA/fisiologia , RNA Bacteriano/metabolismo , RNA Mensageiro/metabolismo , Proteínas de Ligação a DNA/genética , Endorribonucleases/genética , Escherichia coli/genética , Proteínas de Escherichia coli/genética , RNA Bacteriano/genética , RNA Mensageiro/genética
4.
Biochemistry ; 57(37): 5456-5465, 2018 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-30096229

RESUMO

Serine/threonine protein kinase ULK3 is implicated in a variety of cellular processes, including autophagy, cell division, and execution of the Sonic hedgehog pathway. However, very little about how its biological activity could be controlled is known. This study focuses on unraveling biochemical insights into the mechanism of inhibition and activation of ULK3. We identify novel phosphorylation sites in ULK3 and show that autophosphorylation has no impact on the kinase activity of the protein. We further demonstrate that phosphorylation of two residues in the kinase domain of ULK3 by an as yet unidentified kinase may completely abolishes its catalytic activity. We show that a low-molecular weight inhibitor SU6668, designed as an ATP competitive inhibitor for tyrosine kinases, binds in the ATP pocket of ULK3 yet inhibits ULK3 kinase activity in a partially ATP noncompetitive manner. Finally, we demonstrate that the ULK3 kinase domain, annotated in silico, is not sufficient for its kinase activity, and additional amino acids in the 271-300 region are required.


Assuntos
Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Indóis/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Pirróis/farmacologia , Sequência de Aminoácidos , Domínio Catalítico , Humanos , Modelos Moleculares , Mutagênese Sítio-Dirigida , Mutação , Oxindóis , Fosforilação , Propionatos , Conformação Proteica , Proteínas Serina-Treonina Quinases/genética , Homologia de Sequência , Transdução de Sinais
5.
Acta Trop ; 127(2): 136-42, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23632259

RESUMO

Cystic echinococcosis (hydatidosis) is a severe and widespread disease, caused by the larval stage of the tapeworm Echinococcus granulosus; it affects large numbers of humans and farm animals annually, causing serious health and economic problems. Molecular studies have identified large genetic variation within the E. granulosus complex, with various hosts displaying different susceptibility to different genotypes. For the effective management of the disease, one of the most pressing tasks is to combine epidemiological and genetic data to better understand the role of different hosts and genotypes in the transmission of the parasite. The aim of the present study was to describe the epidemiology of cystic echinococcosis in cattle and sheep, and to characterise the genotypes of E. granulosus present in these farm animals. The study was carried out in the Pampa region of Argentina, with a particular focus on Buenos Aires province, where cystic echinococcosis represents an important human and veterinary health problem. Among 513 cattle and 792 sheep, 11.9% and 4.0%, respectively, were infected with E. granulosus. Genetic characterisation of 42 isolates from cattle and 34 isolates from sheep was carried out by sequencing mitochondrial cox1 and nad1 genes. The vast majority of isolates were identified as genotype G1, except for a single sheep isolate determined as genotype G2, and a single cattle isolate that corresponded to genotype G5. Genotype G1 has previously been found to be the most infectious genotype to humans. As G1 was also the genotype principally responsible for cystic echinococcosis in Buenos Aires province, these results have important implications for developing effective disease control programmes to improve human and animal healthcare in this region.


Assuntos
Doenças dos Bovinos/parasitologia , Equinococose Hepática/veterinária , Echinococcus granulosus/genética , Doenças dos Ovinos/parasitologia , Animais , Argentina/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Equinococose Hepática/epidemiologia , Equinococose Hepática/parasitologia , Genótipo , Filogenia , Ovinos , Doenças dos Ovinos/epidemiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...