Structure, biosynthesis, and function of salivary mucins

Abstract

The glandular secretions of the oral cavity lining the underlying buccal mucosa are highly specialized fluids which provide lubrication, prevent mechanical damage, protect efficiently against viral and bacterial infections, and promote the clearance of external pollutants. This mucus blanket contains large glycoproteins termed mucins which contribute greatly to the viscoelastic nature of saliva and affect its complex physiological activity. The protein core of mucins consists of repetitive sequences, rich in O-glycosylated serine and threonine, and containing many helix-breaking proline residues. These features account for the extended, somewhat rigid structure of the molecule, a high hydrodynamic volume, its high buoyant density, and high viscosity. The oligosaccharide moiety of salivary mucins accounts for up to 85% of their weight. The oligosaccharide side chains exhibit an astonishing structural diversity. The isolation, composition, structure, molecular characteristics, and functional relevance of salivary mucins and their constituents is discussed in relation to recent advancements in biochemistry and molecular biology.

Native and/or asialo‐Tamm‐Horsfall glycoproteins Sd(a+) are important receptors for Triticum vulgaris (wheat germ) agglutinin and for three toxic lectins (abrin‐a, ricin and mistletoe toxic lectin‐I)

“…During the past two decades, this analytical system has been successfully used as a valuable tool to characterize the saccharide-binding affinity of lectins [13,[18][19][20][21][22][23][24][25][26], as such studies can provide insight into the specificities and size parameters of the lectin-glycan interactions. From the results of the QPA (Table 1 and Fig.…”

Characterization of the carrier state in porcine reproductive and respiratory syndrome virus infection

“…We speculate that recovery of virus was enhanced by the presence of mucin in the sample, known to be highly protective of viruses (Schoenbaum et al, 1990;Wu et al, 1994), and the fact that oropharyngeal scrapings samples were minimally processed prior to being assayed for virus. On the other hand, recovery and/or detection of virus in tonsil tissue samples may be inhibited by the greater dilution of the sample, more extensive sample processing, and the presence of non-specific anti-viral compounds.…”

“…The epithelium lining the surface of the tonsil and lumen of the crypts provides a strong physical barrier against the entry of pathogens (Belz and Heath 1996). Mucin, a glycoprotein present in mucus sections, lines the gastrointestinal tract and upper respiratory tract, including the oral cavity and tonsils, and provides innate immunity by preventing the adherence of bacteria to epithelial cells (Wu 1994). Complement, activated through either the classical or the alternative pathway, is probably present within the porcine tonsil (Laufer 2000;Zwimer 1989).…”

Biochemical analysis of a bladder-cancer-associated mucin: structural features and epitope characterization

“…As neuraminidase treatment suggests that the three mAbs react with sialylated epitopes, they were tested on BSM, OSM, PSM A + and PSM A − purified mucins expressing sialyl-Tn and some other sialylated oligosaccharides [35]. mAb B72.3 to sialyl-Tn was positive on the four mucins whereas the M series mAbs were negative (results not shown).…”