Probable chaperone protein for the phospholipid-transporting ATPase tat-1. Regulates cell membrane structure and function. Plays a role in maintaining the membrane phosphatidylserine asymmetry and the formation of the tubular membrane structure. Involved in membrane trafficking and is specifically involved in the recycling and degradation of endocytic cargo and this is likely with the phospholipid-transporting ATPase tat-1. Colocalizes with phospholipid-transporting ATPase tat-1 at apical and basolateral cell membranes, on early endosomes and on recycling endosomes. Also localizes to intracellular tubular and vesicular structures. Expressed from early embryogenesis to adulthood in various cell types. RNAi-mediated knockdown results in the appearance of abnormal vacuoles in the intestines and defective recycling of endocytic cargo with the accumulation of cargo within abnormal early endosomes. Belongs to the CDC50/LEM3 family.