Cross-linked envelope protein of keratinocytes. It is a keratinocyte protein that first appears in the cell cytosol, but ultimately becomes cross-linked to membrane proteins by transglutaminase. All that results in the formation of an insoluble envelope beneath the plasma membrane (By similarity). Not expressed in uterus. Belongs to the cornifin (SPRR) family. Defined as a pseudogene by MGI. Compared to other members of the family it contains a frameshift in position 20. However, proteomics data suggest the existence of the protein.