Reactome | O-linked glycosylation of mucins

O-linked glycosylation of mucins

Stable Identifier

R-HSA-913709

DOI

10.3180/REACT_115606.1

Type

Pathway

Species

Homo sapiens

ReviewStatus

5/5

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Mucins are a family of high molecular weight, heavily glycosylated proteins (glycoconjugates) produced by epithelial tissues in most metazoa. Mucins' key characteristic is their ability to form gels; therefore they are a key component in most gel-like secretions, serving functions from lubrication to cell signalling to forming chemical barriers. To date, there are approximately 20 genes that express mucins. Mature mucins are composed of two distinct regions:
(1) The amino- and carboxy-terminal regions are very lightly glycosylated, but rich in cysteines. The cysteine residues participate in establishing disulfide linkages within and among mucin monomers.
(2) A large central region rich in serine, threonine and proline residues called the variable number of tandem repeat (VNTR) region which can become heavily O-glycosylated with hundreds of O-GalNAc glycans.
N-acetyl-galactosamine (GalNAc) is the first glycan to be attached, forming the simplest mucin O-glycan. After this, several different pathways are possible generating "core" structures. Four core structures are commonly formed, several others are possible but infrequent. O-linked glycans are often capped by the addition of a sialic acid residue, terminating the addition of any more O-glycans (Brockhausen et al, 2009; Tarp and Clausen, 2008).

Literature References

PubMed ID	Title	Journal	Year
17988798	Mucin-type O-glycosylation and its potential use in drug and vaccine development Tarp, MA, Clausen, H	Biochim Biophys Acta	2008
	O-GalNAc Glycans Brockhausen, I, Schachter, H, Stanley, P, Stanley, P, Varki, A, Cummings, RD, Esko, JD, Freeze, HH, Bertozzi, CR, Hart, GW, Etzler, ME		2009