Ca(2+) sensor involved in Ca(2+)-dependent secretion of the nlp-40 neuropeptide from intestinal cells. Involved in the defecation motor program, which is a coordinated series of three muscle contractions that occurs every 45 seconds. Binds 3 Ca(2+) ions per C2 domain. Co-localizes with nlp-40 in cytoplasmic vesicles. Expressed throughout the intestine and in several neurons in the head and tail. Defecation abnormalities. Belongs to the synaptotagmin family.