May act as a soluble regulator of keratinocyte differentiation. Homooligomer. Seems to be able to homodimerize and homotrimerize. Expressed in epidermis; in the spinous and granular layers and in placenta. Also found in the epithelia of the small intestine, macrophages of the lung and endothelial cells of the lung. Isoform 15 is expressed in epidermis and placenta. Isoform 1 is expressed in epidermis. O-glycosylated. Belongs to the dermokine family.