ジャーナル: Cell / 年: 2026 タイトル: Metabolically regulated proteasome supramolecular organization in situ. 著者: Xiaomeng Tang / Lu Qu / Florian Wilfling / Florian Beck / Oliver P Ernst / Brenda A Schulman / Wolfgang Baumeister / Cordula Enenkel / 要旨: Many proteins localize in membraneless organelles. However, understanding the steps along membraneless organelle formation-and the structural impact on granule constituents-has been hindered by ...Many proteins localize in membraneless organelles. However, understanding the steps along membraneless organelle formation-and the structural impact on granule constituents-has been hindered by limited resolution of intracellular data. We address these challenges through in situ cryo-electron tomography (cryo-ET) along with formation of yeast proteasome storage granules (PSGs). During the transition from proliferation to quiescence, doubly capped 26S proteasomes arrested in an inactive state arrange into ∼7.5 MDa trimeric units, dispersed in the nucleoplasm and congregated along the nuclear envelope near the nuclear pore. 9-Å-resolution cryo-ET structures reveal that cytoplasmic PSGs formed in various energy-limiting conditions are paracrystalline arrays of bundled fibers, assembled from stacking of proteasome trimers. The paracrystalline arrangement maintains a pool of fully assembled inactive 26S proteasomes that are released in energy-rich conditions. Overall, our data reveal structural steps along the assembly of an intracellular membraneless organelle in situ and quinary structure formation controlling a major eukaryotic regulatory machine.
集束イオンビーム - 装置: OTHER / 集束イオンビーム - イオン: OTHER / 集束イオンビーム - 電圧: 30 / 集束イオンビーム - 電流: 0.1 / 集束イオンビーム - 時間: 5 / 集束イオンビーム - 温度: 100 K / 集束イオンビーム - Initial thickness: 500 / 集束イオンビーム - 最終 厚さ: 150 集束イオンビーム - 詳細: The value given for _em_focused_ion_beam.instrument is FEI Aquilos. This is not in a list of allowed values {'OTHER', 'DB235'} so OTHER is written into the XML file.
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電子顕微鏡法
顕微鏡
TFS KRIOS
撮影
フィルム・検出器のモデル: GATAN K2 SUMMIT (4k x 4k) 平均電子線量: 2.7 e/Å2
電子線
加速電圧: 300 kV / 電子線源: FIELD EMISSION GUN
電子光学系
照射モード: OTHER / 撮影モード: BRIGHT FIELD / 最大 デフォーカス(公称値): 4.0 µm / 最小 デフォーカス(公称値): 3.0 µm