Thought to provide a protective, lubricating barrier against particles and infectious agents at mucosal surfaces.

Expressed in corneal and conjunctival epithelia (at protein level). Overexpressed in ovarian carcinomas and ovarian low malignant potential (LMP) tumors as compared to the expression in normal ovarian tissue and ovarian adenomas.

Contains 2 ANK repeats.
Contains 56 SEA domains.

Composed of three domains, a Ser-, Thr-rich N-terminal domain, a repeated domain containing more than 60 partially conserved tandem repeats of 156 amino acids each (AAs 12061-21862) and a C-terminal transmembrane contain domain with a short cytoplasmic tail.

Heavily O-glycosylated; expresses both type 1 and type 2 core glycans.
Heavily N-glycosylated; expresses primarily high mannose and complex bisecting type N-linked glycans.
May be phosphorylated. Phosphorylation of the intracellular C-terminal domain may induce proteolytic cleavage and the liberation of the extracellular domain into the extracellular space.
May contain numerous disulfide bridges. Association of several molecules of the secreted form may occur through interchain disulfide bridges providing an extraordinarily large gel-like matrix in the extracellular space or in the lumen of secretory ducts.

Cell membrane. Secreted > extracellular space. May be liberated into the extracellular space following the phosphorylation of the intracellular C-terminus which induces the proteolytic cleavage and liberation of the extracellular domain.