O-Linked β-
N-acetylglucosamine-modification (
O-GlcNAcylation) is a reversible, post-translational, and regulatory modification of nuclear, mitochondrial, and cytoplasmic proteins that is responsive to cellular stress. However, the role of
O-GlcNAcylation in the induction of heat shock proteins (Hsps) by arsenite remains unclear. We used
O-(2-acetamido-2-deoxy-D-glucopyranosylidene) amino
N-phenyl carbamate (PUGNAc), an inhibitor of
O-GlcNAcase, and glucosamine (GlcN), an enhancer of the hexosamine biosynthesis pathway, or
O-GlcNAc transferase (OGT) short interfering RNA (siRNA) to enhance or suppress cellular
O-GlcNAcylation levels, respectively, in HeLa cells. The exposure to arsenite increased
O-GlcNAcylation and Hsp 70 levels in HeLa cells. However, the pre-treatment with PUGNAc or GlcN, which enhanced
O-GlcNAcylation levels, decreased the arsenite-induced expression of Hsp 70. The pre-treatment with OGT siRNA, which suppressed
O-GlcNAcylation levels, did not affect the induction of Hsp 70. We then examined the effects of
O-GlcNAcylation on the nuclear translocation and phosphorylation of heat shock factor 1 (HSF1), and found that neither the nuclear translocation nor phosphorylation of HSF1 was regulated by
O-GlcNAcylation. Finally,
Hsp 70 mRNA expression was induced by arsenite, whereas the addition of PUGNAc slightly suppressed its induction. These results indicate that
O-GlcNAcylation is related to arsenite-induced Hsp 70 expression, and demonstrated that hyper-
O-GlcNAcylation inhibited the induction of Hsp 70
via transcriptional factors instead of HSF1.
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