Tandem-repeating region of mucin, epiglycanin-like
The unusual mucin, epiglycanin, is membrane-bound at the C-terminus but has a long region of this tandem-repeat at the N-terminus. It was the first mucin identified to be associated with the malignant behaviour of carcinoma cells. Mouse Muc21/epiglycanin is thought to be a highly glycosylated molecule, which makes it likely that its function is dependent on its glycoforms. Cells expressing Muc21 are significantly less adherent to each other and to extracellular matrix components than control cells, and this loss of adhesion is mediated by the TR portion of Muc21. This family also now contains the repeat that was the C. elegans protein of unknown function (DUF801).