Homophilic transmembrane adhesion molecule involved in non-apoptotic necrotic cell death (PubMed:23028562). Promotes cell adhesion by mediating homophilic interactions via its extracellular region (By similarity). Probably involved in non-apoptotic necrotic cell death by mediating plasma membrane rupture (cytolysis), leading to release intracellular molecules that propagate the inflammatory response (PubMed:33472215). Secreted form generated by cleavage, which acts as a negative regulator of cell adhesion (PubMed:16815999). Promotes the loss of cell adhesion in a cell non-autonomous manner (PubMed:16815999). Homooligomer. Up-regulated upon injury. Cleaved by Mmp1 protease to generate the Secreted ninjurin-A form. No visible phenotype; flies are viable and fertile with no obvious developmental abnormalities. Belongs to the ninjurin family.