SPY mediates O-fucose modification of hundreds of proteins and sugar-dependent growth in Arabidopsis_(Part 2: EtHCD)

ABSTRACT: The recent discovery of SPY-catalyzed protein O-fucosylation reveals a novel mechanism for regulating nucleocytoplasmic protein functions in plants. Genetic evidence indicates important roles of SPY in diverse developmental and physiological processes, however, the upstream signal controlling SPY activity and the downstream substrate proteins O-fucosylated by SPY remain largely unknown. Here, we demonstrate that SPY mediates sugar-dependent growth. We further identify hundreds of O-fucosylated proteins using lectin affinity chromatography followed by mass spectrometry. All the O-fucosylation events quantified in proteomic analyses are undetectable or decreased in the spy mutants and thus likely catalyzed by SPY. The O-fucosylome includes mostly nuclear and cytosolic proteins. Many O-fucosylated proteins function in essential cellular processes, hormone signaling, and developmental programs, consistent with the genetic functions of SPY. The O-fucosylome also includes many proteins modified by O-linked-N-acetylglucosamine (O-GlcNAc) and by phosphorylation downstream of the target of rapamycin (TOR) kinase, revealing the convergence of these nutrient signaling pathways on key regulatory functions such as post-transcriptional/translational regulation and hormonal responses. Our study identifies numerous targets of SPY/O-fucosylation and potential nodes of crosstalk among sugar/nutrient signaling pathways, enabling future dissection of the signaling network that mediates sugar regulation of plant growth and development.

INSTRUMENT(S): Orbitrap Eclipse, Q Exactive HF

ORGANISM(S): Arabidopsis Thaliana (mouse-ear Cress)

TISSUE(S): Plant Cell, Seedling

SUBMITTER: Shouling Xu  

LAB HEAD: Shouling Xu

PROVIDER: PXD038491 | Pride | 2023-05-10

REPOSITORIES: Pride