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 / cytosol / cytoplasm 類似検索 - 分子機能
ジャーナル: Elife / 年: 2021 タイトル: Cryo-EM reconstructions of inhibitor-bound SMG1 kinase reveal an autoinhibitory state dependent on SMG8. 著者: Lukas M Langer / Fabien Bonneau / Yair Gat / Elena Conti / 要旨: The PI3K-related kinase (PIKK) SMG1 monitors the progression of metazoan nonsense-mediated mRNA decay (NMD) by phosphorylating the RNA helicase UPF1. Previous work has shown that the activity of SMG1 ...The PI3K-related kinase (PIKK) SMG1 monitors the progression of metazoan nonsense-mediated mRNA decay (NMD) by phosphorylating the RNA helicase UPF1. Previous work has shown that the activity of SMG1 is impaired by small molecule inhibitors, is reduced by the SMG1 interactors SMG8 and SMG9, and is downregulated by the so-called SMG1 insertion domain. However, the molecular basis for this complex regulatory network has remained elusive. Here, we present cryo-electron microscopy reconstructions of human SMG1-9 and SMG1-8-9 complexes bound to either a SMG1 inhibitor or a non-hydrolyzable ATP analog at overall resolutions ranging from 2.8 to 3.6 Å. These structures reveal the basis with which a small molecule inhibitor preferentially targets SMG1 over other PIKKs. By comparison with our previously reported substrate-bound structure (Langer et al.,2020), we show that the SMG1 insertion domain can exert an autoinhibitory function by directly blocking the substrate-binding path as well as overall access to the SMG1 kinase active site. Together with biochemical analysis, our data indicate that SMG1 autoinhibition is stabilized by the presence of SMG8. Our results explain the specific inhibition of SMG1 by an ATP-competitive small molecule, provide insights into regulation of its kinase activity within the NMD pathway, and expand the understanding of PIKK regulatory mechanisms in general.