期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2017
卷号：114
期号：33
页码：E6749-E6758
DOI：10.1073/pnas.1702688114
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：O -linked GlcNAcylation ( O -GlcNAcylation), a ubiquitous posttranslational modification on intracellular proteins, is dynamically regulated in cells. To analyze the turnover dynamics of O -GlcNAcylated proteins, we developed a quantitative time-resolved O -linked GlcNAc proteomics (qTOP) strategy based on metabolic pulse-chase labeling with an O -GlcNAc chemical reporter and stable isotope labeling with amino acids in cell culture (SILAC). Applying qTOP, we quantified the turnover rates of 533 O -GlcNAcylated proteins in NIH 3T3 cells and discovered that about 14% exhibited minimal removal of O -GlcNAc or degradation of protein backbones. The stability of those hyperstable O -GlcNAcylated proteins was more sensitive to O -GlcNAcylation inhibition compared with the more dynamic populations. Among the hyperstable population were three core proteins of box C/D small nucleolar ribonucleoprotein complexes (snoRNPs): fibrillarin (FBL), nucleolar protein 5A (NOP56), and nucleolar protein 5 (NOP58). We showed that O -GlcNAcylation stabilized these proteins and was essential for snoRNP assembly. Blocking O -GlcNAcylation on FBL altered the 2′- O -methylation of rRNAs and impaired cancer cell proliferation and tumor formation in vivo.
