Mucin 5AC (MUC5AC) and Mucin 5B (MUC5B) (MUC5AC, MUC5B)

Airway mucus is the first physiological barrier in the respiratory tract, protecting against inhaled pathogens and particles. Its primary macromolecular components are the secreted, gel-forming mucins MUC5AC and MUC5B, which determine the viscoelastic and barrier properties of mucus[2][1][4]. MUC5B is dominant in healthy mucus transport, whereas changes in amount or ratio of MUC5AC/MUC5B are implicated in disease[4]. These mucins are large, heavily O-glycosylated glycoproteins that form extensive polymers, regulating mucus hydration and structure. Overproduction or biophysical alteration of these mucins is central to airway diseases such as asthma, cystic fibrosis, and COPD, making them important therapeutic targets. The interaction of mucus with drugs, nanoparticles, and pathogens is governed by mucin polymer properties, glycosylation patterns, and concentrations[1][3][5]. Mucopolysaccharides as a generic class are not the primary structural or functional entities in airway mucus, except as minor glycosaminoglycan components within the mucin matrix[5].

Other names

Airway mucinsgel-forming mucinsrespiratory tract mucins

Mucolysis (enzymatic or chemical degradation of mucus polymers); Inhibition of mucin gene expression or secretion; Hydration and physical thinning of mucus gel