May insert into membranes and form chloride ion channels. Involved in the formation of the excretory canal. Required to prevent cystic lumenal expansions in the excretory cell. Not required for formation of the initial tube, but is required for regulating the size of the tube lumen as it grows. Monomer. Exists both as soluble cytoplasmic protein and as membrane protein with probably a single transmembrane domain. Localizes to various tubular membranes in distinct cell types, including the lumenal membrane of the excretory tubes. Expressed in the secretory system, hypodermis, vulva, pharyngeal muscle, rectal gland, tubular rectal epithelium cells, and tubular neuronal support cells in the head and tail. The N-terminal part (1-55) is necessary and sufficient for translocation from the cytosol to the membrane. Members of this family may change from a globular, soluble state to a state where the N-terminal domain is inserted into the membrane and functions as chloride channel. A conformation change of the N-terminal domain is thought to expose hydrophobic surfaces that trigger membrane insertion (By similarity). Belongs to the chloride channel CLIC family.