Keratin and structural proteins in the stratum corneum (SC proteins)

The stratum corneum (SC) represents the final stage of epidermal differentiation, functioning as a critical biosensor and physical barrier against environmental insults. It consists of corneocytes filled with a dense network of keratin intermediate filaments (primarily K1 and K10) and surrounded by a cornified envelope (CE) composed of cross-linked proteins like loricrin, involucrin, and filaggrin (Source: PubMed, PMID: 22408357). These structural proteins provide mechanical strength and facilitate water retention through the production of Natural Moisturizing Factors (NMF) derived from filaggrin degradation. Dysregulation of these proteins is central to the pathogenesis of diseases such as atopic dermatitis, where filaggrin mutations lead to barrier failure, and psoriasis, characterized by abnormal keratin expression and hyperkeratosis. Therapeutic strategies targeting these proteins include the use of keratolytics to promote desquamation by breaking down protein aggregates and retinoids to influence the differentiation program of keratinocytes (Source: StatPearls, 'Physiology, Stratum Corneum'). By modulating the synthesis and degradation of these structural components, drugs can restore the SC's integrity and alleviate symptoms of various dermatological conditions.

Other names

Stratum corneum proteinsCorneocyte structural proteinsEpidermal keratinsCornified envelope proteinsKeratin filaments

Keratolytic agents (e.g., salicylic acid, urea) reduce corneocyte adhesion by solubilizing intercellular lipids and disrupting desmosomal attachments, while retinoids and vitamin D analogs modulate the gene expression of keratins and cornified envelope precursors to normalize the differentiation and desquamation process (Source: StatPearls, PMID: 30725737; PubMed, PMID: 25607907).