Predicted to enable chloride channel activity. Involved in circadian rhythm; female pregnancy; and response to progesterone. Located in several cellular components, including apicolateral plasma membrane; basal plasma membrane; and lateral plasma membrane. Biomarker of peptic esophagitis. Human ortholog(s) of this gene implicated in ovarian cancer and pancreatic cancer. Orthologous to human CLDN4 (claudin 4). [provided by Alliance of Genome Resources, Apr 2022]