ジャーナル: Nat Struct Mol Biol / 年: 2023 タイトル: The molecular structure of IFT-A and IFT-B in anterograde intraflagellar transport trains. 著者: Samuel E Lacey / Helen E Foster / Gaia Pigino / 要旨: Anterograde intraflagellar transport (IFT) trains are essential for cilia assembly and maintenance. These trains are formed of 22 IFT-A and IFT-B proteins that link structural and signaling cargos to ...Anterograde intraflagellar transport (IFT) trains are essential for cilia assembly and maintenance. These trains are formed of 22 IFT-A and IFT-B proteins that link structural and signaling cargos to microtubule motors for import into cilia. It remains unknown how the IFT-A/-B proteins are arranged into complexes and how these complexes polymerize into functional trains. Here we use in situ cryo-electron tomography of Chlamydomonas reinhardtii cilia and AlphaFold2 protein structure predictions to generate a molecular model of the entire anterograde train. We show how the conformations of both IFT-A and IFT-B are dependent on lateral interactions with neighboring repeats, suggesting that polymerization is required to cooperatively stabilize the complexes. Following three-dimensional classification, we reveal how IFT-B extends two flexible tethers to maintain a connection with IFT-A that can withstand the mechanical stresses present in actively beating cilia. Overall, our findings provide a framework for understanding the fundamental processes that govern cilia assembly.
Masked classification of the periphery of IFTB2 complex, in the region corrresponding to IFT172 (WD domains) and IFT57 CH domain. Lowpass filtered to 18 angstrom and a b factor of -1300 A^2 applied.
全体 : Two IFTB repeats from anterograde intraflagellar transport trains...
全体
名称: Two IFTB repeats from anterograde intraflagellar transport trains within native Chlamydomonas reinhardtii cilia
要素
複合体: Two IFTB repeats from anterograde intraflagellar transport trains within native Chlamydomonas reinhardtii cilia
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超分子 #1: Two IFTB repeats from anterograde intraflagellar transport trains...
超分子
名称: Two IFTB repeats from anterograde intraflagellar transport trains within native Chlamydomonas reinhardtii cilia タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: #1-#13
由来(天然)
生物種: Chlamydomonas reinhardtii (クラミドモナス)
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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
サブトモグラム平均法
試料の集合状態
helical array
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試料調製
緩衝液
pH: 7 / 詳細: TAP (Tris-Acetate-Phosphate) Media
凍結
凍結剤: ETHANE
詳細
Chlamydomonas reinhardtii cells applied to quantifoil grids and plunge frozen; cilia project out from cell bodies and traverse holes in the carbon film.
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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: FEI FALCON IV (4k x 4k) 平均電子線量: 2.6 e/Å2