ジャーナル: J Mol Biol / 年: 2016 タイトル: The Structural Basis of Actin Organization by Vinculin and Metavinculin. 著者: Laura Y Kim / Peter M Thompson / Hyunna T Lee / Mihir Pershad / Sharon L Campbell / Gregory M Alushin / 要旨: Vinculin is an essential adhesion protein that links membrane-bound integrin and cadherin receptors through their intracellular binding partners to filamentous actin, facilitating mechanotransduction. ...Vinculin is an essential adhesion protein that links membrane-bound integrin and cadherin receptors through their intracellular binding partners to filamentous actin, facilitating mechanotransduction. Here we present an 8.5-Å-resolution cryo-electron microscopy reconstruction and pseudo-atomic model of the vinculin tail (Vt) domain bound to F-actin. Upon actin engagement, the N-terminal "strap" and helix 1 are displaced from the Vt helical bundle to mediate actin bundling. We find that an analogous conformational change also occurs in the H1' helix of the tail domain of metavinculin (MVt) upon actin binding, a muscle-specific splice isoform that suppresses actin bundling by Vt. These data support a model in which metavinculin tunes the actin bundling activity of vinculin in a tissue-specific manner, providing a mechanistic framework for understanding metavinculin mutations associated with hereditary cardiomyopathies.
名称: 50 mM KCl, 1 mM MgCl2, 1 mM EGTA, 10 mM imidazole / pH: 7 / 詳細: 50 mM KCl, 1 mM MgCl2, 1 mM EGTA, 10 mM imidazole
試料
濃度: 0.0125 mg/ml / 包埋: NO / シャドウイング: NO / 染色: NO / 凍結: YES
試料支持
詳細: 200 mesh 1.2 / 1.3 C-flat
急速凍結
装置: LEICA EM GP / 凍結剤: ETHANE / 湿度: 90 % 詳細: 3 microliters of 0.3 micromolar actin was applied to the grid and incubated for 60 seconds at 25 degrees C. 3 microliters of 10 micromolar MVt was then applied and incubated for 60 seconds. 3 ...詳細: 3 microliters of 0.3 micromolar actin was applied to the grid and incubated for 60 seconds at 25 degrees C. 3 microliters of 10 micromolar MVt was then applied and incubated for 60 seconds. 3 microliters of solution was removed, then an additional 3 microliters of MVt applied. After 60 seconds, 3 microliters of solution was removed, then the grid was blotted for 2 seconds before plunging into liquid ethane (LEICA EM GP). 手法: 3 microliters of 0.3 micromolar actin was applied to the grid and incubated for 60 seconds at 25 degrees C. 3 microliters of 10 micromolar MVt was then applied and incubated for 60 seconds. 3 ...手法: 3 microliters of 0.3 micromolar actin was applied to the grid and incubated for 60 seconds at 25 degrees C. 3 microliters of 10 micromolar MVt was then applied and incubated for 60 seconds. 3 microliters of solution was removed, then an additional 3 microliters of MVt applied. After 60 seconds, 3 microliters of solution was removed, then the grid was blotted for 2 seconds before plunging.
モード: BRIGHT FIELD / 倍率(公称値): 100000 X / 倍率(補正後): 137615 X / 最大 デフォーカス(公称値): 3000 nm / 最小 デフォーカス(公称値): 1500 nm / Cs: 2 mm 非点収差: Objective lens astigmatism was corrected at 100,000 times magnification.
試料ホルダ
試料ホルダーモデル: GATAN LIQUID NITROGEN
撮影
電子線照射量: 25 e/Å2 フィルム・検出器のモデル: GATAN ULTRASCAN 4000 (4k x 4k)
画像スキャン
デジタル画像の数: 671
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解析
EMソフトウェア
ID
名称
バージョン
カテゴリ
1
CTFFIND
3
CTF補正
2
MDFF
モデルフィッティング
3
UCSF Chimera
モデルフィッティング
4
EMAN
2
3次元再構成
5
FREALIGN
3次元再構成
6
SPARX
3次元再構成
CTF補正
詳細: FREALIGN (per segment)
らせん対称
回転角度/サブユニット: 166.75 ° / 軸方向距離/サブユニット: 27.8 Å / らせん対称軸の対称性: C1
3次元再構成
手法: IHRSR / 解像度: 8.2 Å / 解像度の算出法: FSC 0.143 CUT-OFF / ピクセルサイズ(公称値): 2.18 Å / ピクセルサイズ(実測値): 2.18 Å 詳細: (Helical Details: Multi-model IHRSR was performed using EMAN2 / SPARX to select for bound segments, followed by single model IHRSR with EMAN2 / SPARX and final reconstruction with FREALIGN ...詳細: (Helical Details: Multi-model IHRSR was performed using EMAN2 / SPARX to select for bound segments, followed by single model IHRSR with EMAN2 / SPARX and final reconstruction with FREALIGN (fixed helical parameters).) 対称性のタイプ: HELICAL
原子モデル構築
ID
プロトコル
空間
詳細
1
FLEXIBLEFIT
REAL
REFINEMENT PROTOCOL--flexible DETAILS--Components were initially rigid body fit using Chimera, followed by flexible fitting with MDFF.
2
FLEXIBLEFIT
REAL
REFINEMENT PROTOCOL--flexible DETAILS--Components were initially rigid body fit using Chimera, followed by flexible fitting with MDFF.
原子モデル構築
PDB chain-ID: A / Source name: PDB / タイプ: experimental model