Human mucin glycoproteins: varied structures predict diverse properties and specific functions.

It has been clear for some time now that mucin glycoproteins have extensive, highly glycosylated tandem repeat domains. What is becoming increasingly apparent, however, is the diversity of unique sequences present on different mucins. Variations in mucin-unique sequences clearly result in major differences in physical and biological properties. MUC1-unique sequences are needed for membrane binding, while MUC2-unique sequences apparently mediate polymerization. As the sequences of other mucins are determined, undoubtedly additional structures will be determined that confer specific properties and functions upon this interesting class of glycoconjugates.