Mucin 5B
{{Short description|Protein-coding gene in the species Homo sapiens}}
{{Infobox_gene}}
Mucin-5B (MUC-5B) is a protein that in humans is encoded by the MUC5B gene
{{cite journal | vauthors = Desseyn JL, Buisine MP, Porchet N, Aubert JP, Laine A | title = Genomic organization of the human mucin gene MUC5B. cDNA and genomic sequences upstream of the large central exon | journal = The Journal of Biological Chemistry | volume = 273 | issue = 46 | pages = 30157–64 | date = November 1998 | pmid = 9804771 | doi = 10.1074/jbc.273.46.30157 | doi-access = free }}{{cite journal | vauthors = Desseyn JL, Guyonnet-Dupérat V, Porchet N, Aubert JP, Laine A | title = Human mucin gene MUC5B, the 10.7-kb large central exon encodes various alternate subdomains resulting in a super-repeat. Structural evidence for a 11p15.5 gene family | journal = The Journal of Biological Chemistry | volume = 272 | issue = 4 | pages = 3168–78 | date = November 1997 | pmid = 9013550 | doi = 10.1074/jbc.272.6.3168 | doi-access = free }}{{cite journal | vauthors = Desseyn JL, Aubert JP, Van Seuningen I, Porchet N, Laine A | title = Genomic organization of the 3' region of the human mucin gene MUC5B | journal = The Journal of Biological Chemistry | volume = 272 | issue = 27 | pages = 16873–83 | date = 1997 | pmid = 9201995 | doi = 10.1074/jbc.272.27.16873 | doi-access = free }}{{cite web |title=Entrez Gene: MUC5B mucin 5B, oligomeric mucus/gel-forming| url=https://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=727897}} and by the Muc5b gene in the mouse. It is one of the five gel-forming mucins. MUC-5B can be found in whole saliva, normal lung mucus, and cervical mucus. In some diseases, such as COPD, chronic rhinosinusitis (CRS), and H. pylori-associated gastric disease, the gene has been found to be upregulated, and this may be related to the pathogenesis of these conditions.{{Cite web|title=MUC5B mucin 5B, oligomeric mucus/gel-forming [Homo sapiens (human)] - Gene - NCBI|url=https://www.ncbi.nlm.nih.gov/gene/727897|access-date=2021-06-10|website=www.ncbi.nlm.nih.gov}}
Synthesis
All mucins are synthesized in secretory cells known as goblet cells or mucous cells, depending on the tissue location. Their creation, while still not completely understood, begins in the endoplasmic reticulum. From there, the Golgi apparatus builds the O-linked glycans found in mucins. Finally, they are packaged into secretory granules.{{cite book | vauthors = McGuckin MA, Thornton DJ, Whitsett JA | chapter = Mucins and mucus. | title = Mucosal Immunology | date = January 2015 | pages = 231–250 | publisher = Academic Press | doi = 10.1016/B978-0-12-415847-4.00014-8 | isbn = 9780124158474 }}