Salivary mucin MG1 is comprised almost entirely of different glycosylated forms of the MUC5B gene product

Thornton, David J.; Khan, Nagma; Mehrotra, Ravi; Howard, Marj; Veerman, E.C.I.; Packer, Nicolle H.; Sheehan, John K.

doi:10.1093/glycob/9.3.293

Cited by 144 publications

(128 citation statements)

References 26 publications

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“…Multiangle light scattering coupled to size exclusion chromatography (SEC/MALS) measurements to determine the macromolecular integrity of purified salivary MUC5B indicated that after 60 minutes of elastase exposure, at least 80% to 90% of the mucins maintained a molecular weight of approximately 38 MDa (Figure 3B), i.e., that typical of purified MUC5B (23,24). A typical dRI trace (solid lines) and the molecular mass distribution (dotted lines) in the void (V o ) volume region are shown in Figure 3B.…”

Section: Figurementioning

confidence: 99%

Cystic fibrosis airway secretions exhibit mucin hyperconcentration and increased osmotic pressure

Henderson¹,

Ehré²,

Button³

et al. 2014

J. Clin. Invest.

292

278

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The pathogenesis of mucoinfective lung disease in cystic fibrosis (CF) patients likely involves poor mucus clearance. A recent model of mucus clearance predicts that mucus flow depends on the relative mucin concentration of the mucus layer compared with that of the periciliary layer; however, mucin concentrations have been difficult to measure in CF secretions. Here, we have shown that the concentration of mucin in CF sputum is low when measured by immunologically based techniques, and mass spectrometric analyses of CF mucins revealed mucin cleavage at antibody recognition sites. Using physical size exclusion chromatography/differential refractometry (SEC/dRI) techniques, we determined that mucin concentrations in CF secretions were higher than those in normal secretions. Measurements of partial osmotic pressures revealed that the partial osmotic pressure of CF sputum and the retained mucus in excised CF lungs were substantially greater than the partial osmotic pressure of normal secretions. Our data reveal that mucin concentration cannot be accurately measured immunologically in proteolytically active CF secretions; mucins are hyperconcentrated in CF secretions; and CF secretion osmotic pressures predict mucus layer-dependent osmotic compression of the periciliary liquid layer in CF lungs. Consequently, mucin hypersecretion likely produces mucus stasis, which contributes to key infectious and inflammatory components of CF lung disease.

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Section: Figurementioning

confidence: 99%

Cystic fibrosis airway secretions exhibit mucin hyperconcentration and increased osmotic pressure

Henderson¹,

Ehré²,

Button³

et al. 2014

J. Clin. Invest.

292

278

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“…These different mucin glycoforms are secreted in the oral cavity by physically separated salivary glands. [29][30][31][32] The production and presence of these various glycoforms of the mucins could well play a role in the adhesion of the various oral bacteria that also show a preferred localization at the various sites in the oral cavity (see below).…”

Section: Mucinsmentioning

confidence: 99%

Mucin-bacterial interactions in the human oral cavity and digestive tract

et al. 2010

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“…Effects on purified mucins (3,(33)(34)(35) have shown the characteristics of electrostatic interactions involving carbohydrate structures such as sialic acids (3,33,35) and have not been specific for calcium (3,31). The standard methods developed for mucin purification (5,37,38) have routinely used 6 M GdmCl as a denaturing solvent to ensure the removal of associated proteins. Present results show that such treatment destroys the calcium effects in MUC5B preparations, but as the oligosaccharides remain intact this rules out their participation in the calcium-dependent effects on saliva.…”

Section: Table III Peptides Identified By Esi-ms-ms Analysismentioning

confidence: 99%

Calcium-dependent Protein Interactions in MUC5B Provide Reversible Cross-links in Salivary Mucus

Raynal

Hardingham

Sheehan³

et al. 2003

Journal of Biological Chemistry

134

114

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The macromolecular organization within saliva was investigated by tracer diffusion measurements of fluorescent polystyrene microspheres by fluorescence recovery after photobleaching using a confocal microscope (confocal-FRAP). There was a concentrationdependent reduction in microsphere diffusion; this was much greater in the presence of calcium (10 mM) and was reduced by the addition of EGTA (10 mM). These effects on tracer diffusion showed that native saliva contained a macromolecular organization that was sensitive to free calcium concentrations. This was supported by a major increase in the weight average molecular weight of the high molecular weight mucin fraction in saliva (10 -62 ؋ 10 6 ) and an increase in intrinsic viscosity of saliva (733 to 1203 ml/g) both caused by calcium. Analysis of the change in tracer diffusion in saliva showed a 20-fold increase in the apparent pore size (from 130 nm in 10 mM CaCl 2 to 2600 nm in 10 mM EGTA at physiological concentration). The effect was specific for calcium and was unaffected by up to 2 M NaCl. The calcium binding activity was contained in a high buoyant density fraction of saliva excluded from Sepharose CL-2B. Calcium binding to this fraction gave an approximate K d of 7 ؋ 10 ؊6 M, and the binding was irreversibly destroyed by treatment with 6 M guanidinium chloride and by mild reduction, suggesting it to be to a protein site. This fraction of saliva was shown to contain MUC5B as the single major protein species by positive ion electrospray ionization-tandem mass spectrometry analysis. The results suggested that oligomeric MUC5B in saliva is assembled into much larger linear or branched assemblies through calcium-mediated protein cross-links.Mucus forms a viscoelastic gel that coats the epithelial surfaces in humans and other vertebrates. The properties of the gel have been interpreted as being predominantly due to entanglement of the long, high molecular weight oligomeric mucins (1, 2). Mucus has also been described as a network weakly cross-linked by non-covalent bonds (3, 4) and suggested mechanisms of interaction have included interchain hydrophobic interactions (5) and carbohydrate-carbohydrate interactions between the mucins (6 -9). Mucus rheology is affected by many factors, including hydration (2), pH (10), and ion content (11-13). Thus the supramolecular organization of the mucus layer is complex, and the molecular basis of this organization remains poorly defined.A layer of mucus coats the surfaces of the gastrointestinal, reproductive, and respiratory tracts as well as the eyes and oral cavity (14). This layer is the bodies' first line of defense against chemical, physical, and biological insult and a change in this barrier will compromise health. For example, in the airways overproduction of mucus with aberrant rheological properties is a feature of asthma, cystic fibrosis, and chronic obstructive pulmonary disease. In these situations the change in the physical properties of the barrier leads to a breakdown in mucus clearance from the airways with...

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Salivary mucin MG1 is comprised almost entirely of different glycosylated forms of the MUC5B gene product

Cited by 144 publications

References 26 publications

Cystic fibrosis airway secretions exhibit mucin hyperconcentration and increased osmotic pressure

Cystic fibrosis airway secretions exhibit mucin hyperconcentration and increased osmotic pressure

Mucin-bacterial interactions in the human oral cavity and digestive tract

Calcium-dependent Protein Interactions in MUC5B Provide Reversible Cross-links in Salivary Mucus

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