Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Life Sci Alliance ; 7(8)2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38858088

RESUMO

The signal recognition particle is essential for targeting transmembrane and secreted proteins to the endoplasmic reticulum. Remarkably, because they work together in the cytoplasm, the SRP and ribosomes are assembled in the same biomolecular condensate: the nucleolus. How important is the nucleolus for SRP assembly is not known. Using quantitative proteomics, we have investigated the interactomes of SRP components. We reveal that SRP proteins are associated with scores of nucleolar proteins important for ribosome biogenesis and nucleolar structure. Having monitored the subcellular distribution of SRP proteins upon controlled nucleolar disruption, we conclude that an intact organelle is required for their proper localization. Lastly, we have detected two SRP proteins in Cajal bodies, which indicates that previously undocumented steps of SRP assembly may occur in these bodies. This work highlights the importance of a structurally and functionally intact nucleolus for efficient SRP production and suggests that the biogenesis of SRP and ribosomes may be coordinated in the nucleolus by common assembly factors.


Assuntos
Nucléolo Celular , Proteômica , Ribossomos , Partícula de Reconhecimento de Sinal , Partícula de Reconhecimento de Sinal/metabolismo , Nucléolo Celular/metabolismo , Ribossomos/metabolismo , Humanos , Proteômica/métodos , Proteínas Nucleares/metabolismo , Corpos Enovelados/metabolismo , Células HeLa , Retículo Endoplasmático/metabolismo
2.
Nucleic Acids Res ; 51(7): 3357-3374, 2023 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-36869663

RESUMO

The conserved H/ACA RNPs consist of one H/ACA RNA and 4 core proteins: dyskerin, NHP2, NOP10, and GAR1. Its assembly requires several assembly factors. A pre-particle containing the nascent RNAs, dyskerin, NOP10, NHP2 and NAF1 is assembled co-transcriptionally. NAF1 is later replaced by GAR1 to form mature RNPs. In this study, we explore the mechanism leading to the assembly of H/ACA RNPs. We performed the analysis of GAR1, NHP2, SHQ1 and NAF1 proteomes by quantitative SILAC proteomic, and analyzed purified complexes containing these proteins by sedimentation on glycerol gradient. We propose the formation of several distinct intermediate complexes during H/ACA RNP assembly, notably the formation of early protein-only complexes containing at least the core proteins dyskerin, NOP10, and NHP2, and the assembly factors SHQ1 and NAF1. We also identified new proteins associated with GAR1, NHP2, SHQ1 and NAF1, which can be important for box H/ACA assembly or function. Moreover, even though GAR1 is regulated by methylations, the nature, localization, and functions of these methylations are not well known. Our MS analysis of purified GAR1 revealed new sites of arginine methylations. Additionally, we showed that unmethylated GAR1 is correctly incorporated in H/ACA RNPs, even though with less efficiency than methylated ones.


Assuntos
Proteômica , Ribonucleoproteínas , Ribonucleoproteínas/genética , Ribonucleoproteínas Nucleolares Pequenas/genética , Ribonucleoproteínas Nucleolares Pequenas/metabolismo , Proteínas de Ligação a RNA , RNA/genética
3.
J Radiat Res ; 64(2): 304-316, 2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-36680763

RESUMO

Irradiated cells can propagate signals to neighboring cells. Manifestations of these so-called bystander effects (BEs) are thought to be relatively more important after exposure to low- vs high-dose radiation and can be mediated via the release of secreted molecules, including inflammatory cytokines, from irradiated cells. Thus, BEs can potentially modify the inflammatory environment of irradiated cells. To determine whether these modifications could affect the functionality of bystander immune cells and their inflammatory response, we analyzed and compared the in vitro response of primary human fibroblasts and keratinocytes to low and high doses of radiation and assessed their ability to modulate the inflammatory activation of peripheral blood mononuclear cells (PBMCs). Only high-dose exposure resulted in either up- or down-regulation of selected inflammatory genes. In conditioned culture media transfer experiments, radiation-induced bystander signals elicited from irradiated fibroblasts and keratinocytes were found to modulate the transcription of inflammatory mediator genes in resting PBMCs, and after activation of PBMCs stimulated with lipopolysaccharide (LPS), a strong inflammatory agent. Radiation-induced BEs induced from skin cells can therefore act as a modifier of the inflammatory response of bystander immune cells and affect their functionality.


Assuntos
Efeito Espectador , Leucócitos Mononucleares , Humanos , Queratinócitos , Fibroblastos , Relação Dose-Resposta à Radiação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...