Reactome | ST6GAL1 transfers Neu5Ac to terminal Gal of N-glycans

ST6GAL1 transfers Neu5Ac to terminal Gal of N-glycans

Stable Identifier

R-HSA-975902

Type

Reaction [transition]

Species

Homo sapiens

Compartment

Golgi membrane, Golgi lumen

Synonyms

Addition of alpha-2,6-sialic acid to terminal galactose of N-glycans by ST6GAL1

ReviewStatus

5/5

Locations in the PathwayBrowser

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Metabolism of proteins (Homo sapiens)

- Post-translational protein modification (Homo sapiens)
  - Asparagine N-linked glycosylation (Homo sapiens)
    - Transport to the Golgi and subsequent modification (Homo sapiens)
      - N-glycan antennae elongation in the medial/trans-Golgi (Homo sapiens)
        
        N-Glycan antennae elongation (Homo sapiens)
        
        ST6GAL1 transfers Neu5Ac to terminal Gal of N-glycans (Homo sapiens)

General

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ST6GAL1 transfers Neu5Ac to terminal Gal of N-glycans

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Addition of sialic acid to galactose-containing N-glycan. Sialic acid is usually found at terminal positions of the N-glycan. This imparts a negative charge at neutral pH which affects the chemico-physical and biological properties of the N-glycans (for review, see Schauer 2000); moreover, this modification can lead to the addition of extraordinarily long antennae such as polysialic acid (hundreds of sials) or polylactosamine repeats (dozens of disaccharide repeats) (Harduin-Lepers 2001), while the number of modifications on the antennae of N-glycans is usually lower.
There are over 20 sialyltransferases known in humans, 5 of which are known to act on N-glycans. Beta-galactoside alpha-2,6-sialyltransferase 1 (ST6GAL1) is the only sialyltransferase known to transfer sialic acid to galactose on N-Glycans (Dall'Olio 2000). A second beta-galactoside alpha-2,6-sialyltransferase has been characterized, but this enzyme acts mainly on oligosaccharides (Krzewinski-Recchi et al. 2003). Neu5Ac can also be added via an alpha-2,3-linkage to galactose on N-glycans by CMP-N-acetylneuraminate-beta-galactosamide-alpha-2,3-sialyltransferase 4 (ST3GAL4) (Ellies et al. 2002). ST8Sia II (ST8SIA2), ST8Sia III (ST8SIA3), and ST8Sia IV (ST8SIA6) have alpha-2,8-activity (Angata et al. 1997, Angata et al. 2000, Angata & Fuduka 2003).

Literature References

PubMed ID	Title	Journal	Year
11425186	The sialyl-alpha2,6-lactosaminyl-structure: biosynthesis and functional role Dall'Olio, F	Glycoconj J	2000
11530204	The human sialyltransferase family Harduin-Lepers, A, Vallejo-Ruiz, V, Krzewinski-Recchi, MA, Samyn-Petit, B, Julien, S, Delannoy, P	Biochimie	2001
10766765	Differential biosynthesis of polysialic acid on neural cell adhesion molecule (NCAM) and oligosaccharide acceptors by three distinct alpha 2,8-sialyltransferases, ST8Sia IV (PST), ST8Sia II (STX), and ST8Sia III Angata, K, Suzuki, M, McAuliffe, J, Ding, Y, Hindsgaul, O, Fukuda, M	J Biol Chem	2000
11421344	Achievements and challenges of sialic acid research Schauer, R	Glycoconj J	2000
12603328	Identification and functional expression of a second human beta-galactoside alpha2,6-sialyltransferase, ST6Gal II Krzewinski-Recchi, MA, Julien, S, Juliant, S, Teintenier-Lelièvre, M, Samyn-Petit, B, Montiel, MD, Mir, AM, Cerutti, M, Harduin-Lepers, A, Delannoy, P	Eur J Biochem	2003
12097641	Sialyltransferase ST3Gal-IV operates as a dominant modifier of hemostasis by concealing asialoglycoprotein receptor ligands Ellies, LG, Ditto, D, Levy, GG, Wahrenbrock, M, Ginsburg, D, Varki, A, Le, DT, Marth, JD	Proc Natl Acad Sci U S A	2002
12765789	Polysialyltransferases: major players in polysialic acid synthesis on the neural cell adhesion molecule Angata, K, Fukuda, M	Biochimie	2003
9054414	Human STX polysialyltransferase forms the embryonic form of the neural cell adhesion molecule. Tissue-specific expression, neurite outgrowth, and chromosomal localization in comparison with another polysialyltransferase, PST Angata, K, Nakayama, J, Fredette, B, Chong, K, Ranscht, B, Fukuda, M	J Biol Chem	1997