ジャーナル: Sci Adv / 年: 2020 タイトル: Architecture of the AP2/clathrin coat on the membranes of clathrin-coated vesicles. 著者: Oleksiy Kovtun / Veronica Kane Dickson / Bernard T Kelly / David J Owen / John A G Briggs / 要旨: Clathrin-mediated endocytosis (CME) is crucial for modulating the protein composition of a cell's plasma membrane. Clathrin forms a cage-like, polyhedral outer scaffold around a vesicle, to which ...Clathrin-mediated endocytosis (CME) is crucial for modulating the protein composition of a cell's plasma membrane. Clathrin forms a cage-like, polyhedral outer scaffold around a vesicle, to which cargo-selecting clathrin adaptors are attached. Adaptor protein complex (AP2) is the key adaptor in CME. Crystallography has shown AP2 to adopt a range of conformations. Here, we used cryo-electron microscopy, tomography, and subtomogram averaging to determine structures, interactions, and arrangements of clathrin and AP2 at the key steps of coat assembly, from AP2 in solution to membrane-assembled clathrin-coated vesicles (CCVs). AP2 binds cargo and PtdIns(4,5) (phosphatidylinositol 4,5-bisphosphate)-containing membranes via multiple interfaces, undergoing conformational rearrangement from its cytosolic state. The binding mode of AP2 β2 appendage into the clathrin lattice in CCVs and buds implies how the adaptor structurally modulates coat curvature and coat disassembly.
名称: Clathrin/AP2 coat assembled on membrane. / タイプ: complex / ID: 1 / 親要素: 0 詳細: Clathrin/AP coat was formed on the membrane containing cargo signal peptides. The AP2 adaptor lacked hinge and appendage regions in its alpha subunit.
凍結剤: ETHANE / チャンバー内湿度: 98 % / チャンバー内温度: 291 K / 装置: LEICA EM GP 詳細: The sample was supplemented with 10 nm nanogold fiducials, and 3 ul of the mixture was backside blotted for 3 seconds..
詳細
The sample (in vitro budding reaction) contained AP2, clathrin and 400 nm extruded liposomes
-
電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
特殊光学系
エネルギーフィルター - 名称: GIF Quantum LS / エネルギーフィルター - スリット幅: 20 eV
撮影
フィルム・検出器のモデル: GATAN K2 QUANTUM (4k x 4k) 検出モード: COUNTING / デジタル化 - サイズ - 横: 3838 pixel / デジタル化 - サイズ - 縦: 3710 pixel / デジタル化 - 画像ごとのフレーム数: 1-10 / 撮影したグリッド数: 2 / 平均露光時間: 0.2 sec. / 平均電子線量: 3.2 e/Å2 詳細: The images were collected in movie mode at 10 frames per second
The images were low pass filtered according to the cumulative radiation dose.
最終 再構成
想定した対称性 - 点群: C1 (非対称) / 解像度のタイプ: BY AUTHOR / 解像度: 7.7 Å / 解像度の算出法: FSC 0.143 CUT-OFF / ソフトウェア: (名称: TOM, AV3) / 使用したサブトモグラム数: 24759
抽出
トモグラム数: 58121 / 使用した粒子像数: 198871 / 参照モデル: reference-free / 手法: geometrically defined initial positions / ソフトウェア - 名称: TOM 詳細: To define initial positions of subtomograms, centres and radii of coated vesicles, buds were manually marked in bin4 tomograms. These measurements were used to define spheres. Subtomogram ...詳細: To define initial positions of subtomograms, centres and radii of coated vesicles, buds were manually marked in bin4 tomograms. These measurements were used to define spheres. Subtomogram positions were then defined on the surface of these spheres with uniform sampling. The orientations were calculated to be normal to the surfaces of the spheres with random in-plane rotation.
CTF補正
ソフトウェア - 名称: NOVACTF (ver. 1.0) / 詳細: CTF correction in novaCTF with by multiplication