EPPK1

EPPK1 is a human gene that encodes epiplakin, a large cytoskeletal protein belonging to the plakin family. Epiplakin is expressed in epithelial tissues, including the skin, and functions as a cytoskeletal crosslinker that helps organize and stabilize the keratin intermediate filament network. By linking keratin filaments to each other and to cell junctional complexes, epiplakin contributes to the mechanical resilience of epithelial cells under stress.

The protein is characterized by extensive spectrin-like repeat domains and, unlike some plakins, does not contain the canonical actin-binding domain found in other family members. Epiplakin localizes mainly in the cytoplasm and is enriched near keratin networks and cell–cell junctions, where it collaborates with keratins and possibly other junctional components to maintain cytoskeletal organization.

Expression of EPPK1 is broad across stratified epithelia, including the skin, oral mucosa, esophagus, and cornea. Its function appears to be particularly relevant during conditions of mechanical or oxidative stress, where stabilization of the keratin network supports cell integrity. Regulation of epiplakin may involve cellular signaling and post-translational modifications, and alternative splicing can yield multiple isoforms that may differ in localization or function.

In the clinical and research context, direct causal disease associations with EPPK1 mutations are not yet well defined. However, altered epiplakin expression has been observed in some skin disorders and cancer studies, and animal models indicate that loss of epiplakin can disrupt keratin organization and epithelial integrity, supporting its role in tissue mechanics and wound response.