Ubiquitination-ralated Genes Is Regulated By O-GlcNAcylation

Intricate cross-talks exist among multiple post-translational modifications thatplay critical roles in various cellular events, such as the control of gene expression andregulation of protein function. Ubiquitination is a multi-step process sequentiallycatalyzed by ubiquitin-activating enzyme (E1), ubiquitin-conjugating enzyme (E2),and ubiquitin-ligase (E3). Some of these enzymes are modified by O-GlcNAc orregulated by protein O-GlcNAcyaltion in transcriptional level. Here the corss-talkbetween O-GlcNAcyaltion and ubiquitination was investigated in HEK293T cells. ByRT2profiler PCR array,84genes related to Human Ubiquitination Pathway wasexplorated in their transcriptional level under augmented protein O-GlcNAcylationlevel evoked by over expression of OGT, inhibition of OGA or over intake of GlcN.An F-Box protein, FBXW10, was down-regulated under all these conditions,suggesting its regulation by proteins O-GlcNAcylation. By RT-PCR and western blotanalysis, it was found that FBXW10could be sharply down-regulated in mRNA andprotein level in GlcN-treated cells in a time dependent way, in line with theenhancement of protein O-GlcNAcylation. It was found that endogenous FBXW10was modified by O-GlcNAc in HEK293T cells, implying O-GlcNAcylation mightregulate FBXW10in multiple levels. These findings indicate that proteinO-GlcNAcylation is involved in regulation of ubiquitination pathway related genes,and help us understand the cross-talk between O-GlcNAcylation and ubiquitination.