RESUMEN
Cyclic GMP-AMP synthase (cGAS) is a key sensor responsible for cytosolic DNA detection. Here we report that GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) is critical for DNA sensing and efficient activation of cGAS. G3BP1 enhanced DNA binding of cGAS by promoting the formation of large cGAS complexes. G3BP1 deficiency led to inefficient DNA binding by cGAS and inhibited cGAS-dependent interferon (IFN) production. The G3BP1 inhibitor epigallocatechin gallate (EGCG) disrupted existing G3BP1-cGAS complexes and inhibited DNA-triggered cGAS activation, thereby blocking DNA-induced IFN production both in vivo and in vitro. EGCG administration blunted self DNA-induced autoinflammatory responses in an Aicardi-Goutières syndrome (AGS) mouse model and reduced IFN-stimulated gene expression in cells from a patient with AGS. Thus, our study reveals that G3BP1 physically interacts with and primes cGAS for efficient activation. Furthermore, EGCG-mediated inhibition of G3BP1 provides a potential treatment for cGAS-related autoimmune diseases.
Asunto(s)
Enfermedades Autoinmunes del Sistema Nervioso/metabolismo , ADN Helicasas/metabolismo , Complejos Multiproteicos/metabolismo , Malformaciones del Sistema Nervioso/metabolismo , Nucleotidiltransferasas/metabolismo , Proteínas de Unión a Poli-ADP-Ribosa/metabolismo , ARN Helicasas/metabolismo , Proteínas con Motivos de Reconocimiento de ARN/metabolismo , Animales , Autoantígenos/inmunología , Autoantígenos/metabolismo , Enfermedades Autoinmunes del Sistema Nervioso/tratamiento farmacológico , Enfermedades Autoinmunes del Sistema Nervioso/genética , Catequina/análogos & derivados , Catequina/uso terapéutico , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Citosol/inmunología , Citosol/metabolismo , ADN/inmunología , ADN/metabolismo , ADN Helicasas/antagonistas & inhibidores , ADN Helicasas/genética , Modelos Animales de Enfermedad , Exodesoxirribonucleasas/genética , Células HEK293 , Células HeLa , Humanos , Interferones/metabolismo , Ratones , Ratones Noqueados , Malformaciones del Sistema Nervioso/tratamiento farmacológico , Malformaciones del Sistema Nervioso/genética , Fármacos Neuroprotectores/uso terapéutico , Fosfoproteínas/genética , Proteínas de Unión a Poli-ADP-Ribosa/antagonistas & inhibidores , Proteínas de Unión a Poli-ADP-Ribosa/genética , Unión Proteica , ARN Helicasas/antagonistas & inhibidores , ARN Helicasas/genética , Proteínas con Motivos de Reconocimiento de ARN/antagonistas & inhibidores , Proteínas con Motivos de Reconocimiento de ARN/genéticaRESUMEN
Cyclic GMP-AMP synthase (cGAS) functions as a key sensor for microbial invasion and cellular damage by detecting emerging cytosolic DNA. Here, we report that GTPase-activating protein-(SH3 domain)-binding protein 1 (G3BP1) primes cGAS for its prompt activation by engaging cGAS in a primary liquid-phase condensation state. Using high-resolution microscopy, we show that in resting cells, cGAS exhibits particle-like morphological characteristics, which are markedly weakened when G3BP1 is deleted. Upon DNA challenge, the pre-condensed cGAS undergoes liquid-liquid phase separation (LLPS) more efficiently. Importantly, G3BP1 deficiency or its inhibition dramatically diminishes DNA-induced LLPS and the subsequent activation of cGAS. Interestingly, RNA, previously reported to form condensates with cGAS, does not activate cGAS. Accordingly, we find that DNA - but not RNA - treatment leads to the dissociation of G3BP1 from cGAS. Taken together, our study shows that the primary condensation state of cGAS is critical for its rapid response to DNA.
Asunto(s)
ADN Helicasas , Nucleotidiltransferasas , Proteínas de Unión a Poli-ADP-Ribosa , ARN Helicasas , Proteínas con Motivos de Reconocimiento de ARN , ADN/metabolismo , ADN Helicasas/genética , ADN Helicasas/metabolismo , Nucleotidiltransferasas/metabolismo , Proteínas de Unión a Poli-ADP-Ribosa/genética , Proteínas de Unión a Poli-ADP-Ribosa/metabolismo , ARN Helicasas/genética , ARN Helicasas/metabolismo , Proteínas con Motivos de Reconocimiento de ARN/genética , Proteínas con Motivos de Reconocimiento de ARN/metabolismo , Gránulos de EstrésRESUMEN
Lack of detailed knowledge of SARS-CoV-2 infection has been hampering the development of treatments for coronavirus disease 2019 (COVID-19). Here, we report that RNA triggers the liquid-liquid phase separation (LLPS) of the SARS-CoV-2 nucleocapsid protein, N. By analyzing all 29 proteins of SARS-CoV-2, we find that only N is predicted as an LLPS protein. We further confirm the LLPS of N during SARS-CoV-2 infection. Among the 100,849 genome variants of SARS-CoV-2 in the GISAID database, we identify that ~37% (36,941) of the genomes contain a specific trio-nucleotide polymorphism (GGG-to-AAC) in the coding sequence of N, which leads to the amino acid substitutions, R203K/G204R. Interestingly, NR203K/G204R exhibits a higher propensity to undergo LLPS and a greater effect on IFN inhibition. By screening the chemicals known to interfere with N-RNA binding in other viruses, we find that (-)-gallocatechin gallate (GCG), a polyphenol from green tea, disrupts the LLPS of N and inhibits SARS-CoV-2 replication. Thus, our study reveals that targeting N-RNA condensation with GCG could be a potential treatment for COVID-19.