Skin Calcium Binding Protein is Localized in the Cytoplasm of the Basal Layer of the Epidermis

Abstract

Using a serum raised in rabbits against a calcium binding protein extracted from rat skin, the cutaneous localization of this protein was studied by indirect immunofluorescence. The skin calcium binding immunoreactivity was found in the epidermis but not in the dermis; it was localized in the cytoplasm of the basal cell layer of both skin and malpighian mucosa. There was not species specificity; this allowed the tracing of the protein in human epidermis as well where it was also expressed only in the basal cells. This is the first demonstration of the unique localization of a specific protein within the cytoplasm of the basal cell layer of the epidermis. This localization may help to elucidate the physiological role of this protein.

Skin calcium-binding protein immunoreactivity in basal cell carcinoma

“…Neither the FITC labelled sheep anti-rabbit IgG antiserum nor the FITC labelled goat ami-human IgG antiserum reacted with normal skin or tumorous material. Previous absorption of SCaBP antiserum with purified SCaBP abolished the staining as detailed previously (Saurat et al, 1981a). No staining was observed with pre-immune serum.…”

“…A rabbit serum containing antibodies against purified rat SCaBP was obtained as previously described (Laouri et al., 1980;Saurat et al, 1981a). Briefly, SCaBP from whole Sprangley albino rat skin was extracted by homogenization, and purified by chromatography.…”

Calcifying Basal Cell Carcinomas

“…3 Skin calciumbinding protein immunoreactivity has also been localized to the cytoplasm of basal epidermal cells in humans. 4 In the study of Merot et al, 5 skin calcium-binding protein immunoreactivity was demonstrated in all human basal cell carcinoma cells regardless of histologic type or position of cells in relation to the basement membrane. The only squamous cell carcinoma examined showed skin calcium-binding protein immunoreactivity in only a few cells confined to the periphery of the tumor.…”

Expression of Cytoplasmic Antigens Linked to Orthokeratosis During the Development of Parakeratosis in Newborn Mouse Tail Epidermis

“…c) Serum to skin calcium-binding protein (SCaBP): this serum was raised in rabbit to a skin protein (mol.wt. 12,000) with calcium-binding activity [q which is expressed in the cytoplasm of epidermal basal cells [14]; the serum reacted identically with basal cells of orthokeratotic, parakeratotic, and mucous epithelia. The titre was 1 :640, the working dilution 1 /20.…”