Table 1.
STs and sialidases - functions, targets, and locations (Harduin-Lepers, 2010; Audry et al., 2011; Miyagi and Yamaguchi, 2012; Glanz et al., 2019).
| Sialyltransferases | Functions | Targets/Substrates | Locations |
|---|---|---|---|
| Sialidases | |||
| ST6GalNAc-I to VI | Transfers Sia to the hydroxyl group in C6 of the GalNac in O-linked glycoproteins (ST6GalNAc-I, II, IV) or glycolipids (ST6GalNAc-III, V, VI) |
O-glycoproteins (ST6GalNac-I, II) O-glycoproteins/glycolipids (ST6GalNac-III, IV) Glycoproteins/glycolipids (ST6GalNac-V) Glycolipids (ST6GalNac-VI) |
Golgi apparatus |
| ST6Gal-I and II | Transfers Sia to the hydroxyl group in C6 of a terminal galactose residue | N-glycoproteins (ST6Gal-I, II) | Golgi apparatus |
| ST3Gal-I to VI | Catalyzes the α2,3-linkage between Neu5Ac and C3 of terminal galactose residues found on glycoproteins and glycolipids |
O-glycoproteins/glycolipids (ST3Gal-I and II) Glycoproteins (ST3Gal-III) Glycoproteins/glycolipids (ST3Gal-IV and VI) Glycolipids (ST3Gal-V) |
Golgi apparatus |
| ST8Sia-I to VI | Transfers Neu5Ac to the hydroxyl group in C8 of another terminal Neu5Ac residue | Glycolipids (ST8Sia-I, V) Glycoproteins (ST8Sia-II, IV) Glycolipids/glycoproteins (ST8Sia-III) O-glycoproteins (ST8Sia-VI) |
Golgi apparatus |
| NEU 1 | Phagocytosis Elastic fiber assembly Exocytosis Immune responses Lysosome catabolism |
Oligosaccharides Glycopeptides |
Lysosomes |
| NEU 2 | Neural cells and myoblast differentiation | Oligosaccharides Glycoproteins Gangliosides |
Cytosol and plasma membrane |
| NEU 3 | Adhesion Neural cells differentiation Apoptosis |
Gangliosides | Plasma membrane |
| NEU 4 | Adhesion Neural cells differentiation Apoptosis |
Oligosaccharides Glycoproteins Gangliosides |
Lysosomes, mitochondria and endoplasmic reticulum |