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. {ECO:0000269|PubMed:11445004, ECO:0000269|PubMed:11842292, ECO:0000269|PubMed:11956057, ECO:0000269|PubMed:23112050, ECO:0000269|PubMed:9828122}. This is the function of ENSG00000016490 (CLCA1, chloride channel accessory 1).