Isolation of Human Salivary Mucin MG2 by a Novel Method and Characterization of Its Interactions with Oral Bacteria

Liu, Bing; Rayment, Sean A.; Oppenheim, Frank G.; Troxler, Robert F.

doi:10.1006/abbi.1999.1141

Cited by 54 publications

(55 citation statements)

References 27 publications

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“…Mucin MG2 protects lactoferrin from proteolytic attack, and the interaction of mucin MG2 with oral bacteria exhibits bactericidal activity (29). Mucin MG2 was observed to bind to some unknown surface components of S. mutans (18). Our results indicate that surface enolase is one ligand responsible for the binding of salivary mucin MG2 to S. mutans.…”

Section: Fig 4 Ability Of S Mutansmentioning

confidence: 69%

“…Salivary mucin MG2 is a 180-kDa glycoprotein (22). Mucin MG2 binds to several oral microbes, including S. mutans, Actinobacillus actinomycetemcomitans, and Candida albicans, and forms heterotypic complexes with salivary proteins, including secretory immunoglobulin A (SIgA) and lactoferrin (4,15,18,19,29).Enolase is a 47-kDa cytoplasmic enzyme in the glycolytic pathway (21). There are three distinct isoforms (␣, ␤, and ␥) of enolase, each with the same molecular mass.…”

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confidence: 99%

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Streptococcus mutans Surface α-Enolase Binds Salivary Mucin MG2 and Human Plasminogen

Ge¹,

Catt

Gregory

2004

Infect Immun

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Matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis identified enolase as a cell surface component of Streptococcus mutans, which was confirmed by enzyme-linked immunosorbent assay, Western blotting, and transmission electron microscopy. Surface enolase was demonstrated to bind to human plasminogen and salivary mucin MG2. The results suggested a role for enolase in S. mutans attachment, clearance, or breach of the bloodstream barrier.Streptococcus mutans is an alpha-hemolytic and nongroupable streptococcus, which causes dental caries and occasionally bacterial endocarditis (BE) (20). Some surface proteins of S. mutans are virulence factors with functions critical to viability, such as adhesion (2). Adhesion is one of the most important steps in the pathogenicity of microorganisms, and bacterial cell surface-mediated interactions with salivary proteins may be the first step in S. mutans attachment to a tooth surface coated with salivary pellicle or saliva-coated plaque (11). Liu et al. reported that S. mutans binds to salivary mucins, but the specific molecule responsible for this binding was unknown (18). Salivary mucin MG2 is a 180-kDa glycoprotein (22). Mucin MG2 binds to several oral microbes, including S. mutans, Actinobacillus actinomycetemcomitans, and Candida albicans, and forms heterotypic complexes with salivary proteins, including secretory immunoglobulin A (SIgA) and lactoferrin (4,15,18,19,29).Enolase is a 47-kDa cytoplasmic enzyme in the glycolytic pathway (21). There are three distinct isoforms (␣, ␤, and ␥) of enolase, each with the same molecular mass. ␣-Enolase is the isoform typically found in bacteria. Surface ␣-enolase has been recently identified on Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus pneumonia, Streptococcus oralis, and A. actinomycetemcomitans (3,13,16,25,32). Surface enolase of S. pyogenes binds and activates human plasminogen, a molecule which plays a crucial role in fibrinolysis, homeostasis, and the degradation of extracellular matrix (8). Proteins, such as enolase, with exposed carboxyl-terminal lysines on the cell surface can bind and promote plasminogen activation (33).In the present study, we identified ␣-enolase from a cell surface protein preparation of S. mutans A32-2 by two-dimensional polyacrylamide gel electrophoresis (PAGE) and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. The results of enzyme-linked immunosorbent assay (ELISA), Western blot, and transmission electron microscopy (TEM) confirmed ␣-enolase on the cell surface as well as in the cytoplasm of S. mutans. Results of Western blot, TEM, and ELISA experiments demonstrate that S. mutans surface enolase binds to human plasminogen and human salivary mucin MG2.S. mutans A32-2 was isolated from a highly-caries-active patient and expresses significantly more surface proteins than isolates from caries-free subjects (26). Surface protein, cell wall, and cytoplasmic samples were purified according to methods ...

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Section: Fig 4 Ability Of S Mutansmentioning

confidence: 69%

mentioning

confidence: 99%

Streptococcus mutans Surface α-Enolase Binds Salivary Mucin MG2 and Human Plasminogen

Ge¹,

Catt

Gregory

2004

Infect Immun

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“…The N-terminal part of the polypeptide chain of MUC7 has also been implicated in the binding to bacteria 21 and this region has been shown to have Candidacidal activity. 31,32 A search for possible functional polymorphism in this region, or elsewhere in the gene, such as a promoter element would be worthwhile.…”

Section: Muc7 Polymorphismmentioning

confidence: 99%

“…5 It is thought to function in a protective capacity by promoting the clearance of bacteria in the oral cavity and to aid in mastication, speech and swallowing. 19 ± 21 It has been shown to interact with a variety of bacteria, including four strains of streptococci, 21 Actinobacillus actinomycetemcomitans, 22 Staphylococcus aureus and Pseudomonas aeruginosa. 18 MUC7 has been shown to be expressed in the bronchial tree as well as in the salivary glands.…”

Section: Introductionmentioning

confidence: 99%

Genetic polymorphism of MUC7: Allele frequencies and association with asthma

et al. 2001

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MUC7 encodes a small salivary mucin, previously called MG2, a glycoprotein with a putative role in facilitating the clearance of oral bacteria. The central domain of this glycoprotein was previously shown to comprise five or six tandemly repeated units of 23 amino-acids which carry most of the O-linked glycans. The polymorphism of these two allelic forms (MUC7*5 or MUC7*6) has been confirmed in this study in which we have analysed a large cohort of subjects (n = 375) of various ethnic origins. We have also identified a novel rare allele with eight tandem repeats (MUC7*8). MUC7*6 was the most common allele (0.78 ± 0.95) in all the populations tested. The tandem repeat arrays of 22 MUC7*5 alleles and 34 MUC7*6 alleles were sequenced. No sequence differences were detected in any of the MUC7*6 alleles. Twenty-one MUC7*5 alleles sequenced lacked the 4th tandem repeat (structure TR12356), while one showed the structure TR12127. The structure of the MUC7*8 allele was TR12343456. Because of the known role of MUC7 in bacterial binding, and thus its potential involvement in susceptibility to chest disease we also tested MUC7 in our previously described series of Northern European atopic individuals with and without associated asthma. The MUC7*5 allele was rarer in the atopic asthmatics than in the atopic non-asthmatics (P = 0.014, OR for no asthma in atopic individuals 3.13, CI 1.01 ± 6.10), and the difference in frequency between all asthmatics and all non-asthmatics was statistically significant (P = 0.009) while there was no difference between atopy and non-atopy (P = 0.199). In this study we also report the electrophoretic analysis of the MUC7 glycoprotein in saliva from individuals of different MUC7 genotype.

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“…A recent report has shown that cell adhesion of Pseudomonas aeruginosa, a Gram-negative bacterium, was enhanced by the presence of MUC1 on the cell surface (43). MUC7 has been shown to interact with a variety of bacteria including four strains of Streptococci (44), Actinobacillus actinomycetemcomitans (45), Staphylococcus aureus, and P. aeruginosa (46), and it may have a role in facilitating the clearance of oral bacteria. Moreover, two sulfate mucin-type glycoproteins on lymph node endothelium were found to bind lymphocyte L-selectin (47,48), whereas sialylated and fucosylated mucin-types were shown to bind P-selectin (49,50).…”

Section: Figmentioning

confidence: 99%

Molecular Cloning, Genomic Structure, and Expression Analysis of MUC20, a Novel Mucin Protein, Up-regulated in Injured Kidney

Higuchi

Orita

Nakanishi

et al. 2004

Journal of Biological Chemistry

124

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Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis in the world. Here, we identify a cDNA encoding a novel mucin protein, shown previously to be up-regulated in IgAN patients, from a human kidney cDNA library. This protein contains a mucin tandem repeat of 19 amino acids consisting of many threonine, serine, and proline residues and likely to be extensively O-glycosylated; thus, this gene was classified in the mucin family and named MUC20. The human MUC20 gene contains at least four exons and is localized close to MUC4 on chromosome 3q29. We found variations in repeat numbers in the mucin tandem domain, suggesting polymorphism of this region. Northern blot and reverse transcription-PCR analyses revealed that human MUC20 mRNA was expressed most highly in kidney and moderately in placenta, colon, lung, prostate, and liver. Immunohistochemical analysis of human kidney revealed that MUC20 protein was localized in the proximal tubules. Immunoblotting analysis of MUC20 proteins produced in Madin-Darby canine kidney and HEK293 cells indicated the localization of MUC20 protein in a membrane fraction and extensive posttranslational modification. Immunoelectron microscopy of MUC20-producing Madin-Darby canine kidney cells demonstrated that MUC20 protein was localized on the plasma membrane. Expression of MUC20 mRNA in a human kidney cell line was up-regulated by tumor necrosis factor-␣, phorbol 12-myristate 13-acetate, or lipopolysaccharide. Two species of MUC20 mRNA (hMUC20-L and hMUC20-S), resulting from alternative transcription, were identified in human tissue, whereas only one variant was observed in mouse tissues. Mouse MUC20 mRNA was expressed in the epithelial cells of proximal tubules, and the expression increased dramatically with the progression of lupus nephritis in the kidney of MRL/MpJ-lpr/lpr mice.Moreover, the expression of mouse MUC20 was augmented in renal tissues acutely injured by cisplatin or unilateral ureteral obstruction. These characteristics suggest that the production of MUC20 is correlated with development and progression of IgAN and other renal injuries.

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Isolation of Human Salivary Mucin MG2 by a Novel Method and Characterization of Its Interactions with Oral Bacteria

Cited by 54 publications

References 27 publications

Streptococcus mutans Surface α-Enolase Binds Salivary Mucin MG2 and Human Plasminogen

Streptococcus mutans Surface α-Enolase Binds Salivary Mucin MG2 and Human Plasminogen

Genetic polymorphism of MUC7: Allele frequencies and association with asthma

Molecular Cloning, Genomic Structure, and Expression Analysis of MUC20, a Novel Mucin Protein, Up-regulated in Injured Kidney

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