The group of secreted mucins has eight members: five genes encode the gelforming
mucins (MUC2, MUC5AC, MUC5B, MUC6 and MUC19) and three genes
encode the soluble mucins (MUC7, MUC8 and MUC9). Gel-forming mucins share
structural and evolutionary features with von Willibrand Factor. Soluble mucins differ
from gel-forming mucins in that the former all do not have the von Willibrand Factor
specific domains while mucin specific tandem repeat-containing domain is a common
feature of all secreted mucins. Genes encoding the soluble mucins are located at
different chromosomes, whereas all gel-forming mucin genes except MUC19 are
clustered on chromosome locus 11p15.5 and the MUC19 gene is located on
chromosome 12. Structural aspects and functions of the secreted mucins are discussed.
Keywords: Secreted mucins, classification, MUC2, MUC5AC, MUC5B, MUC6,
MUC19, MUC7, MUC8, MUC9, chromosomal localization.
