This process is key to a number of cellular functions such as signal recognition and cell adhesion. Glycoprotein function, stability, and metabolism in particular are dependent upon correct sialylation.
What is Sialic Acid?
Sialic acid is a general term for N or O substituted derivatives of neuraminic acid (a 9-carbon backbone monosaccharide) which are widely expressed terminal carbohydrates on cell surface glycoproteins and glycolipids of eukaryotic cells.
N-glycolylneuraminic and N-acetylneuraminic acid
There are two common mammalian sialic acids: N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) which are synthesized by 4 consecutive reactions from UDP-N-acetylglucosamine.
The bi-functional enzyme UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (UDP-GlcNAc 2-epimerase) performs the first two key reactions of sialic acid biosynthesis.
Due to the abundant presence on the surface of eukaryotic cells, sialic acids play key roles in several pathophysiological processes including; metastasis, tumor progression, inflammation and viral infection.
Staining using fluorescein-labelled Sambucus nigra (SNA) is impacted in CMAS and SLC35A1 knockout cell lines. Cells were washed with PBS, fixed with 4% paraformaldehyde and stained with fluorescein-labelled SNA lectin (Vector Labs). HAP1 wild-type cells were compared to cells bearing a frameshift mutation in CMAS or SLC35A1
Examples of popular knockout cell lines for Sialylation