ジャーナル: Cell / 年: 2012 タイトル: EBs recognize a nucleotide-dependent structural cap at growing microtubule ends. 著者: Sebastian P Maurer / Franck J Fourniol / Gergő Bohner / Carolyn A Moores / Thomas Surrey / 要旨: Growing microtubule ends serve as transient binding platforms for essential proteins that regulate microtubule dynamics and their interactions with cellular substructures. End-binding proteins (EBs) ...Growing microtubule ends serve as transient binding platforms for essential proteins that regulate microtubule dynamics and their interactions with cellular substructures. End-binding proteins (EBs) autonomously recognize an extended region at growing microtubule ends with unknown structural characteristics and then recruit other factors to the dynamic end structure. Using cryo-electron microscopy, subnanometer single-particle reconstruction, and fluorescence imaging, we present a pseudoatomic model of how the calponin homology (CH) domain of the fission yeast EB Mal3 binds to the end regions of growing microtubules. The Mal3 CH domain bridges protofilaments except at the microtubule seam. By binding close to the exchangeable GTP-binding site, the CH domain is ideally positioned to sense the microtubule's nucleotide state. The same microtubule-end region is also a stabilizing structural cap protecting the microtubule from depolymerization. This insight supports a common structural link between two important biological phenomena, microtubule dynamic instability and end tracking.
アルゴリズム: OTHER / 解像度のタイプ: BY AUTHOR / 解像度: 8.6 Å / 解像度の算出法: FSC 0.5 CUT-OFF / ソフトウェア - 名称: SPIDER, FREALIGN 詳細: approximately 129000 tubulin dimers were averaged together in the final map 使用した粒子像数: 129000
Protocol: Rigid body. Each tubulin monomer and a homology model for Mal3 CH domain were separately fitted using automatic fitting, and the multi-subunit fitting was refined in Flex-EM
精密化
空間: REAL / プロトコル: RIGID BODY FIT / 当てはまり具合の基準: cross-correlation
得られたモデル
PDB-4abo: Mal3 CH domain homology model and mammalian tubulin (2XRP) docked into the 8.6-Angstrom cryo-EM map of Mal3-GTPgammaS-microtubules