Chemoproteomic profiling of O-GlcNAcylated proteins and identification of O-GlcNAc transferases in rice

ABSTRACT: O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) is a ubiquitous posttranslational modification occurring in both animals and plants. Thousands of proteins along with their O-GlcNAcylation sites have been identified in various animal systems, yet the O-GlcNAcylated proteomes in plants remain poorly understood. Here, we report a large-scale profiling of protein O-GlcNAcylation in a site-specific manner in rice. We first established the metabolic glycan labeling strategy (MGL) with N-azidoacetylgalactosamine (GalNAz) in rice seedlings, which enabled incorporation of azides as a bioorthogonal handle into O-GlcNAc. By conjugation of the azide-incorporated O-GlcNAc with alkyne-biotin containing a cleavable linker via click chemistry, O-GlcNAcylated proteins were selectively enriched for mass spectrometry (MS) analysis. A total of 1,591 unambiguous O-GlcNAcylation sites distributed on 709 O-GlcNAcylated proteins were identified. Additionally, 102 O-GlcNAcylated proteins were identified with their O-GlcNAcylation sites located within a serine/threonine-enriched peptide, causing ambiguous site assignment. The identified O-GlcNAcylated proteins are involved in multiple biological processes such as transcription, translation and plant hormone signaling. Furthermore, we discovered two O-GlcNAc transferases (OsOGTs) in rice. By expressing OsOGTs in Escherichia coli and Nicotiana benthamiana leaves, we confirmed their OGT enzymatic activities and used them to validate the identified rice O-GlcNAcylated proteins. Our dataset provides a valuable resource for studying O-GlcNAc biology in rice, and the MGL method should facilitate the identification of O-GlcNAcylated proteins in various plants.

INSTRUMENT(S): Orbitrap Fusion Lumos, LTQ Orbitrap Elite

ORGANISM(S): Oryza Sativa (rice)

TISSUE(S): Root, Leaf

SUBMITTER: Cong Lei  

LAB HEAD: Jiayang Li

PROVIDER: PXD036527 | Pride | 2023-05-10

REPOSITORIES: Pride