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Sustained release of Smac/DIABLO from mitochondria commits to undergo UVB-induced apoptosis.
- Source :
-
Apoptosis : an international journal on programmed cell death [Apoptosis] 2003 Jun; Vol. 8 (3), pp. 291-9. - Publication Year :
- 2003
-
Abstract
- Apoptotic response of keratinocytes to UVB irradiation has physiological significance on photocarcinogenesis. Here, we show that the sustained release of Smac/DIABLO from mitochondria is an important event for the onset of apoptosis in keratinocytes exposed to UVB irradiation. In human keratinocyte HaCaT cells, UVB irradiation at 500 J/m(2), but not at 150 J/m(2), induces apoptosis. Significant activations of caspases-9 and -3, and slight activation of caspase-7 were observed only in 500 J/m(2) UVB irradiated HaCaT cells. Correspondingly, the cleavage of PARP, a substrate of caspases-3 and -7, was detected in cells irradiated at 500 J/m(2) UVB, but not at 150 J/m(2). However, with both 150 and 500 J/m(2) UVB irradiation, cytochrome c, an activator of caspase-9 via the formation of apoptosome, was released from mitochondria to the cytosol at the same extent. In contrast, significant amounts of Smac/DIABLO are released from mitochondria to the cytosol only with 500 J/m(2) UVB irradiation, and that the level of XIAP is decreased. These results suggest that the extent of Smac/DIABLO efflux from mitochondria is a determinant whether a cell will undergo apoptosis or survival.
- Subjects :
- Apoptosis physiology
Apoptosis Regulatory Proteins
Caspases metabolism
Caspases radiation effects
Cell Line, Transformed
Cytochromes c metabolism
Cytochromes c radiation effects
Cytosol metabolism
Cytosol radiation effects
Fluorescent Antibody Technique
Humans
Intracellular Signaling Peptides and Proteins
Keratinocytes metabolism
Mitochondria metabolism
Protein Transport physiology
Protein Transport radiation effects
Proteins metabolism
Proteins radiation effects
X-Linked Inhibitor of Apoptosis Protein
Apoptosis radiation effects
Carrier Proteins metabolism
Carrier Proteins radiation effects
Keratinocytes radiation effects
Mitochondria radiation effects
Mitochondrial Proteins metabolism
Mitochondrial Proteins radiation effects
Ultraviolet Rays
Subjects
Details
- Language :
- English
- ISSN :
- 1360-8185
- Volume :
- 8
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Apoptosis : an international journal on programmed cell death
- Publication Type :
- Academic Journal
- Accession number :
- 12766489
- Full Text :
- https://doi.org/10.1023/a:1023629023696