[5][6] In binding the protein loricrin, involucrin contributes to the formation of a cell envelope that protects corneocytes in the skin.

[6] Involucrin is a highly reactive, soluble, transglutaminase substrate protein present in keratinocytes of epidermis and other stratified squamous epithelia.

[citation needed] Apigenin, a plant-derived flavanoid that has significant promise as a skin cancer chemopreventive agent, has been found to regulate normal human keratinocyte differentiation by suppressing involucrin, and this is associated with reduced cell proliferation without apoptosis.

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] Involucrin consists of a conserved N-terminal region of about 75 amino acid residues followed by two extremely variable length segments that contain glutamine-rich tandem repeats.