Introduction to “Glycometabolome”

Abstract

N-glycosylation is now recognized as one of the most important modiˆcation reactions in eukaryotic cells, and it has been demonstrated that N-glycans on glycoproteins have crucial roles on their physicochemical properties such as solubility or stability of proteins, as well as their physiological properties such as bioactivity or intra-and intercellular tra‹cking. Explosive progress of glycobiology during the past decades unveiled most, if not all, of the biosynthetic pathway for N-glycans. On the other hand, how the N-glycans are catabolized in cells is relatively unexplored even in this``post-genome'' era. Here I would like to outline what is known and what should be clariˆed regarding the catabolic pathway of Nglycans.

Free Oligosaccharides to Monitor Glycoprotein Endoplasmic Reticulum-associated Degradation in Saccharomyces cerevisiae

“…Explosive progress in glycobiology during the past decade has unveiled most, if not all, of the biosynthetic pathways for N-glycans. However, the mechanisms by which N-glycans are catabolized in cells are relatively unknown (77). This is especially the case for the metabolism of fOSs.…”

Dual Functions for Cytosolic α-Mannosidase (Man2C1)

“…Eluted compounds were detected by fluorescence at ex ϭ 310 nm and em ϭ 380 nm. ␣-Mannosidase digestion of PA-labeled free oligosaccharides was carried out as described previously (23), and the ␣-mannosidase-sensitive peaks in the Hex [5][6][7][8][9] HexNAc fractions (12) were then measured. For quantification, the PA-Glc 6 in the PA-glucose oligomer (TaKaRa Bio Inc.; 2 pmol/l) was used as a reference.…”

The cytoplasmic peptide:N-glycanase (NGLY1) — Structure, expression and cellular functions

“…While the biosynthetic pathway for N -glycosylation has been well clarified in mammals and yeast, many issues remain to be clarified in terms of their catabolism, even in this “post-genome” era. It is well known that the degradation of N -glycoproteins occurs predominantly in lysosomes (Winchester, 2005; Suzuki, 2009), whereas the occurrence of a “non-lysosomal” degradation pathway has also been revealed during the past decade (Suzuki, 2007; Suzuki and Harada, 2014; Harada et al, 2015a). …”