Human porimin (pro-oncosis receptor inducing membrane injury) is a type I transmembrane glycoprotein that belongs to the cell membrane-associated mucin family. The extracellular domain is composed of 45% serine and threonine residues and has multiple N- and O-linked glycosylation sites. The cytoplasmic tail contains a lysosome-targeting motif. Porimin is ubiquitously expressed and its activation induces cell death.