Enables calcium channel regulator activity and identical protein binding activity. Involved in several processes, including ovulation; positive regulation of engulfment of apoptotic cell; and store-operated calcium entry. Located in cytoplasm; plasma membrane; and somatodendritic compartment. Expressed in gonadal sheath cell; intestine; spermatheca; and uterine toroidal epithelial cell. Human ortholog(s) of this gene implicated in several diseases, including Stormorken syndrome; gastrointestinal system cancer (multiple); and immunodeficiency 10. Is an ortholog of human STIM1 (stromal interaction molecule 1).