Mucin 13, Cell Surface Associated (MUC13)

The rodent and human MUC13 cDNAs contain a series of CA dinucleotide repeats and an alternative polyadenylation signal. The deduced 512-amino acid human protein has a calculated molecular mass of 54.7 kD. Both human and rodent MUC13 have an N-terminal signal peptide, followed by a serine/threonine-rich mucin repeat domain, a cysteine-rich EGF-like domain, a SEA module, 2 more cysteine-rich EGF-like domains, a transmembrane region, and a cytoplasmic tail. The mucin repeat domain is predicted to be heavily O-glycosylated, and MUC13 also has sites for N-glycosylation and phosphorylation. Northern blot analysis detected highest expression of a 3.2-kb transcript in colon and trachea, with moderate levels in kidney, small intestine, appendix, and stomach, and low levels in several other tissues.