Profilaggrin is a large, insoluble, highly phosphorylated precursor protein and major component of keratohyalin granules in the living cells of the epidermis. During terminal differentiation of the epidermis, profilaggrin is proteolytically processed into active Filaggrin molecules that promote aggregation and disulfide-bond formation of keratin intermediate filaments. Active Filaggrin is present at a level of the epidermis where keratinocytes are in transition between the live nucleated granular layer and the anucleate cornified layer, suggesting that Filaggrin aids in the terminal differentiation process by facilitating apoptotic machinery. Filaggrin 2, also known as FLG2, Ifapsoriasin or IFPS (intermediate filament-associated and psoriasis-susceptibility protein), is a 2,391 amino acid protein that shares common structural features with Filaggrin. Filaggrin 2 contains ten Filaggrin repeats, two EF-hand domains and belongs to both the S-100 and S100-fused protein families.