Ischemic preconditioning increases myocardial O-GlcNAc glycosylation.

Objectives: Through the hexosamine biosynthetic pathway (HBP) proteins are modified by O-linked-β-N-acetylglucosamine (O-GlcNAc), which acts as a stress sensor. Augmentation of O-GlcNAc confers cardioprotection against ischemia- reperfusion injury, but its role in ischemic preconditioning (IPC) is unknown. Azaserine and alloxan are unspecific blockers of the HBP and have been used to block the cardioprotective effects of O-GlcNAc.

Nucleocytoplasmic glycosylation, O-GlcNAc: identification and site mapping.

beta-O-linked N-acetylglucosamine (O-GlcNAc) is posttranslationally added to serine and threonine residues of many nuclear and cytoplasmic proteins found in metazoans. This modification is dynamic and responsive to numerous stimuli and conditions, suggesting an important role in many regulatory pathways. Moreover, the O-GlcNAc modification seems to compete with phosphorylation for sites of attachment, indicating a reciprocal relationship with phosphorylation.