| Modification Notes |
ST8Sia III (ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 3), also known as SIAT8C, is a 380 amino acid single-pass type II membrane protein that localizes to the membrane of the Golgi apparatus. Expressed in fetal liver and fetal and adult brain, the expression of ST8Sia III is tissue-specific and developmentally regulated. ST8Sia III plays an important role in protein modification and glycosylation, and functions to catalyze the transfer of sialic acid through alpha-2,8-linkage to intact fetuin glycoprotein. ST8Sia III can form polysialic acid (PSA) in vitro directly on alpha-2,3-, alpha-2,6- or alpha-2,8-linked sialic acid. PSA is an important regulator of neuronal plasticity and is present in embryonic brain tissue, where it interacts with NCAM (neural cell adhesion molecule) and plays a crucial role in fetal brain development. The gene encoding ST8Sia III maps to human chromosome 18q21.31. |