Keratin (KRT) (KRT)

Keratins are a large family of intermediate filament proteins essential for the structural integrity and mechanical resilience of epithelial cells and their derivatives, such as hair and nails (Source: UniProt, Keratin family, 2024). They are classified into Type I (acidic) and Type II (basic-to-neutral) proteins, which heteropolymerize to form the dense cytoskeletal framework required for protecting tissues against environmental and mechanical stress (Source: Moll et al., The Keratin Polypeptides, 2008). Beyond their structural role, keratins participate in intracellular signaling, cell transport, and the regulation of protein synthesis and cell growth (Source: Bragulla & Homberger, Structure and functions of keratin, 2009). In clinical practice, keratins are significant targets for dermatological treatments; keratolytic agents like salicylic acid and urea are used to treat hyperkeratotic conditions by promoting the softening and shedding of the stratum corneum (Source: StatPearls, Keratolytics, 2023). Furthermore, retinoids are employed to modulate keratin gene expression in diseases like acne and psoriasis, while specific keratin fragments serve as valuable serum biomarkers for monitoring various epithelial-derived cancers.

Other names

CytokeratinIntermediate filament proteinHard keratinSoft keratinEpithelial keratinKRT family

Keratolytic agents work by increasing the hydration of the stratum corneum and dissolving the intercellular cement that binds keratinocytes, or by directly denaturing keratin proteins, leading to the softening and shedding of the outer skin layer (Source: StatPearls, Keratolytics, 2023). Retinoids modulate the expression of keratin genes by binding to nuclear retinoic acid receptors (RAR) and retinoid X receptors (RXR), thereby normalizing keratinocyte differentiation and proliferation (Source: NIH, Retinoids in Dermatology, 2022).