Keratin and corneocyte proteins (KRT/CE proteins)

Keratins and corneocyte proteins are the primary structural components of the epidermis, specifically the stratum corneum. Keratins are a large family of intermediate filament proteins (Type I and Type II) that provide mechanical resilience and structural integrity to epithelial cells (UniProt, 2023). Corneocyte proteins, including filaggrin, loricrin, and involucrin, are essential for the formation of the cornified envelope, a highly insoluble barrier that protects against environmental insults and prevents transepidermal water loss (PubMed, PMID: 22403314). In dermatological conditions such as psoriasis, ichthyosis, and acne, there is often an overproduction or abnormal organization of these proteins, leading to hyperkeratosis and barrier dysfunction (NCBI, NBK470421). Therapeutic intervention targeting these proteins typically involves the use of keratolytic agents and retinoids. Keratolytics, such as salicylic acid and urea, work by increasing the moisture content of the skin and softening the keratin, which facilitates the shedding of the stratum corneum (StatPearls, 2023). Retinoids, on the other hand, act as ligands for nuclear receptors that regulate the expression of specific keratin genes, thereby normalizing the differentiation process of keratinocytes. While effective, treatments affecting these structural proteins can lead to side effects such as skin irritation and increased sensitivity to UV radiation due to the thinning of the protective outer layer.

Other names

CytokeratinsCornified envelope proteinsKeratin filamentsIntermediate filament proteinsEpidermal structural proteins

Keratolytic agents reduce corneocyte adhesion by dissolving the intercellular matrix or disrupting hydrogen bonds in keratin filaments; Retinoids modulate the transcription of keratin genes to normalize keratinocyte differentiation and proliferation.