Involucrin (IVL)

Involucrin is a structural protein encoded by the IVL gene located on chromosome 1q21. It is a soluble, highly reactive substrate for transglutaminase enzymes found primarily in keratinocytes of the epidermis and other stratified squamous epithelia. During terminal differentiation, involucrin becomes cross-linked to membrane proteins beneath the plasma membrane to form an insoluble cornified cell envelope that provides mechanical strength and resistance to microbial invasion. The protein consists of a conserved N-terminal region followed by variable glutamine-rich tandem repeats that serve as substrates for cross-linking. Involucrin synthesis begins in the stratum spinosum layer of the epidermis; it is then incorporated into the cornified envelope during progression through the stratum granulosum. Clinically, altered levels are observed in several skin disorders—upregulated in inflammatory conditions like psoriasis and downregulated in lamellar ichthyosis—making it useful as a biomarker for certain dermatological states but not currently considered a direct therapeutic target or receptor.

Other names

IVLINVO proteinInvolucrum protein (rare, from etymology)