Browsing by Subject "Fucosyltransferases"

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Structure and dynamics of the Arabidopsis O-fucosyltransferase SPINDLY.
    (Nature communications, 2023-03) Kumar, Shivesh; Wang, Yan; Zhou, Ye; Dillard, Lucas; Li, Fay-Wei; Sciandra, Carly A; Sui, Ning; Zentella, Rodolfo; Zahn, Emily; Shabanowitz, Jeffrey; Hunt, Donald F; Borgnia, Mario J; Bartesaghi, Alberto; Sun, Tai-Ping; Zhou, Pei
    SPINDLY (SPY) in Arabidopsis thaliana is a novel nucleocytoplasmic protein O-fucosyltransferase (POFUT), which regulates diverse developmental processes. Sequence analysis indicates that SPY is distinct from ER-localized POFUTs and contains N-terminal tetratricopeptide repeats (TPRs) and a C-terminal catalytic domain resembling the O-linked-N-acetylglucosamine (GlcNAc) transferases (OGTs). However, the structural feature that determines the distinct enzymatic selectivity of SPY remains unknown. Here we report the cryo-electron microscopy (cryo-EM) structure of SPY and its complex with GDP-fucose, revealing distinct active-site features enabling GDP-fucose instead of UDP-GlcNAc binding. SPY forms an antiparallel dimer instead of the X-shaped dimer in human OGT, and its catalytic domain interconverts among multiple conformations. Analysis of mass spectrometry, co-IP, fucosylation activity, and cryo-EM data further demonstrates that the N-terminal disordered peptide in SPY contains trans auto-fucosylation sites and inhibits the POFUT activity, whereas TPRs 1-5 dynamically regulate SPY activity by interfering with protein substrate binding.
  • Thumbnail Image
    ItemOpen Access
    The Arabidopsis O-fucosyltransferase SPINDLY activates nuclear growth repressor DELLA.
    (Nat Chem Biol, 2017-05) Zentella, Rodolfo; Sui, Ning; Barnhill, Benjamin; Hsieh, Wen-Ping; Hu, Jianhong; Shabanowitz, Jeffrey; Boyce, Michael; Olszewski, Neil E; Zhou, Pei; Hunt, Donald F; Sun, Tai-Ping
    Plant development requires coordination among complex signaling networks to enhance the plant's adaptation to changing environments. DELLAs, transcription regulators originally identified as repressors of phytohormone gibberellin signaling, play a central role in integrating multiple signaling activities via direct protein interactions with key transcription factors. Here, we found that DELLA is mono-O-fucosylated by the novel O-fucosyltransferase SPINDLY (SPY) in Arabidopsis thaliana. O-fucosylation activates DELLA by promoting its interaction with key regulators in brassinosteroid- and light-signaling pathways, including BRASSINAZOLE-RESISTANT1 (BZR1), PHYTOCHROME-INTERACTING-FACTOR3 (PIF3) and PIF4. Moreover, spy mutants displayed elevated responses to gibberellin and brassinosteroid, and increased expression of common target genes of DELLAs, BZR1 and PIFs. Our study revealed that SPY-dependent protein O-fucosylation plays a key role in regulating plant development. This finding may have broader importance because SPY orthologs are conserved in prokaryotes and eukaryotes, thus suggesting that intracellular O-fucosylation may regulate a wide range of biological processes in diverse organisms.