Involucrin is a protein component of human skin and in humans is encoded by the IVLgene.[5][6] In binding the protein loricrin, involucrin contributes to the formation of a cell envelope that protects corneocytes in the skin.
Involucrin is synthesised in the stratum spinosum and cross linked in the stratum granulosum by the transglutaminase enzyme that makes it highly stable. Thus it provides structural support to the cell, thereby allowing the cell to resist invasion by micro-organisms.[citation needed]
As one of the precursor proteins of the cornified cell envelope, involucrin is markedly increased in inflammatory skin diseases such as psoriasis[11]
Lamellar ichthyosis involves a decrease in expression of involucrin. This decrease could contribute to the altered desquamation process seen in the disease, since the clinical improvement associated with retinoid treatment is accompanied by increased expression of involucrin.[12]
Structure
Involucrin consists of a conservedN-terminal region of about 75 amino acid residues followed by two extremely variable length segments that contain glutamine-rich tandem repeats. The glutamine residues in the tandem repeats are the substrate for the transglutaminase in the cross-linking reaction. The total size of the protein varies from 285 residues (in dog) to 835 residues (in orangutan).[citation needed]
^Takahashi H, Hashimoto Y, Ishida-Yamamoto A, Iizuka H (September 2005). "Roxithromycin suppresses involucrin expression by modulation of activator protein-1 and nuclear factor-kappaB activities of keratinocytes". Journal of Dermatological Science. 39 (3): 175–82. doi:10.1016/j.jdermsci.2005.03.006. PMID16140218.
Eckert RL, Crish JF, Efimova T, Dashti SR, Deucher A, Bone F, Adhikary G, Huang G, Gopalakrishnan R, Balasubramanian S (July 2004). "Regulation of involucrin gene expression". The Journal of Investigative Dermatology. 123 (1): 13–22. doi:10.1111/j.0022-202X.2004.22723.x. PMID15191537.
Rice RH, Green H (November 1979). "Presence in human epidermal cells of a soluble protein precursor of the cross-linked envelope: activation of the cross-linking by calcium ions". Cell. 18 (3): 681–94. doi:10.1016/0092-8674(79)90123-5. PMID42494.
Volz A, Korge BP, Compton JG, Ziegler A, Steinert PM, Mischke D (October 1993). "Physical mapping of a functional cluster of epidermal differentiation genes on chromosome 1q21". Genomics. 18 (1): 92–9. doi:10.1006/geno.1993.1430. PMID8276421.
Ng DC, Su MJ, Kim R, Bikle DD (January 1996). "Regulation of involucrin gene expression by calcium in normal human keratinocytes". Frontiers in Bioscience. 1: a16-24. doi:10.2741/A101. PMID9159190.
Lee CH, Marekov LN, Kim S, Brahim JS, Park MH, Steinert PM (July 2000). "Small proline-rich protein 1 is the major component of the cell envelope of normal human oral keratinocytes". FEBS Letters. 477 (3): 268–72. doi:10.1016/S0014-5793(00)01806-8. PMID10908733.