ジャーナル: EMBO J / 年: 2021 タイトル: Cryo-EM structure of metazoan TRAPPIII, the multi-subunit complex that activates the GTPase Rab1. 著者: Antonio Galindo / Vicente J Planelles-Herrero / Gianluca Degliesposti / Sean Munro / 要旨: The TRAPP complexes are nucleotide exchange factors that play essential roles in membrane traffic and autophagy. TRAPPII activates Rab11, and TRAPPIII activates Rab1, with the two complexes sharing a ...The TRAPP complexes are nucleotide exchange factors that play essential roles in membrane traffic and autophagy. TRAPPII activates Rab11, and TRAPPIII activates Rab1, with the two complexes sharing a core of small subunits that affect nucleotide exchange but being distinguished by specific large subunits that are essential for activity in vivo. Crystal structures of core subunits have revealed the mechanism of Rab activation, but how the core and the large subunits assemble to form the complexes is unknown. We report a cryo-EM structure of the entire Drosophila TRAPPIII complex. The TRAPPIII-specific subunits TRAPPC8 and TRAPPC11 hold the catalytic core like a pair of tongs, with TRAPPC12 and TRAPPC13 positioned at the joint between them. TRAPPC2 and TRAPPC2L link the core to the two large arms, with the interfaces containing residues affected by disease-causing mutations. The TRAPPC8 arm is positioned such that it would contact Rab1 that is bound to the core, indicating how the arm could determine the specificity of the complex. A lower resolution structure of TRAPPII shows a similar architecture and suggests that the TRAPP complexes evolved from a single ur-TRAPP.
凍結剤: ETHANE / チャンバー内湿度: 100 % / チャンバー内温度: 285.15 K / 装置: FEI VITROBOT MARK III
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電子顕微鏡法
顕微鏡
TFS KRIOS
詳細
32% of the images were acquiring tilted the stage 19 degrees.
撮影
フィルム・検出器のモデル: FEI FALCON III (4k x 4k) 検出モード: COUNTING / 撮影したグリッド数: 4 / 実像数: 3671 / 平均露光時間: 0.8 sec. / 平均電子線量: 30.0 e/Å2 詳細: 1190 from the whole dataset were collected with the stage tilted at 19 degrees