Mucins are a family of high
molecular weight, heavily
glycosylated proteins (
glycoconjugates) produced by
epithelial tissues in most organisms of
Kingdom Animalia. Mucins' key characteristic is their ability to form
gels; therefore they are a key component in most gel-like secretions, serving functions from lubrication to cell signalling to forming chemical barriers. They often take an inhibitory role. Some mucins are associated with controlling
mineralization, including
nacre formation in
mollusks,
calcification in
echinoderms and bone formation in vertebrates. They bind to pathogens as part of the immune system. Overexpression of the mucin proteins, especially
MUC1, is associated with many types of cancer.
