Involved in pharynx morphogenesis probably by remodeling the basement membrane. Plays a role in embryogenesis, the second phase of distal cell tip migration and is required for distribution of the metalloproteinase, mig-17, during organogenesis. Plays a role in post embryonic distal cell tip migration (PubMed:19297413). Essential extracellular matrix (ECM) protein required for hypodermal enclosure in the embryo (PubMed:11076767). Localizes to the basement membranes of the gonad primordium, pharynx and intestine (at protein level) (PubMed:19297413). Expressed in head and CAN neurons, coelomocytes, body-wall muscles and anal depressor and sphincter and stomatointestinal muscles (PubMed:19297413, PubMed:20805556). Expressed Isoform a: is expressed in body wall muscles and distal cell tips (PubMed:19297413). Isoform b: expressed in embryonic muscles (PubMed:19297413). Expression is first detected is intestinal primordium at the E16 embryonic stage followed by expression in future head neurons and head muscle cells at the comma and 1.5-fold stages (PubMed:20805556). Expressed in larvae and adults (PubMed:19297413, PubMed:20805556). Belongs to the papilin family.