MUC1-C (D5K9I) XP^® Rabbit mAb #16564

Mucins represent a family of glycoproteins characterized by repeat domains and dense O-glycosylation (1). MUC1 (or mucin 1) is aberrantly overexpressed in most human carcinomas. Increased expression of MUC1 in carcinomas reduces cell-cell and cell-ECM interactions. MUC1 is cleaved proteolytically, and the large ectodomain can remain associated with the small 25 kDa carboxy-terminal domain that contains a transmembrane segment and a 72-residue cytoplasmic tail (1). MUC1 interacts with ErbB family receptors and potentiates ERK1/2 activation (2). MUC1 also interacts with β-catenin, which is regulated by GSK-3β, PKCγ, and Src through phosphorylation at Ser44, Thr41, and Tyr46 of the MUC1 cytoplasmic tail (3-5). Overexpression of MUC1 potentiates transformation (6) and attenuates stress-induced apoptosis through the Akt or p53 pathways (7,8).
MUC1-C is the carboxy-terminal transmembrane subunit of MUC1 resulting from proteolytic cleavage of the full length protein. MUC1-N is the amino-terminal subunit, which can be tethered to MUC1-C, or released from the plasma membrane. MUC1-C interacts with receptor tyrosine kinases, β-catenin and other signaling proteins, and is thought to induce activation of MAPK, Akt and Wnt pathways. Due to its signaling functions and expression in human cancer, MUC1-C is a potential therapeutic target (reviewed in 9).