Involved in embryonic dorsal-ventral patterning which is generated by a series of serine protease processing events where gd processes snk which cleaves ea which then processes spz into the activating ligand for the Toll receptor. Required during this process for the secretion of ea from the developing embryo into the perivitelline space and for ea processing. Expressed in blastoderm embryos (at protein level). Abundantly expressed in late-stage embryos including in the developing salivary glands (at protein level). Formation of embryos with altered dorsal-ventral patterning, dramatically decreased levels of ea in the perivitelline space and reduced processing of ea. Belongs to the canopy family.