The Mixed Lineage Kinase Leucine-Zipper Protein Kinase Exhibits a Differentiation-Associated Localization in Normal Human Skin and Induces Keratinocyte Differentiation Upon Overexpression

The study explored the role of leucine-zipper protein kinase (ZPK) in human skin, revealing its specific localization in the granular layer of the epidermis and the inner root sheath of hair follicles. Overexpression of ZPK in keratinocytes resulted in growth arrest and increased filaggrin expression, indicating its involvement in terminal differentiation. These findings suggested that ZPK played a crucial role in keratinocyte differentiation and could impact epidermal homeostasis, with potential implications for understanding skin biology and disorders. The study also speculated on ZPK's role in apoptosis, nuclear degradation, and lipid organization.