Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Más filtros

Banco de datos
Tipo de estudio
Tipo del documento
Asunto de la revista
País de afiliación
Intervalo de año de publicación
1.
Cell ; 186(2): 346-362.e17, 2023 01 19.
Artículo en Inglés | MEDLINE | ID: mdl-36638793

RESUMEN

Ribosomes frequently stall during mRNA translation, resulting in the context-dependent activation of quality control pathways to maintain proteostasis. However, surveillance mechanisms that specifically respond to stalled ribosomes with an occluded A site have not been identified. We discovered that the elongation factor-1α (eEF1A) inhibitor, ternatin-4, triggers the ubiquitination and degradation of eEF1A on stalled ribosomes. Using a chemical genetic approach, we unveiled a signaling network comprising two E3 ligases, RNF14 and RNF25, which are required for eEF1A degradation. Quantitative proteomics revealed the RNF14 and RNF25-dependent ubiquitination of eEF1A and a discrete set of ribosomal proteins. The ribosome collision sensor GCN1 plays an essential role by engaging RNF14, which directly ubiquitinates eEF1A. The site-specific, RNF25-dependent ubiquitination of the ribosomal protein RPS27A/eS31 provides a second essential signaling input. Our findings illuminate a ubiquitin signaling network that monitors the ribosomal A site and promotes the degradation of stalled translation factors, including eEF1A and the termination factor eRF1.


Asunto(s)
Proteínas de Unión al ARN , Transactivadores , Proteínas Portadoras/metabolismo , Factores de Elongación de Péptidos/genética , Biosíntesis de Proteínas , Proteínas Ribosómicas/metabolismo , Ribosomas/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitinación , Humanos , Células HeLa , Células HEK293 , Proteínas de Unión al ARN/metabolismo , Transactivadores/metabolismo , Factor 1 de Elongación Peptídica/metabolismo
2.
Nat Chem Biol ; 18(9): 934-941, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35590003

RESUMEN

The expansion of the target landscape of covalent inhibitors requires the engagement of nucleophiles beyond cysteine. Although the conserved catalytic lysine in protein kinases is an attractive candidate for a covalent approach, selectivity remains an obvious challenge. Moreover, few covalent inhibitors have been shown to engage the kinase catalytic lysine in animals. We hypothesized that reversible, lysine-targeted inhibitors could provide sustained kinase engagement in vivo, with selectivity driven in part by differences in residence time. By strategically linking benzaldehydes to a promiscuous kinase binding scaffold, we developed chemoproteomic probes that reversibly and covalently engage >200 protein kinases in cells and mice. Probe-kinase residence time was dramatically enhanced by a hydroxyl group ortho to the aldehyde. Remarkably, only a few kinases, including Aurora A, showed sustained, quasi-irreversible occupancy in vivo, the structural basis for which was revealed by X-ray crystallography. We anticipate broad application of salicylaldehyde-based probes to proteins that lack a druggable cysteine.


Asunto(s)
Lisina , Inhibidores de Proteínas Quinasas , Animales , Cisteína/metabolismo , Lisina/metabolismo , Ratones , Unión Proteica , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/metabolismo
3.
Elife ; 112022 10 20.
Artículo en Inglés | MEDLINE | ID: mdl-36264623

RESUMEN

Rapid and accurate mRNA translation requires efficient codon-dependent delivery of the correct aminoacyl-tRNA (aa-tRNA) to the ribosomal A site. In mammals, this fidelity-determining reaction is facilitated by the GTPase elongation factor-1 alpha (eEF1A), which escorts aa-tRNA as an eEF1A(GTP)-aa-tRNA ternary complex into the ribosome. The structurally unrelated cyclic peptides didemnin B and ternatin-4 bind to the eEF1A(GTP)-aa-tRNA ternary complex and inhibit translation but have different effects on protein synthesis in vitro and in vivo. Here, we employ single-molecule fluorescence imaging and cryogenic electron microscopy to determine how these natural products inhibit translational elongation on mammalian ribosomes. By binding to a common site on eEF1A, didemnin B and ternatin-4 trap eEF1A in an intermediate state of aa-tRNA selection, preventing eEF1A release and aa-tRNA accommodation on the ribosome. We also show that didemnin B and ternatin-4 exhibit distinct effects on the dynamics of aa-tRNA selection that inform on observed disparities in their inhibition efficacies and physiological impacts. These integrated findings underscore the value of dynamics measurements in assessing the mechanism of small-molecule inhibition and highlight potential of single-molecule methods to reveal how distinct natural products differentially impact the human translation mechanism.


Asunto(s)
Productos Biológicos , Aminoacil-ARN de Transferencia , Animales , Humanos , Productos Biológicos/metabolismo , Codón/metabolismo , Guanosina Trifosfato/metabolismo , Mamíferos/genética , Factor Tu de Elongación Peptídica/química , Factor Tu de Elongación Peptídica/genética , Factor Tu de Elongación Peptídica/metabolismo , Péptidos Cíclicos/farmacología , Péptidos Cíclicos/metabolismo , Ribosomas/metabolismo , Aminoacil-ARN de Transferencia/metabolismo
4.
Elife ; 42015 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-26651998

RESUMEN

Cyclic peptide natural products have evolved to exploit diverse protein targets, many of which control essential cellular processes. Inspired by a series of cyclic peptides with partially elucidated structures, we designed synthetic variants of ternatin, a cytotoxic and anti-adipogenic natural product whose molecular mode of action was unknown. The new ternatin variants are cytotoxic toward cancer cells, with up to 500-fold greater potency than ternatin itself. Using a ternatin photo-affinity probe, we identify the translation elongation factor-1A ternary complex (eEF1A·GTP·aminoacyl-tRNA) as a specific target and demonstrate competitive binding by the unrelated natural products, didemnin and cytotrienin. Mutations in domain III of eEF1A prevent ternatin binding and confer resistance to its cytotoxic effects, implicating the adjacent hydrophobic surface as a functional hot spot for eEF1A modulation. We conclude that the eukaryotic elongation factor-1A and its ternary complex with GTP and aminoacyl-tRNA are common targets for the evolution of cytotoxic natural products.


Asunto(s)
Antineoplásicos/farmacología , Muerte Celular , Factor 1 de Elongación Peptídica/antagonistas & inhibidores , Péptidos Cíclicos/farmacología , Antineoplásicos/síntesis química , Línea Celular Tumoral , Resistencia a Medicamentos , Guanosina Trifosfato/metabolismo , Humanos , Proteínas Mutantes/antagonistas & inhibidores , Proteínas Mutantes/genética , Mutación , Factor 1 de Elongación Peptídica/genética , Péptidos Cíclicos/síntesis química , Unión Proteica , ARN de Transferencia/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA