Recombinant Human Mucin-5B (MUC5B), partial

Function

Gel-forming mucin that is thought to contribute to the lubricating and viscoelastic properties of whole saliva and cervical mucus

Subcellular Location

Secreted

Disease Association

Interstitial lung disease 2 (ILD2) : A form of interstitial lung disease, a heterogeneous group of diseases affecting the distal part of the lung and characterized by a progressive remodeling of the alveolar interstitium. The disease spectrum ranges from idiopathic interstitial pneumonia or pneumonitis to idiopathic pulmonary fibrosis, that is associated with an increased risk of developing lung cancer. Clinical features of interstitial lung disease include dyspnea, clubbing of the fingers, and restrictive lung capacity. ILD2 inheritance is autosomal dominant. [Disease susceptibility is associated with variants affecting the gene represented in this entry. A common polymorphism in the promoter of MUC5B is associated with familial interstitial pneumonia and idiopathic pulmonary fibrosis, suggesting that dysregulated MUC5B expression in the lung may be involved in the pathogenesis of pulmonary fibrosis (PubMed:21506741)]

Tissue Specificity

Expressed on surface airway epithelia. Expressed mainly in mucous cells of submucosal glands of airway tissues. Highly expressed in the sublingual gland. Also found in submaxillary glands, endocervix, gall bladder, and pancreas

Subunit

Homomultimer; disulfide-linked (PubMed:31570524). The N- and C-terminus mediate their assembly into higher order structures to form filaments (By similarity). The CTCK domains of two polypeptides associate in the endoplasmic reticulum to generate intermolecularly disulfide-bonded dimers (PubMed:31570524). These dimers progress to the Golgi apparatus, which is a more acidic environment than the endoplasmic reticulum (By similarity). Under acidic conditions, the N-termini form non-covalent intermolecular interactions that juxtapose assemblies from different CTCK-linked dimers to produce long, disulfide-linked polymers that remain highly compact until secretion (By similarity)

• Chen Y. et al. Characterization of human mucin 5B gene expression in airway epithelium and the genomic clone of the amino-terminal and 5'-flanking region. — Am. J. Respir. Cell Mol. Biol. (2001)
• Offner G.D. et al. The amino-terminal sequence of MUC5B contains conserved multifunctional D domains: implications for tissue-specific mucin functions. — Biochem. Biophys. Res. Commun. (1998)
• Desseyn J.-L. et al. Genomic organization of the human mucin gene MUC5B: cDNA and genomic sequences upstream of the large central exon. — J. Biol. Chem. (1998)
• Desseyn J.-L. et al. 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. — J. Biol. Chem. (1997)
• Rose M.C. et al. Proteolytic fragmentation and peptide mapping of human carboxyamidomethylated tracheobronchial mucin. — J. Biol. Chem. (1989)
• Nielsen P.A. et al. Identification of a major human high molecular weight salivary mucin (MG1) as tracheobronchial mucin MUC5B. — Glycobiology (1997)
• Keates A.C. et al. Molecular cloning of a major human gall bladder mucin: complete C-terminal sequence and genomic organization of MUC5B. — Biochem. J. (1997)
• Troxler R.F. et al. Molecular cloning of a novel high molecular weight mucin (MG1) from human sublingual gland. — Biochem. Biophys. Res. Commun. (1995)