Predicted to enable calcium ion binding activity. Acts upstream of or within several processes, including circulatory system development; endothelial cell morphogenesis; and lymph circulation. Located in cell-cell junction and external side of plasma membrane. Is expressed in several structures, including alimentary system; brain; cardiovascular system; genitourinary system; and immune system. Orthologous to human HEG1 (heart development protein with EGF like domains 1). [provided by Alliance of Genome Resources, Apr 2022]