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Degradation of MUC7 and MUC5B in Human Saliva
BACKGROUND: Two types of mucins, MUC7 and MUC5B constitute the major salivary glycoproteins, however their metabolic turnover has not been elucidated in detail to date. This study was conducted to examine turnover of MUC7 and MUC5B in saliva, by focusing on the relationship between their deglycosyla...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3715446/ https://www.ncbi.nlm.nih.gov/pubmed/23874867 http://dx.doi.org/10.1371/journal.pone.0069059 |
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author | Takehara, Sachiko Yanagishita, Masaki Podyma-Inoue, Katarzyna Anna Kawaguchi, Yoko |
author_facet | Takehara, Sachiko Yanagishita, Masaki Podyma-Inoue, Katarzyna Anna Kawaguchi, Yoko |
author_sort | Takehara, Sachiko |
collection | PubMed |
description | BACKGROUND: Two types of mucins, MUC7 and MUC5B constitute the major salivary glycoproteins, however their metabolic turnover has not been elucidated in detail to date. This study was conducted to examine turnover of MUC7 and MUC5B in saliva, by focusing on the relationship between their deglycosylation and proteolysis. METHODOLOGY/PRINCIPAL FINDINGS: Whole saliva samples were collected from healthy individuals and incubated at 37°C in the presence of various protease inhibitors, sialidase, or a sialidase inhibitor. General degradation patterns of salivary proteins and glycoproteins were examined by SDS-polyacrylamide-gel-electrophoresis. Furthermore, changes of molecular sizes of MUC7 and MUC5B were examined by Western blot analysis. A protein band was identified as MUC7 by Western blot analysis using an antibody recognizing an N-terminal epitope. The MUC7 signal disappeared rapidly after 20-minutes of incubation. In contrast, the band of MUC7 stained for its carbohydrate components remained visible near its original position for a longer time indicating that the rapid loss of Western blot signal was due to the specific removal of the N-termimal epitope. Pretreatment of saliva with sialidase facilitated MUC7 protein degradation when compared with samples without treatment. Furthermore, addition of sialidase inhibitor to saliva prevented proteolysis of N-terminus of MUC7, suggesting that the desialylation is a prerequisite for the degradation of the N-terminal region of MUC7. The protein band corresponding to MUC5B detected in both Western blotting and glycoprotein staining showed little sign of significant degradation upon incubation in saliva up to 9 hours. CONCLUSIONS/SIGNIFICANCE: MUC7 was highly susceptible to specific proteolysis in saliva, though major part of MUC5B was more resistant to degradation. The N-terminal region of MUC7, particularly sensitive to proteolytic degradation, has also been proposed to have distinct biological function such as antibacterial activities. Quick removal of this region may have biologically important implication. |
format | Online Article Text |
id | pubmed-3715446 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-37154462013-07-19 Degradation of MUC7 and MUC5B in Human Saliva Takehara, Sachiko Yanagishita, Masaki Podyma-Inoue, Katarzyna Anna Kawaguchi, Yoko PLoS One Research Article BACKGROUND: Two types of mucins, MUC7 and MUC5B constitute the major salivary glycoproteins, however their metabolic turnover has not been elucidated in detail to date. This study was conducted to examine turnover of MUC7 and MUC5B in saliva, by focusing on the relationship between their deglycosylation and proteolysis. METHODOLOGY/PRINCIPAL FINDINGS: Whole saliva samples were collected from healthy individuals and incubated at 37°C in the presence of various protease inhibitors, sialidase, or a sialidase inhibitor. General degradation patterns of salivary proteins and glycoproteins were examined by SDS-polyacrylamide-gel-electrophoresis. Furthermore, changes of molecular sizes of MUC7 and MUC5B were examined by Western blot analysis. A protein band was identified as MUC7 by Western blot analysis using an antibody recognizing an N-terminal epitope. The MUC7 signal disappeared rapidly after 20-minutes of incubation. In contrast, the band of MUC7 stained for its carbohydrate components remained visible near its original position for a longer time indicating that the rapid loss of Western blot signal was due to the specific removal of the N-termimal epitope. Pretreatment of saliva with sialidase facilitated MUC7 protein degradation when compared with samples without treatment. Furthermore, addition of sialidase inhibitor to saliva prevented proteolysis of N-terminus of MUC7, suggesting that the desialylation is a prerequisite for the degradation of the N-terminal region of MUC7. The protein band corresponding to MUC5B detected in both Western blotting and glycoprotein staining showed little sign of significant degradation upon incubation in saliva up to 9 hours. CONCLUSIONS/SIGNIFICANCE: MUC7 was highly susceptible to specific proteolysis in saliva, though major part of MUC5B was more resistant to degradation. The N-terminal region of MUC7, particularly sensitive to proteolytic degradation, has also been proposed to have distinct biological function such as antibacterial activities. Quick removal of this region may have biologically important implication. Public Library of Science 2013-07-18 /pmc/articles/PMC3715446/ /pubmed/23874867 http://dx.doi.org/10.1371/journal.pone.0069059 Text en © 2013 Takehara et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Takehara, Sachiko Yanagishita, Masaki Podyma-Inoue, Katarzyna Anna Kawaguchi, Yoko Degradation of MUC7 and MUC5B in Human Saliva |
title | Degradation of MUC7 and MUC5B in Human Saliva |
title_full | Degradation of MUC7 and MUC5B in Human Saliva |
title_fullStr | Degradation of MUC7 and MUC5B in Human Saliva |
title_full_unstemmed | Degradation of MUC7 and MUC5B in Human Saliva |
title_short | Degradation of MUC7 and MUC5B in Human Saliva |
title_sort | degradation of muc7 and muc5b in human saliva |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3715446/ https://www.ncbi.nlm.nih.gov/pubmed/23874867 http://dx.doi.org/10.1371/journal.pone.0069059 |
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