J Integr Plant Biol. ›› 2023, Vol. 65 ›› Issue (9): 2086-2106.DOI: 10.1111/jipb.13540

• Cell and Developmental Biology • Previous Articles     Next Articles

Regulation of FLC nuclear import by coordinated action of the NUP62-subcomplex and importin β SAD2

Gang Chen, Danyun Xu, Qing Liu, Zhichuang Yue, Biao Dai, Shujuan Pan, Yongqiang Chen, Xinhua Feng and Honghong Hu*   

  1. National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China
    These authors contributed equally to this work.
    *Correspondence: Honghong Hu (huhh@mail.hzau.edu.cn)
  • Received:2023-05-27 Accepted:2023-06-05 Online:2023-06-06 Published:2023-09-01

Abstract: Flowering locus C (FLC) is a central transcriptional repressor that controls flowering time. However, how FLC is imported into the nucleus is unknown. Here, we report that Arabidopsis nucleoporins 62 (NUP62), NUP58, and NUP54 composed NUP62-subcomplex modulates FLC nuclear import during floral transition in an importin α-independent manner, via direct interaction. NUP62 recruits FLC to the cytoplasmic filaments and imports it into the nucleus through the NUP62-subcomplex composed central channel. Importin β supersensitive to ABA and drought 2 (SAD2), a carrier protein, is critical for FLC nuclear import and flower transition, which facilitates FLC import into the nucleus mainly through the NUP62-subcomplex. Proteomics, RNA-seq, and cell biological analyses indicate that the NUP62-subcomplex mainly mediates the nuclear import of cargos with unconventional nuclear localization sequences (NLSs), such as FLC. Our findings illustrate the mechanisms of the NUP62-subcomplex and SAD2 on FLC nuclear import process and floral transition, and provide insights into the role of NUP62-subcomplex and SAD2 in protein nucleocytoplasmic transport in plants.

Key words: FLC, flowering time, importin, nuclear import, nucleoporin

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