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). 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.