Involved in the cornified cell envelope formation. Multifunctional epidermal matrix protein. Detectable in the stratified internal epithelia of forestomach and tongue and to a lesser degree in normal skin epidermis, where it is restricted to the differentiated suprabasal cell layers. Overexpressed in skin tumors. Expressed during late differentiation of the epidermis. Can be divided into a N-terminal domain with significant homology to S100-like calcium-binding proteins, a central domain containing a series of short tandem repeats, and two flanking segments with low homology to the consensus sequences of the central repeats. Potential substrate of transglutaminase. Some arginines are probably converted to citrullines by peptidylarginine deimidase. Belongs to the S100-fused protein family.