title: Interaction of the profilaggrin N-terminal domain with loricrin in human cultured keratinocytes and epidermis.
abstract: The relationship between the two coexpressed differentiation markers, profilaggrin and loricrin, is not clear right now. In this study, we explored the interaction of profilaggrin N-terminal domain (PND) with loricrin in keratinocytes and epidermis. Confocal immunofluorescence microscopic analysis of human epidermis showed that PND colocalized with loricrin. Loricrin nucleofected into HaCaT cells colocalized with PND in the nucleus and cytoplasm. The PND localizes to both the nucleus and cytoplasm of epidermal granular layer cells. Nucleofected PND also colocalized with keratin 10 (K10) in the nucleus and cytoplasm. Immunoelectron microscopic analysis of human epidermis confirmed the findings in nucleofected keratinocytes. Yeast two-hybrid assays showed that the B domain of human and mouse PND interacted with loricrin. The glutathione S-transferase (GST) pull-down analysis using recombinant GST-PND revealed that PND interacted with loricrin and K10. Knockdown of PND in an organotypic skin culture model caused loss of filaggrin expression and a reduction in both the size and number of keratohyalin granules, as well as markedly reduced expression of loricrin. Considering that expression of PND is closely linked to keratinocyte terminal differentiation, we conclude that PND interacts with loricrin and K10 in vivo and that these interactions are likely to be relevant for cornified envelope assembly and subsequent epidermal barrier formation.
authors.affiliation: Department of Dermatology, Faculty of Medicine, Kagawa University, Kagawa, Japan. kyoneda@med.kagawa-u.ac.jp
authors.forename: Kozo
authors.initials: K
authors.lastname: Yoneda
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Owen T
authors.initials: OT
authors.lastname: Lawrence
authors.forename: Jessica
authors.initials: J
authors.lastname: Huard
authors.forename: Toshio
authors.initials: T
authors.lastname: Demitsu
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kubota
authors.forename: Richard B
authors.initials: RB
authors.lastname: Presland
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism*; D000091344:Filaggrin Proteins; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism*; D053550:Keratin-10 / Q000378:metabolism; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D054730:Protein Interaction Domains and Motifs / Q000235:genetics / Q000502:physiology*; D034741:RNA, Small Interfering / Q000494:pharmacology
chemical_list: C000717249:FLG protein, human; D000091344:Filaggrin Proteins; D007381:Intermediate Filament Proteins; D008565:Membrane Proteins; D034741:RNA, Small Interfering; C064554:loricrin; D053550:Keratin-10