Expression of annexin I in freshly isolated human epidermal cells and in cultured keratinocytes.
Annexin I belongs to a newly characterized family of intracellular proteins involved in the regulation of the production of inflammatory lipid mediators such as prostaglandins and leucotrienes. Annexin I (named p35, lipocortin I or calpactin II) was initially described as a protein inducible by glucocorticoids. In the skin, the role of annexins has still not been elucidated. In the study reported here we investigated the expression of annexin I both in freshly isolated epidermal cells and in cultured keratinocytes using immunofluorescence, FACS analysis and immunoblotting techniques. Using epidermal cells freshly isolated from normal skin, annexin I was detected by double immunostaining mainly in basal and suprabasal keratinocytes. Langerhans cells isolated from Ficoll gradient were faintly stained compared with keratinocytes. Annexin I was also highly expressed in keratinocytes maintained in culture in a serum-free medium without hydrocortisone. By confocal microscopy, annexin I was shown to be mainly localized in the cytoplasm of the cells. The protein was characterized by Western blot and immunoprecipitation as a 35-kDa protein in freshly isolated epidermal cells and cultured keratinocytes. Results from in vivo studies confirmed the presence of annexin I in the basal and suprabasal layers of normal human skin with modified reactivity patterns in hyperproliferative lesions.
Serres
M
M
INSERM Unité 346, Clin. Dermatologique Hôpital E. Herriot, Lyon, France.
Viac
J
J
Comera
C
C
Schmitt
D
D
D017305:Annexin A1 / Q000096:biosynthesis*; D015153:Blotting, Western; D002478:Cells, Cultured; D004817:Epidermis / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006801:Humans; D007124:Immunoenzyme Techniques; D015603:Keratinocytes / Q000378:metabolism*
D017305:Annexin A1