O-GlcNAcylation, an original modulator of contractile activity in striated muscle

There is growing evidence that O-linked N-acetyl-D-glucosaminylation, more simply termed O-GlcNAcylation or O-GlcNAc, is a post-translational modification involved in many cellular processes from transcription to modulation of protein properties. O-GlcNAc is a dynamic and reversible glycosylation and therefore quite similar to the phosphorylation/dephosphorylation process, with which O-GlcNAc can interplay. Since O-GlcNAc serves as a glucose sensor by the way of hexosamine biosynthesis pathway, this glycosylation is often associated with glucose toxicity and development of insulin resistance. In this way, O-GlcNAc could be involved in muscle pathological consequences of diabetes. Nevertheless, in regards of several studies performed in healthy striated muscles, O-GlcNAc seems to exert protective effects against different types of injuries. Recent new insights suggest a key implication of O-GlcNAc in skeletal and cardiac muscles contractile activity, in particular by O-GlcNAc modification of motor as well as regulating contractile proteins. While evidence linked O-GlcNAc to the regulation of calcium activation properties, its exact role remains to be defined as well as the existence of potential interference with phosphorylation. The better understanding of the exact function of OGlcNAc in this physiological process could contribute to the determination of newly markers of skeletal dysfunctions.