Mucin-5B (MUC-5B) is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

that in humans is encoded by the ''MUC5B''

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

and by the ''Muc5b''

in the mouse. It is one of the five gel-forming

mucins Mucins () are a family of high molecular weight, heavily glycosylation, glycosylated proteins (glycoconjugates) produced by epithelial tissues in most animals. Mucins' key characteristic is their ability to form gels; therefore they are a key com ...

. MUC-5B can be found in whole saliva, normal lung mucus, and cervical mucus. In some diseases, such as

COPD Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by chronic respiratory symptoms and airflow limitation. GOLD defines COPD as a heterogeneous lung condition characterized by chronic respiratory s ...

, 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.

Synthesis

All mucins are synthesized in secretory cells known as

goblet cell Goblet cells are simple columnar epithelial cells that secrete gel-forming mucins, like mucin 2 in the lower gastrointestinal tract, and mucin 5AC in the respiratory tract. The goblet cells mainly use the merocrine method of secretion, secre ...

s 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.

References

05B {{protein-stub