National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R35GM141461
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R01GM069909
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
T32GM008203
米国
Welch Foundation
I-1532
米国
Cancer Prevention and Research Institute of Texas (CPRIT)
RP220582
米国
引用
ジャーナル: J Cell Biol / 年: 2025 タイトル: Nap1 and Kap114 co-chaperone H2A-H2B and facilitate targeted histone release in the nucleus. 著者: Ho Yee Joyce Fung / Jenny Jiou / Ashley B Niesman / Natalia E Bernardes / Yuh Min Chook / 要旨: Core histones, synthesized and processed in the cytoplasm, must be chaperoned as they are transported into the nucleus for nucleosome assembly. The importin Kap114 transports H2A-H2B into the yeast ...Core histones, synthesized and processed in the cytoplasm, must be chaperoned as they are transported into the nucleus for nucleosome assembly. The importin Kap114 transports H2A-H2B into the yeast nucleus, where RanGTP facilitates histone release. Kap114 and H2A-H2B also bind the histone chaperone Nap1, but how Nap1 and Kap114 cooperate in transport and nucleosome assembly remains unclear. Here, biochemical and structural analyses show that Kap114, H2A-H2B, and a Nap1 dimer (Nap12) associate in the absence and presence of RanGTP to form equimolar complexes. A previous study had shown that RanGTP reduces Kap114's ability to chaperone H2A-H2B, but a new cryo-EM structure of the Nap12•H2A-H2B•Kap114•RanGTP complex explains how both Kap114 and Nap12 interact with H2A-H2B, restoring its chaperoning within the assembly while effectively depositing it into nucleosomes. Together, our results suggest that Kap114 and Nap12 provide a sheltered path that facilitates the transfer of H2A-H2B from Kap114 to Nap12, ultimately directing its specific deposition into nucleosomes.
全体 : Crosslinked mixture of Kap114 with Nap1 and H2A-H2B
全体
名称: Crosslinked mixture of Kap114 with Nap1 and H2A-H2B
要素
複合体: Crosslinked mixture of Kap114 with Nap1 and H2A-H2B
タンパク質・ペプチド: Yeast Nap1
タンパク質・ペプチド: Histone H2A
タンパク質・ペプチド: Histone H2B
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超分子 #1: Crosslinked mixture of Kap114 with Nap1 and H2A-H2B
超分子
名称: Crosslinked mixture of Kap114 with Nap1 and H2A-H2B / タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: all 詳細: Nap1 and H2A-H2B were pre-complexed with excess histones, and Kap114 was added before mild crosslinking and SEC separation.
選択した数: 4314112 詳細: Blob picking on 100 micrographs and then further template picking.
初期モデル
モデルのタイプ: NONE / 詳細: Ab-initio reconstruction.
最終 再構成
解像度のタイプ: BY AUTHOR / 解像度: 5.62 Å / 解像度の算出法: FSC 0.143 CUT-OFF / ソフトウェア - 名称: cryoSPARC 詳細: Particle subtraction was performed with mask covering part of Kap114, and local refinement was performed over map regions covering Nap1 and H2A-H2B. 使用した粒子像数: 113011