Hornerin (HRNR)

Hornerin (HRNR) is a large, repetitive member of the S100 fused-type protein family. It is classified as a structural protein crucial in the processes of epidermal differentiation, cornification, and skin barrier formation. Hornerin is predominately expressed in keratinocytes and localizes to the periphery of keratohyalin granules in the upper granular layer of the epidermis, becoming a constituent of the cornified envelope after processing by proteolytic enzymes and cross-linking. Its expression is upregulated during wound healing, in psoriatic skin, and dynamically regulated during keratinocyte differentiation, but decreased in chronic inflammatory conditions such as atopic dermatitis. HRNR fragments display antimicrobial functions, and the parent protein undergoes post-translational modifications such as deimination. In cancer, especially breast cancer and pancreatic ductal adenocarcinoma, hornerin is implicated in regulating tumor angiogenesis, apoptosis, and cellular proliferation, with varying expression in subtypes and disease contexts. No therapeutically relevant drugs or pharmacological targeting are documented, as hornerin is not considered a canonical therapeutic receptor or enzyme target. Some alternative aliases listed in public databases (notably S100A16 and S100a18) appear to be misattributed or infrequent; the standard conventions reserve S100A16 for a different gene/protein.

Other names

S100 fused-type protein hornerinS100A18Filaggrin family member 3FLG3Intermediate filament-associated proteinHRNRHornerinS100A16

Not applicable/none directly known (not a classic drug target)