May be involved in mediating calcium-activated chloride conductance. May play critical roles in goblet cell metaplasia, mucus hypersecretion, cystic fibrosis and AHR. May be involved in the regulation of mucus production and/or secretion by goblet cells. Involved in the regulation of tissue inflammation in the innate immune response. May play a role as a tumor suppressor. Induces MUC5AC (By similarity). Expressed in mucin-producing cells in the respiratory and intestinal tracts, cutaneous sweat glands, and renal mucous glands (at protein level). Strong overexpression in the airways of horses with recurrent airway obstruction (at protein level). Strongly up-regulated in bronchioles with recurrent airway obstruction (RAO). The metalloprotease region is responsible for autoproteolytic processing. It can also cross-cleave other CLCA substrates. Glycosylated. The translation product is autoproteolytically cleaved by the metalloprotease domain in the endoplasmic reticulum into a N-terminal and a C-terminal products that remain physically associated with each other. The cleavage is necessary for calcium-activated chloride channel (CaCC) activation activity. Belongs to the CLCR family.