National Institutes of Health/Office of the Director
DP5 OD021396-01
米国
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)
AI064326
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM071862
米国
National Institutes of Health/National Cancer Institute (NIH/NCI)
CA141722
米国
引用
ジャーナル: Cell Rep / 年: 2016 タイトル: Structural Basis for the Activation of IKK1/α. 著者: Smarajit Polley / Dario Oliveira Passos / De-Bin Huang / Maria Carmen Mulero / Anup Mazumder / Tapan Biswas / Inder M Verma / Dmitry Lyumkis / Gourisankar Ghosh / 要旨: Distinct signaling pathways activate the NF-κB family of transcription factors. The canonical NF-κB-signaling pathway is mediated by IκB kinase 2/β (IKK2/β), while the non-canonical pathway ...Distinct signaling pathways activate the NF-κB family of transcription factors. The canonical NF-κB-signaling pathway is mediated by IκB kinase 2/β (IKK2/β), while the non-canonical pathway depends on IKK1/α. The structural and biochemical bases for distinct signaling by these otherwise highly similar IKKs are unclear. We report single-particle cryoelectron microscopy (cryo-EM) and X-ray crystal structures of human IKK1 in dimeric (∼150 kDa) and hexameric (∼450 kDa) forms. The hexamer, which is the representative form in the crystal but comprises only ∼2% of the particles in solution by cryo-EM, is a trimer of IKK1 dimers. While IKK1 hexamers are not detectable in cells, the surface that supports hexamer formation is critical for IKK1-dependent cellular processing of p100 to p52, the hallmark of non-canonical NF-κB signaling. Comparison of this surface to that in IKK2 indicates significant divergence, and it suggests a fundamental role for this surface in signaling by these kinases through distinct pathways.
凍結剤: ETHANE / チャンバー内湿度: 80 % / チャンバー内温度: 277 K / 装置: HOMEMADE PLUNGER 詳細: Sample containing IKK1 dimers in SEC buffer was applied onto freshly plasma-treated (6 seconds, Gatan Solarus plasma cleaner) holey carbon C-flat grids (Protochips), adsorbed for 30 seconds, ...詳細: Sample containing IKK1 dimers in SEC buffer was applied onto freshly plasma-treated (6 seconds, Gatan Solarus plasma cleaner) holey carbon C-flat grids (Protochips), adsorbed for 30 seconds, and then plunged into liquid ethane using a manual cryo-plunger in an ambient environment of 4 degrees C..
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
温度
最低: 70.0 K / 最高: 70.0 K
撮影
フィルム・検出器のモデル: GATAN K2 SUMMIT (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 - サンプリング間隔: 5.0 µm / デジタル化 - 画像ごとのフレーム数: 1-50 / 撮影したグリッド数: 1 / 実像数: 2918 / 平均露光時間: 10.0 sec. / 平均電子線量: 40.0 e/Å2 詳細: The dose was fractionated over 50 raw frames collected over a 10 second exposure time (200 ms per frame) on the Gatan K2 Summit direct detection device, with each frame receiving a dose of ~6. ...詳細: The dose was fractionated over 50 raw frames collected over a 10 second exposure time (200 ms per frame) on the Gatan K2 Summit direct detection device, with each frame receiving a dose of ~6.5 e-/pixel/sec. 2918 movies were collected and recorded at a nominal magnification of 22,500, corresponding to a pixel size of 1.31 A at the specimen level. The individual frames were gain-corrected, then aligned and summed using a GPU-enabled whole frame alignment program (Li et al., 2013), and exposure-filtered (Grant and Grigorieff, 2015).
ソフトウェア - 名称: FREALIGN (ver. 9.11) 詳細: During 2D alignment and classification, we noticed that a small percentage of particles apparently formed multiple dimers stacked side-by-side. After several rounds of sub-classification, it ...詳細: During 2D alignment and classification, we noticed that a small percentage of particles apparently formed multiple dimers stacked side-by-side. After several rounds of sub-classification, it became apparent that this small percentage of particles actually corresponded to an oligomer of IKK1 dimers. An ab initio initial model was generated from the subset of particles using OptiMod, which showed that the oligomer was clearly hexameric in nature. 3D classifications and refinements were performed in a similar fashion as for the dimers. Only one conformational state was identified (despite asking for the recovery of up to 5 classes), which was refined to ~5.9 A resolution