Mucins are major glycoprotein components of the mucous that coats the surfaces of cells
lining the respiratory, digestive, and urogenital tracts, and in some amphibia, the skin. They
function to protect epithelial cells from infection, dehydration, and physical or chemical
injury, as well as to aid the passage of materials through a tract. Individual organisms make
several structurally different mucins, and a given mucin may be found in more than one
organ (see Supplemental Material). Members of the mucin family can differ considerably in …