RESUMO
Control of mRNA levels, a fundamental aspect in the regulation of gene expression, is achieved through a balance between mRNA synthesis and decay. E26-related gene (Erg) proteins are canonical transcription factors whose previously described functions are confined to the control of mRNA synthesis. Here, we report that ERG also regulates gene expression by affecting mRNA stability and identify the molecular mechanisms underlying this function in human cells. ERG is recruited to mRNAs via interaction with the RNA-binding protein RBPMS, and it promotes mRNA decay by binding CNOT2, a component of the CCR4-NOT deadenylation complex. Transcriptome-wide mRNA stability analysis revealed that ERG controls the degradation of a subset of mRNAs highly connected to Aurora signaling, whose decay during S phase is necessary for mitotic progression. Our data indicate that control of gene expression by mammalian transcription factors may follow a more complex scheme than previously anticipated, integrating mRNA synthesis and degradation.
Assuntos
Mitose , Processamento Pós-Transcricional do RNA , RNA Mensageiro/genética , Proteínas de Ligação a RNA/genética , Proteínas Repressoras/genética , Aurora Quinases/genética , Aurora Quinases/metabolismo , Linhagem Celular Tumoral , Fibroblastos/citologia , Fibroblastos/metabolismo , Células HEK293 , Células HeLa , Humanos , Osteoblastos/citologia , Osteoblastos/metabolismo , Proteína Proto-Oncogênica c-fli-1/genética , Proteína Proto-Oncogênica c-fli-1/metabolismo , Estabilidade de RNA , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/metabolismo , Transdução de Sinais , Regulador Transcricional ERG/antagonistas & inibidores , Regulador Transcricional ERG/genética , Regulador Transcricional ERG/metabolismoRESUMO
Lipid microdomains (rafts) are cholesterol-enriched dynamic ordered lipid domains belonging to cell membranes involved in diverse cellular functions, including signal transduction, membrane trafficking, and infection. Many studies have reported relationships between insulin signaling and lipid rafts. Likewise, links between insulin signaling and O-GlcNAcylation have also been described. However, the potential connection between O-GlcNAc and raft dynamics remains unexplored. Here we show that O-GlcNAc and the enzyme that creates this modification, O-GlcNAc transferase (OGT), are localized in rafts. On insulin stimulation, we observe time-dependent increases in OGT expression and localization within rafts. We show that these processes depend on activation of the phosphatidylinositol 3-kinase (PI3K) pathway. Inhibition of OGT does not significantly affect cholesterol synthesis and raft building but decreases insulin receptor expression and PI3K and mitogen-activated protein kinase pathway activation. Taken together, these findings indicate that O-GlcNAcylation, lipid rafts, and signaling pathways are spatiotemporally coordinated to enable fundamental cellular functions.