molecular identification and expression analysis of filaggrin-2, a member of the s100 fused-type protein family分子识别和表达分析filaggrin-2 s100的成员fused-type蛋白质家族.pdfVIP

Molecular Identification and Expression Analysis of Filaggrin-2, a Member of the S100 Fused-Type Protein Family ¨ ¨ Zhihong Wu, Britta Hansmann, Ulf Meyer-Hoffert, Regine Glaser, Jens-Michael Schroder* Department of Dermatology, University Hospital of Schleswig-Holstein, Kiel, Germany Abstract Genes of the S100 fused-type protein (SFTP) family are clustered within the epidermal differentiation complex and encode essential components that maintain epithelial homeostasis and barrier functions. Recent genetic studies have shown that mutations within the gene encoding the SFTP filaggrin cause ichthyosis vulgaris and are major predisposing factors for atopic dermatitis. As a vital component of healthy skin, filaggrin is also a precursor of natural moisturizing factors. Here we present the discovery of a member of this family, designated as filaggrin-2 (FLG2) that is expressed in human skin. The FLG2 gene encodes a histidine- and glutamine-rich protein of approximately 248 kDa, which shares common structural features with other SFTP members, in particular filaggrin. We found that FLG2 transcripts are present in skin, thymus, tonsils, stomach, testis and placenta. In cultured primary keratinocytes, FLG2 mRNA expression displayed almost the same kinetics as that of filaggrin following Ca2+ stimulation, suggesting an important role in molecular regulation of epidermal terminal differentiation. We provide evidences that like filaggrin, FLG2 is initially expressed by upper granular cells, proteolytically processed and deposited in the stratum granulosum and stratum corneum (SC) layers of normal epidermis. Thus, FLG2 and filaggrin may have overlapping and perhaps synergistic roles in the formation of the epidermal barrier, protectin