mucin-2; MUC-2; intestinal mucin-2 (MUC2, SMUC)

Function: - coats epithelia of the intestines, airways, & other mucus membrane-containing organs - thought to provide a protective, lubricating barrier against particles & infectious agents at mucosal surfaces - major constituent of both the inner & outer mucus layers of the colon & may play a role in excluding bacteria from the inner mucus layer - may undergo proteolytic cleavage in the outer mucus layer of the colon, contributing to the expanded volume & loose nature of this layer which allows for bacterial colonization in contrast to the inner mucus layer which is dense & devoid of bacteria - at low pH of 6 & under, undergoes autocatalytic cleavage in vitro in the N-terminal region of the fourth VWD domain; it is likely that this also occurs in vivo & is triggered by the low pH of the late secretory pathway - dimerizes in the endoplasmic reticulum via its C-terminal region & polymerizes via its N-terminal region by disulfide-linked trimerization - interacts with FCGBP Structure: - homotrimer; disulfide-linked - O-glycosylated - contains 1 CTCK (C-terminal cystine knot-like) domain - contains 1 TIL (trypsin inhibitory-like) domain - contains 2 VWFC domains - contains 4 VWFD domains Compartment: - secreted - in the intestine, secreted into the inner & outer mucus layers (putative) Expression: - colon, small intestine, colonic tumors, bronchus, cervix & gall bladder Polymorphism: - the number of repeats is highly polymorphic & varies among different alleles

General

mucin phosphoprotein secreted protein

Properties

SIZE: entity length = 5179 aa MW = 540 kD COMPARTMENT: extracellular compartment MOTIF: signal sequence {1-20} MOTIF: Ser phosphorylation site {S16} Ser phosphorylation site {S21} Thr phosphorylation site {T25} VWFD domain {36-240} MOTIF: cysteine residue {C59} MODIFICATION: cysteine residue {C67} cysteine residue {C67} MODIFICATION: cysteine residue {C59} N-glycosylation site {N163} TIL {295-351} VWFD domain {390-604} MOTIF: N-glycosylation site {N423} N-glycosylation site {N670} N-glycosylation site {N770} VWFD domain {859-1065} MOTIF: N-glycosylation site {N894} N-glycosylation site {N1139} N-glycosylation site {N1154} N-glycosylation site {N1215} N-glycosylation site {N1230} N-glycosylation site {N1246} consensus repeat {1401-1747} (21) N-glycosylation site {N1787} N-glycosylation site {N1820} N-glycosylation site {N4339} N-glycosylation site {N4351} N-glycosylation site {N4362} N-glycosylation site {N4373} N-glycosylation site {N4422} N-glycosylation site {N4438} VWFD domain {4480-4690} MOTIF: peptide motif {4486-4487} N-glycosylation site {N4502} N-glycosylation site {N4616} N-glycosylation site {N4627} N-glycosylation site {N4752} N-glycosylation site {N4787} VWFC domain {4815-4886} MOTIF: N-glycosylation site {N4881} N-glycosylation site {N4888} VWFC domain {4924-4991} MOTIF: N-glycosylation site {N4955} N-glycosylation site {N4970} N-glycosylation site {N5019} N-glycosylation site {N5038} N-glycosylation site {N5069} C-terminal cystine knot {5075-5160} MOTIF: cysteine residue {C5075} MODIFICATION: cysteine residue {C5122} cysteine residue {C5089} MODIFICATION: cysteine residue {C5136} cysteine residue {C5098} MODIFICATION: cysteine residue {C5152} cysteine residue {C5102} MODIFICATION: cysteine residue {C5154} cysteine residue {C5122} MODIFICATION: cysteine residue {C5075} cysteine residue {C5136} MODIFICATION: cysteine residue {C5089} cysteine residue {C5152} MODIFICATION: cysteine residue {C5098} cysteine residue {C5154} MODIFICATION: cysteine residue {C5102}

Database Correlations

OMIM 158370 UniProt Q02817 PFAM correlations Entrez Gene 4583 Kegg hsa:4583