ジャーナル: Nat Commun / 年: 2025 タイトル: Structural mechanisms for centrosomal recruitment and organization of the microtubule nucleator γ-TuRC. 著者: Qi Gao / Florian W Hofer / Sebastian Filbeck / Bram J A Vermeulen / Martin Würtz / Annett Neuner / Charlotte Kaplan / Maja Zezlina / Cornelia Sala / Hyesu Shin / Oliver J Gruss / Elmar ...著者: Qi Gao / Florian W Hofer / Sebastian Filbeck / Bram J A Vermeulen / Martin Würtz / Annett Neuner / Charlotte Kaplan / Maja Zezlina / Cornelia Sala / Hyesu Shin / Oliver J Gruss / Elmar Schiebel / Stefan Pfeffer / 要旨: The γ-tubulin ring complex (γ-TuRC) acts as a structural template for microtubule formation at centrosomes, associating with two main compartments: the pericentriolar material and the centriole ...The γ-tubulin ring complex (γ-TuRC) acts as a structural template for microtubule formation at centrosomes, associating with two main compartments: the pericentriolar material and the centriole lumen. In the pericentriolar material, the γ-TuRC is involved in microtubule organization, while the function of the centriole lumenal pool remains unclear. The conformational landscape of the γ-TuRC, which is crucial for its activity, and its centrosomal anchoring mechanisms, which determine γ-TuRC activity and turnover, are not understood. Using cryo-electron tomography, we analyze γ-TuRCs in human cells and purified centrosomes. Pericentriolar γ-TuRCs simultaneously associate with the essential adapter NEDD1 and the microcephaly protein CDK5RAP2. NEDD1 forms a tetrameric structure at the γ-TuRC base through interactions with four GCP3/MZT1 modules and GCP5/6-specific extensions, while multiple copies of CDK5RAP2 engage the γ-TuRC in two distinct binding patterns to promote γ-TuRC closure and activation. In the centriole lumen, the microtubule branching factor Augmin tethers a condensed cluster of γ-TuRCs to the centriole wall with defined directional orientation. Centriole-lumenal γ-TuRC-Augmin is protected from degradation during interphase and released in mitosis to aid chromosome alignment. This study provides a unique view on γ-TuRC structure and molecular organization at centrosomes and identifies an important cellular function of centriole-lumenal γ-TuRCs.
詳細: The reference contains no density for the NEDD1/N-GCP/MZT1 grapnel and density for the GRIP2 domains and gamma-tubulins at spokes 5 and 6 was removed
最終 再構成
解像度のタイプ: BY AUTHOR / 解像度: 4.6 Å / 解像度の算出法: FSC 0.143 CUT-OFF / 使用した粒子像数: 299022
初期 角度割当
タイプ: MAXIMUM LIKELIHOOD
最終 角度割当
タイプ: MAXIMUM LIKELIHOOD
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原子モデル構築 1
精密化
空間: REAL / プロトコル: FLEXIBLE FIT
得られたモデル
PDB-9i8n: NEDD1-bound native vertebrate gamma-tubulin ring complex from Xenopus laevis