Recombinant Human FLG protein

**Background of FLG Recombinant Protein**

Filaggrin (FLG) is a crucial epidermal protein encoded by the *FLG* gene, primarily expressed in the stratum granulosum of the epidermis. It plays a pivotal role in skin barrier formation by aggregating keratin intermediate filaments, facilitating the compaction of corneocytes during terminal differentiation. Post-translationally processed from its precursor, profilaggrin, filaggrin is further degraded into free amino acids and derivatives (e.g., urocanic acid), which contribute to skin hydration, pH regulation, and UV protection. Mutations in the *FLG* gene are strongly associated with impaired barrier function, leading to dermatological disorders such as atopic dermatitis, ichthyosis vulgaris, and increased susceptibility to allergic sensitization.

The development of recombinant filaggrin (rFLG) emerged to address challenges in studying filaggrin's molecular mechanisms and therapeutic potential. Native filaggrin is notoriously difficult to isolate due to its insolubility and rapid degradation in vivo. Recombinant expression systems (e.g., bacterial, yeast, or mammalian cell lines) enable scalable production of stable, purified FLG variants for experimental and clinical applications. rFLG has been instrumental in elucidating filaggrin's role in epidermal homeostasis, modeling disease pathologies, and screening barrier-restoring compounds.

Current research leverages rFLG to develop topical formulations or biologics aimed at compensating for filaggrin deficiency in genetic skin disorders. However, challenges persist, including maintaining protein stability, ensuring proper post-translational modifications, and mimicking native protein interactions. Advances in protein engineering and delivery systems continue to refine rFLG’s utility, positioning it as a promising tool for both mechanistic studies and translational dermatology.