Doa10p ubiquitin ligase complex / nuclear inner membrane / retrograde protein transport, ER to cytosol / ERAD pathway / RING-type E3 ubiquitin transferase / ubiquitin-protein transferase activity / ubiquitin protein ligase activity / nuclear envelope / protein ubiquitination / endoplasmic reticulum membrane ...Doa10p ubiquitin ligase complex / nuclear inner membrane / retrograde protein transport, ER to cytosol / ERAD pathway / RING-type E3 ubiquitin transferase / ubiquitin-protein transferase activity / ubiquitin protein ligase activity / nuclear envelope / protein ubiquitination / endoplasmic reticulum membrane / endoplasmic reticulum / zinc ion binding / membrane 類似検索 - 分子機能
RING-variant domain / Zinc finger RING-CH-type profile. / Zinc finger, RING-CH-type / The RING-variant domain is a C4HC3 zinc-finger like motif found in a number of cellular and viral proteins. Some of these proteins have been shown both in vivo and in vitro to have ubiquitin E3 ligase activity. / Zinc finger, RING/FYVE/PHD-type 類似検索 - ドメイン・相同性
ジャーナル: Nat Commun / 年: 2024 タイトル: Doa10/MARCH6 architecture interconnects E3 ligase activity with lipid-binding transmembrane channel to regulate SQLE. 著者: J Josephine Botsch / Roswitha Junker / Michèle Sorgenfrei / Patricia P Ogger / Luca Stier / Susanne von Gronau / Peter J Murray / Markus A Seeger / Brenda A Schulman / Bastian Bräuning / 要旨: Transmembrane E3 ligases play crucial roles in homeostasis. Much protein and organelle quality control, and metabolic regulation, are determined by ER-resident MARCH6 E3 ligases, including Doa10 in ...Transmembrane E3 ligases play crucial roles in homeostasis. Much protein and organelle quality control, and metabolic regulation, are determined by ER-resident MARCH6 E3 ligases, including Doa10 in yeast. Here, we present Doa10/MARCH6 structural analysis by cryo-EM and AlphaFold predictions, and a structure-based mutagenesis campaign. The majority of Doa10/MARCH6 adopts a unique circular structure within the membrane. This channel is established by a lipid-binding scaffold, and gated by a flexible helical bundle. The ubiquitylation active site is positioned over the channel by connections between the cytosolic E3 ligase RING domain and the membrane-spanning scaffold and gate. Here, by assaying 95 MARCH6 variants for effects on stability of the well-characterized substrate SQLE, which regulates cholesterol levels, we reveal crucial roles of the gated channel and RING domain consistent with AlphaFold-models of substrate-engaged and ubiquitylation complexes. SQLE degradation further depends on connections between the channel and RING domain, and lipid binding sites, revealing how interconnected Doa10/MARCH6 elements could orchestrate metabolic signals, substrate binding, and E3 ligase activity.