Filaggryns

Filaggryns are a family of specialized proteins that play a crucial role in skin barrier formation and function. They belong to the S100 family of calcium-binding proteins and are primarily expressed in the outermost layer of the epidermis, known as the stratum corneum. Filaggryns are essential for the aggregation of keratin filaments within keratinocytes, facilitating the development of the skin’s structural integrity and resilience.

The gene encoding filaggryns is called FLG, and mutations in this gene are strongly associated with skin conditions such as atopic dermatitis and ichthyosis vulgaris. Such mutations can impair the formation of an effective skin barrier, leading to increased transepidermal water loss and vulnerability to environmental irritants and allergens.

During epidermal differentiation, profilaggrin, a large precursor protein, is processed into mature filaggryns. This processing involves the proteolytic cleavage of profilaggrin within keratinocytes as they move toward the skin surface. Filaggryns then bind to keratin intermediate filaments, promoting their aggregation into dense, protective bundles that give the skin its mechanical strength.

Beyond structural support, filaggryns also contribute to the skin’s hydration by releasing amino acids upon degradation, which help maintain skin moisture. Additionally, they are involved in the formation of the skin’s natural moisturizing factors (NMF).

Research into filaggryns continues to provide insights into skin biology and the pathogenesis of skin disorders. Their importance in skin health underscores their potential as targets for therapeutic intervention in barrier-related skin diseases.