TY - JOUR TI - Importin-9 wraps around the H2A-H2B core to act as nuclear importer and histone chaperone AU - Padavannil, Abhilash AU - Sarkar, Prithwijit AU - Kim, Seung Joong AU - Cagatay, Tolga AU - Jiou, Jenny AU - Brautigam, Chad A AU - Tomchick, Diana R AU - Sali, Andrej AU - D'Arcy, Sheena AU - Chook, Yuh Min A2 - Musacchio, Andrea A2 - Weigel, Detlef VL - 8 PY - 2019 DA - 2019/03/11 SP - e43630 C1 - eLife 2019;8:e43630 DO - 10.7554/eLife.43630 UR - https://doi.org/10.7554/eLife.43630 AB - We report the crystal structure of nuclear import receptor Importin-9 bound to its cargo, the histones H2A-H2B. Importin-9 wraps around the core, globular region of H2A-H2B to form an extensive interface. The nature of this interface coupled with quantitative analysis of deletion mutants of H2A-H2B suggests that the NLS-like sequences in the H2A-H2B tails play a minor role in import. Importin-9•H2A-H2B is reminiscent of interactions between histones and histone chaperones in that it precludes H2A-H2B interactions with DNA and H3-H4 as seen in the nucleosome. Like many histone chaperones, which prevent inappropriate non-nucleosomal interactions, Importin-9 also sequesters H2A-H2B from DNA. Importin-9 appears to act as a storage chaperone for H2A-H2B while escorting it to the nucleus. Surprisingly, RanGTP does not dissociate Importin-9•H2A-H2B but assembles into a RanGTP•Importin-9•H2A-H2B complex. The presence of Ran in the complex, however, modulates Imp9-H2A-H2B interactions to facilitate its dissociation by DNA and assembly into a nucleosome. KW - Importin-9 KW - karyopherin KW - histone KW - H2A-H2B, Ran KW - nucleosome KW - histone chaperone JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -