Fos and jun proteins are specifically expressed during differentiation of human keratinocytes.
Activator protein 1 (AP-1) proteins play key roles in the regulation of cell proliferation and differentiation. In this study we investigated the expression of Fos and Jun proteins in different models of terminal differentiation of human keratinocytes and in skin from psoriasis patients. All Jun and Fos proteins, with the exception of FosB, were efficiently expressed in keratinocytes in monolayer cultures. In contrast, in normal epidermis as well as in organotypic epidermal cultures, the expression pattern of AP-1 proteins was dependent on the differentiation stage. Fos proteins were readily detected in nuclei of keratinocytes of basal and suprabasal layers. JunB and JunD were expressed in all layers of normal epidermis. Interestingly, expression of c-Jun started suprabasally, then disappeared and became detectable again in distinct cells of the outermost granular layer directly at the transition zone to the stratum corneum. In psoriatic epidermis, c-Jun expression was prominent in both hyperproliferating basal and suprabasal keratinocytes, whereas c-Fos expression was unchanged. These data indicate that AP-1 proteins are expressed in a highly specific manner during terminal differentiation of keratinocytes and that the enhanced expression of c-Jun in basal and suprabasal keratinocytes might contribute to the pathogenesis of psoriasis.
Mehic
Denis
D
Department of Dermatology, University of Vienna Medical School, Vienna, Austria.
Bakiri
Latifa
L
Ghannadan
Minoo
M
Wagner
Erwin F
EF
Tschachler
Erwin
E
D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000166:cytology* / Q000378:metabolism*; D009924:Organ Culture Techniques; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D011565:Psoriasis / Q000378:metabolism* / Q000473:pathology; D018808:Transcription Factor AP-1 / Q000378:metabolism
D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D018808:Transcription Factor AP-1