The existence of high-molecular-weight glycoproteins in saliva and salivary secretions has been recognized for nearly 30 years. These proteins, called mucins, are essential for oral health and perform many diverse functions in the oral cavity. Mucins have been intensively studied, and much has been learned about their biochemical properties and their interactions with oral micro-organisms and other salivary proteins. In the past several years, the major high-molecular-weight @entity3558 in salivary secretions has been identified as @entity5090 , one of a family of 11 @entity1 @entity3558 gene products expressed in tissue-specific patterns in the gastrointestinal, respiratory, and reproductive tracts. @entity5090 is one of four gel-forming mucins which exist as multimeric proteins with molecular weights greater than 20-40 million daltons. The heavily glycosylated @entity3558 multimers form viscous layers which protect underlying epithelial surfaces from microbial, mechanical, and chemical assault. Another class of @entity3558 molecules, the membrane-bound mucins, is structurally and functionally distinct from the gel-forming mucins. These proteins do not form multimers and can exist as both secreted and membrane-bound forms, with the latter anchored to epithelial cell membranes through a short membrane-spanning domain. In the present work, we show that two of the membrane-bound mucins, @entity2355 and @entity5088 , are expressed in all major @entity1 salivary glands as well as in buccal epithelial cells. While the functions of these mucins in the oral environment are not understood, it is possible that they form a structural framework on the cell surface which not only is cytoprotective, but also may serve as a scaffold upon which @entity5090 , and possibly other salivary proteins, assemble.

Heterogeneity of high-molecular-weight XXXX salivary mucins.

@entity1 :: ('9606', 'Species') :: ['human'] @entity5090 :: ('727897', 'Gene') :: ['MUC5B'] @entity3558 :: ('100508689', 'Gene') :: ['mucin'] @entity2355 :: ('4582', 'Gene') :: ['MUC1'] @entity5088 :: ('4585', 'Gene') :: ['MUC4']
@entity1 :: (9606,Species) :: ['human']
