ジャーナル: Proc Natl Acad Sci U S A / 年: 2023 タイトル: In situ snapshots along a mammalian selective autophagy pathway. 著者: Meijing Li / Ishita Tripathi-Giesgen / Brenda A Schulman / Wolfgang Baumeister / Florian Wilfling / 要旨: Selective macroautophagy (hereafter referred to as autophagy) describes a process in which cytosolic material is engulfed in a double membrane organelle called an autophagosome. Autophagosomes are ...Selective macroautophagy (hereafter referred to as autophagy) describes a process in which cytosolic material is engulfed in a double membrane organelle called an autophagosome. Autophagosomes are carriers responsible for delivering their content to a lytic compartment for destruction. The cargo can be of diverse origin, ranging from macromolecular complexes to protein aggregates, organelles, and even invading pathogens. Each cargo is unique in composition and size, presenting different challenges to autophagosome biogenesis. Among the largest cargoes targeted by the autophagy machinery are intracellular bacteria, which can, in the case of range from 2 to 5 μm in length and 0.5 to 1.5 μm in width. How phagophores form and expand on such a large cargo remains mechanistically unclear. Here, we used HeLa cells infected with an auxotrophic to study the process of phagophore biogenesis using in situ correlative cryo-ET. We show that host cells generate multiple phagophores at the site of damaged -containing vacuoles (SCVs). The observed double membrane structures range from disk-shaped to expanded cup-shaped phagophores, which have a thin intermembrane lumen with a dilating rim region and expand using the SCV, the outer membrane of , or existing phagophores as templates. Phagophore rims establish different forms of contact with the endoplasmic reticulum (ER) via structurally distinct molecular entities for membrane formation and expansion. Early omegasomes correlated with the marker Double-FYVE domain-Containing Protein 1 (DFCP1) are observed in close association with the ER without apparent membrane continuity. Our study provides insights into the formation of phagophores around one of the largest selective cargoes.
A: 6644.48 Å / B: 6644.48 Å / C: 2047.76 Å α=β=γ: 90.0 °
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添付データ
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試料の構成要素
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全体 : HeLa cells infected with Salmonella
全体
名称: HeLa cells infected with Salmonella
要素
細胞: HeLa cells infected with Salmonella
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超分子 #1: HeLa cells infected with Salmonella
超分子
名称: HeLa cells infected with Salmonella / タイプ: cell / ID: 1 / 親要素: 0
由来(天然)
生物種: Homo sapiens (ヒト)
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実験情報
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構造解析
手法
クライオ電子顕微鏡法
解析
電子線トモグラフィー法
試料の集合状態
cell
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試料調製
緩衝液
pH: 7
凍結
凍結剤: ETHANE-PROPANE
Cryo protectant
10% Glycerol
切片作成
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 kV / 集束イオンビーム - 電流: 15 nA / 集束イオンビーム - 時間: 20 sec. / 集束イオンビーム - 温度: 91 K / 集束イオンビーム - Initial thickness: 1000 nm / 集束イオンビーム - 最終 厚さ: 150 nm 集束イオンビーム - 詳細: The value given for _em_focused_ion_beam.instrument is FEI Aquilos FIB. 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: 120.0 e/Å2