Major keratinocyte cell envelope protein. Expressed in the epidermis of the ear (at protein level). Expressed in the spinous and granular layers of the tongue at P20. Substrate of transglutaminases. Some glutamines and lysines are cross-linked to other loricrin molecules and to SPRRs proteins. Contains inter- or intramolecular disulfide-bonds. Transgenic mice expressing a C-terminal truncated form of loricrin exhibited, at birth, erythrokeratoderma with an epidermal barrier dysfunction. 4 days after birth, high-expressing transgenic animals showed a generalized scaling of the skin, as well as a constricting band encircling the tail and, by day 7, a thickening of the footpads. Transgenic mice also showed retention of nuclei in the stratum corneum. The mutant loricrin protein is found in the nucleus and cytoplasm of epidermal keratinocytes, but is not detect in the cornified cell envelope. The C-terminal domain of the mutant loricrin contains a nuclear localization signal.