Characterization of Mouse Profilaggrin: Evidence for Nuclear Engulfment and Translocation of the Profilaggrin B-Domain During Epidermal Differentiation

The study characterized the mouse profilaggrin gene, focusing on the B-domain's role during epidermal differentiation. Researchers found that the B-domain, but not filaggrin, localized to the nuclei of upper granular and transition layer cells, suggesting a nuclear targeting sequence. Immunofluorescence and immunoelectron microscopy confirmed that keratohyalin granules containing the B-domain were engulfed by the nucleus, indicating an active process of nuclear translocation. This process might signal the final nuclear events of terminal differentiation, contributing to the understanding of molecular mechanisms in epidermal differentiation.