National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R01-GM07391
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
T32-GM008275
米国
National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
F31-HL146077
米国
引用
ジャーナル: Nat Commun / 年: 2022 タイトル: Molecular mechanism of Arp2/3 complex inhibition by Arpin. 著者: Fred E Fregoso / Trevor van Eeuwen / Gleb Simanov / Grzegorz Rebowski / Malgorzata Boczkowska / Austin Zimmet / Alexis M Gautreau / Roberto Dominguez / 要旨: Positive feedback loops involving signaling and actin assembly factors mediate the formation and remodeling of branched actin networks in processes ranging from cell and organelle motility to ...Positive feedback loops involving signaling and actin assembly factors mediate the formation and remodeling of branched actin networks in processes ranging from cell and organelle motility to mechanosensation. The Arp2/3 complex inhibitor Arpin controls the directional persistence of cell migration by interrupting a feedback loop involving Rac-WAVE-Arp2/3 complex, but Arpin's mechanism of inhibition is unknown. Here, we describe the cryo-EM structure of Arpin bound to Arp2/3 complex at 3.24-Å resolution. Unexpectedly, Arpin binds Arp2/3 complex similarly to WASP-family nucleation-promoting factors (NPFs) that activate the complex. However, whereas NPFs bind to two sites on Arp2/3 complex, on Arp2-ArpC1 and Arp3, Arpin only binds to the site on Arp3. Like NPFs, Arpin has a C-helix that binds at the barbed end of Arp3. Mutagenesis studies in vitro and in cells reveal how sequence differences within the C-helix define the molecular basis for inhibition by Arpin vs. activation by NPFs.
濃度: 5 mg/ml / 包埋: NO / シャドウイング: NO / 染色: NO / 凍結: YES / 詳細: This sample was monodisperse.
試料支持
詳細: unspecified
急速凍結
装置: LEICA EM CPC / 凍結剤: ETHANE 詳細: Grids were manually blotted for 3 seconds with Whatman 41 filter paper and manually plunged using a Leica EM CPC manual plunger.
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電子顕微鏡撮影
実験機器
モデル: Titan Krios / 画像提供: FEI Company
顕微鏡
モデル: FEI TITAN KRIOS 詳細: Data were collected in super-resolution mode with an illuminated area of 1.01 um, nominal dose of 40 e-/A^2, a dose rate of 4.87 e-/s/pixel, and 2 or 5 exposures per hole by image shift.
詳細: Super resolution mode; micrographs binned during motion correction
CTF補正
詳細: CTF correction was done in cryoSPARC for intial 2D classification and then repeated in CTFFIND4 (Relion) for classification and final reconstruction. タイプ: PHASE FLIPPING AND AMPLITUDE CORRECTION
粒子像の選択
選択した粒子像数: 4485066 / 詳細: Particles autopicked in cryoSPARC
対称性
点対称性: C1 (非対称)
3次元再構成
解像度: 3.24 Å / 解像度の算出法: FSC 0.143 CUT-OFF / 粒子像の数: 182324 / アルゴリズム: FOURIER SPACE / クラス平均像の数: 1 / 対称性のタイプ: POINT
原子モデル構築
B value: 132 / プロトコル: FLEXIBLE FIT / 空間: REAL / Target criteria: correlation