May be involved in mediating calcium-activated chloride conductance (PubMed:8537359). 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. Trachea. The metalloprotease region is responsible for autoproteolytic processing. It can also cross-cleave other CLCA substrates. Glycosylated. The 125-kDa product is autoproteolytically processed by the metalloprotease domain and yields to two cell-surface-associated subunits, a 90-kDa protein and a group of 37- to 41-kDa proteins. The cleavage is necessary for calcium-activated chloride channel (CaCC) activation activity. Belongs to the CLCR family. Was initially characterized as chloride channel, but such a function is difficult to reconcile with the single predicted transmembrane region. Other family members have been shown to stimulate channel activity.