Paucity of Paucimannosylation Revoked

Paucimannosidic N-glycans (PMGs) are special in that they only have the chitobiose core of two β-linked N-acetylglucosamines extended with up to three mannose residues and a core fucose. While such short-chain glycans are well described in plants, reports on their expression in humans have been rather scarce. Also, these glycans are often seen as a potential analytical artifact. Recently, it became clear that PMGs are abundantly expressed on various proteins from human neutrophils, opening up a new field of research into the potential biological roles of these modifications. Another niche where PMGs have repeatedly been described are human cancer tissues and cell lines. Chatterjee et al. build on these scattered reports by performing a large-scale pan-cancer investigation showing that PMGs are broadly expressed in different types of tumor tissues as well as related cell lines. Also, the related noncancerous control tissues likewise exhibit PMGs, albeit at lower levels than the corresponding tumors. In conclusion, this study establishes PMGs as a widely occurring modification of human proteins, and further studies are needed to elucidate the biosynthesis, function and tissue- as well as protein-associated expression of PMGs.