Cornifin-B is a protein that in humans is encoded by the SPRR1B gene. 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. Can function as both amine donor and acceptor in transglutaminase-mediated cross-linkage.