diacylglycerol-dependent serine/threonine kinase activity / chromatoid body / eye development / regulation of protein kinase activity / regulation of telomere maintenance / nuclear-transcribed mRNA catabolic process, nonsense-mediated decay / telomeric DNA binding / phosphatidylinositol phosphate biosynthetic process / Nonsense Mediated Decay (NMD) enhanced by the Exon Junction Complex (EJC) / mRNA export from nucleus ...diacylglycerol-dependent serine/threonine kinase activity / chromatoid body / eye development / regulation of protein kinase activity / regulation of telomere maintenance / nuclear-transcribed mRNA catabolic process, nonsense-mediated decay / telomeric DNA binding / phosphatidylinositol phosphate biosynthetic process / Nonsense Mediated Decay (NMD) enhanced by the Exon Junction Complex (EJC) / mRNA export from nucleus / brain development / heart development / peptidyl-serine phosphorylation / in utero embryonic development / protein autophosphorylation / non-specific serine/threonine protein kinase / protein kinase activity / DNA repair / protein serine kinase activity / protein serine/threonine kinase activity / DNA damage response / negative regulation of apoptotic process / RNA binding / nucleoplasm / ATP binding / identical protein binding / nucleus / metal ion binding / cytoplasm / cytosol 類似検索 - 分子機能
ジャーナル: Cell Res / 年: 2019 タイトル: Cryo-EM structure of SMG1-SMG8-SMG9 complex. 著者: Li Zhu / Liang Li / Yilun Qi / Zishuo Yu / Yanhui Xu / 要旨: Nonsense-mediated mRNA decay (NMD) targets premature stop codon (PTC)-containing mRNAs for rapid degradation, and is essential for mammalian embryonic development, brain development and modulation of ...Nonsense-mediated mRNA decay (NMD) targets premature stop codon (PTC)-containing mRNAs for rapid degradation, and is essential for mammalian embryonic development, brain development and modulation of the stress response. The key event in NMD is the SMG1-mediated phosphorylation of an RNA helicase UPF1 and SMG1 kinase activity is inhibited by SMG8 and SMG9 in an unknown mechanism. Here, we determined the cryo-EM structures of human SMG1 at 3.6 Å resolution and the SMG1-SMG8-SMG9 complex at 3.4 Å resolution, respectively. SMG8 has a C-terminal kinase inhibitory domain (KID), which covers the catalytic pocket and inhibits the kinase activity of SMG1. Structural analyses suggest that GTP hydrolysis of SMG9 would lead to a dramatic conformational change of SMG8-SMG9 and the KID would move away from the inhibitory position to restore SMG1 kinase activity. Thus, our structural and biochemical analyses provide a mechanistic understanding of SMG1-SMG8-SMG9 complex assembly and the regulatory mechanism of SMG1 kinase activity.