Mucin 3A (MUC3A) (MUC3A)

Mucin 3A (MUC3A) is a large, highly glycosylated transmembrane protein primarily expressed on the apical surface of intestinal and respiratory epithelial cells. As a member of the mucin family, it is characterized by a central domain of tandem repeats rich in serine and threonine residues that undergo extensive O-glycosylation to form a protective and lubricating mucus barrier. Beyond its structural role, MUC3A functions as a signaling molecule through its extracellular epidermal growth factor (EGF)-like domains and its cytoplasmic tail, which interact with intracellular pathways such as PI3K/Akt/mTOR and stabilize the epidermal growth factor receptor (EGFR). In various malignancies, including gastric, lung, and colorectal cancers, MUC3A is frequently overexpressed and acts as an oncogene that promotes tumor progression, metastasis, and chemoresistance. While no drugs currently target MUC3A in clinical practice, it is a significant focus of research for the development of monoclonal antibodies, CAR T-cell therapies, and small-molecule inhibitors of mucin synthesis like Talniflumate.

Other names

MUC3Mucin-3Mucin 3BMUC3BMUC-3Intestinal mucin-3Mucin 3A cell surface associated

MUC3A acts as a physical and biochemical barrier and a signaling scaffold; drugs such as Talniflumate indirectly target it by inhibiting GCNT3 to disrupt mucin glycan synthesis, while experimental agents aim to block its extracellular EGF-like domains to inhibit oncogenic signaling through the PI3K/Akt/mTOR and EGFR pathways.