The role of GlcNAc in formation and function of extracellular matrices

N-acetylglucosamine (GlcNAc) is an abundant hexose that as a monomer or as part of macromolecules plays multiple roles in eukaryotic cells. Especially as a residue of oligo- and polysaccharides and conjugated with lipids and proteins, GlcNAc contributes to the function and architecture of extracellular matrices. Several human disorders caused by mutations in genes coding for enzymes dealing with GlcNAc have been identified. However, molecular aspects of their clinical picture are laborious to investigate and are mostly addressed in yeast and vertebrate cultured cells that as unicellular or artificial systems ultimately do not allow conclusive deductions for complex organisms. An excellent model system to study the biology of GlcNAc in a multi-cellular organism is the genetically, biochemically and physiologically manipulable fruitfly Drosophila melanogaster that despite the evolutionary distance shares basic features of GlcNAc biology with humans. The aim of this review is to summarise the use of GlcNAc both in mammals and in Drosophila by highlighting the molecular consequences of perturbing GlcNAc function.