Cornified envelope protein (CE protein)

The cornified envelope (CE) is a specialized, highly insoluble protein-lipid structure that replaces the plasma membrane of keratinocytes during terminal differentiation in the epidermis [StatPearls]. It is composed of several key proteins, including loricrin, involucrin, filaggrin, and small proline-rich proteins, which are cross-linked by transglutaminase enzymes to provide a robust mechanical and permeability barrier [PubMed]. These proteins are essential for maintaining skin hydration and protecting against environmental stressors and pathogens [NIH]. Deficiencies or mutations in these proteins, particularly filaggrin, are central to the pathogenesis of various skin disorders, such as atopic dermatitis, psoriasis, and ichthyosis [PubMed]. In inflammatory skin diseases, cytokines like IL-4 and IL-13 can downregulate the expression of these barrier proteins, further compromising the skin's integrity [Journal of Investigative Dermatology]. Therapeutic strategies often focus on restoring the expression of these proteins to repair the skin barrier. For example, tapinarof acts as an aryl hydrocarbon receptor (AhR) agonist to induce the expression of filaggrin and involucrin [PubMed]. Biologics like dupilumab indirectly support the cornified envelope by blocking the Th2 cytokines that suppress its formation. Consequently, cornified envelope proteins serve as critical functional targets for both topical and systemic dermatological treatments aimed at repairing the skin's protective shield.

Other names

Cornified cell envelope proteinsKeratinocyte envelope proteinsEpidermal barrier proteinsLoricrinInvolucrinFilaggrinSmall proline-rich proteinsLate cornified envelope proteins

Upregulation of barrier protein expression via Aryl hydrocarbon receptor (AhR) activation; inhibition of Th2-mediated suppression of barrier protein synthesis.