1α,25-Dihydroxyvitamin D3 [1α,25(OH)2D3] regulates cellular growth and differentiation. We show that in keratinocytes, 1α,25(OH)2D3 reduces concentrations of the messenger RNA of IEX-1, the product of which blocks Fas- or tumor necrosis factor type α-induced apoptosis in various cells. In sub-confluent keratinocyte cultures, the addition of 1α,25(OH)2D3 in amounts that induce growth arrest, reduces IEX-1 mRNA concentrations. In confluent cells, 1α,25(OH)2D3 initially reduces and then increases IEX-1 mRNA concentrations. IEX-1 protein is localized in the nucleus and perinuclear region of keratinocytes. In sub-confluent cells, 1α,25(OH)2D3 translocates IEX-1 protein from the nucleus to the perinuclear region and cytoplasm. Since IEX-1 has recently been shown to regulate cell survival and number, we suggest that IEX-1 may play a role in keratinocyte growth and differentiation and that 1α,25(OH)2D3 may reduce keratinocyte growth via a reduction in IEX-1 mRNA and a change in the intracellular distribution of IEX-1 protein.
|Original language||English (US)|
|Number of pages||6|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Oct 29 1998|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology