title: Annexin 1 regulation in human epidermal cells.
abstract: Annexin 1 (named p35, lipocortin I or calpactin II), initially described as a glucocorticoid induced protein, belongs to a new characterized family of intracellular proteins. In the skin, the role of annexins has still not been elucidated. In a previous study, we reported the localization of annexin 1 in both freshly isolated human epidermal cells and in cultured keratinocytes using immunofluorescence, FACS analysis and immunoblotting techniques. The protein was characterized by Western blot and immunoprecipitation as a 35 kDa protein. Results from in vivo studies confirmed the presence of annexin 1 in basal and suprabasal layers of normal human skin with modified reactivity patterns in hyperproliferative lesions. In the present study, the role of glucocorticoids in annexin 1 regulation was investigated in epidermal cells by Western blot and immunoprecipation assays. In contrast to other studies, we found that glucocorticoid treatment of epidermal cells led to a decrease in annexin 1 content in the cytoplasm and the membranes of cells. As annexin 1 was not detected in the nucleus of cells, we conclude that there was a down regulation of annexin 1 after glucocorticoid treatments rather than a translocation of the protein to the nucleus. Despite the absence of the signal peptide sequence necessary for protein secretion, annexin 1 was released in the keratinocyte culture medium. We found that the protein was secreted only in low Ca2+ medium (0.15 mM), this process required an active metabolism.
authors.affiliation: INSERM Unité 346, Clin. Dermatologique Hôpital E. Herriot, Lyon, France.
authors.forename: M
authors.initials: M
authors.lastname: Serres
authors.forename: C
authors.initials: C
authors.lastname: Comera
authors.forename: D
authors.initials: D
authors.lastname: Schmitt
mesh_terms: D017305:Annexin A1 / Q000378:metabolism*; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D015536:Down-Regulation; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology; D015603:Keratinocytes / Q000187:drug effects / Q000378:metabolism; D015735:Mifepristone / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology; D012867:Skin / Q000187:drug effects / Q000378:metabolism*; D014221:Triamcinolone / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D017305:Annexin A1; D014221:Triamcinolone; D015735:Mifepristone; C012716:amcinonide; D011374:Progesterone; D003907:Dexamethasone; D006854:Hydrocortisone