ジャーナル: Structure / 年: 2023 タイトル: Cryo-EM structure of the KLHL22 E3 ligase bound to an oligomeric metabolic enzyme. 著者: Fei Teng / Yang Wang / Ming Liu / Shuyun Tian / Goran Stjepanovic / Ming-Yuan Su / 要旨: CULLIN-RING ligases constitute the largest group of E3 ubiquitin ligases. While some CULLIN family members recruit adapters before engaging further with different substrate receptors, homo-dimeric ...CULLIN-RING ligases constitute the largest group of E3 ubiquitin ligases. While some CULLIN family members recruit adapters before engaging further with different substrate receptors, homo-dimeric BTB-Kelch family proteins combine adapter and substrate receptor into a single polypeptide for the CULLIN3 family. However, the entire structural assembly and molecular details have not been elucidated to date. Here, we present a cryo-EM structure of the CULLIN3 in complex with Kelch-like protein 22 (KLHL22) and a mitochondrial glutamate dehydrogenase complex I (GDH1) at 3.06 Å resolution. The structure adopts a W-shaped architecture formed by E3 ligase dimers. Three CULLIN3 dimers were found to be dynamically associated with a single GDH1 hexamer. CULLIN3 ligase mediated the polyubiquitination of GDH1 in vitro. Together, these results enabled the establishment of a structural model for understanding the complete assembly of BTB-Kelch proteins with CULLIN3 and how together they recognize oligomeric substrates and target them for ubiquitination.