MUC1 TR

This 20-amino-acid tandem repeat (TR) sequence belongs to the extracellular domain of mucin. It contains five possible O-glycan attachment sites and this sequence is repeated 20-120 times. The action of several GalNTs are needed to glycosylate all five acceptor sites. MUC1 is a transmembrane mucin expressed on the apical surface of most epithelial cells, including the mammary glands, and also on hematopoietic cells and in bone marrow. MUC1 is highly overexpressed in many forms of cancer, in particular breast carcinomas.