The 1.4-MDa apoptosome is a critical intermediate in apoptosome maturation

被引:15
作者
Beem, E
Holliday, LS
Segal, MS
机构
[1] Univ Florida, Dept Med, Div Nephrol Hypertens & Transplantat, Gainesville, FL 32610 USA
[2] Univ Florida, Coll Dent, Gainesville, FL 32610 USA
来源
AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY | 2004年 / 287卷 / 03期
关键词
caspase; pH; potassium; apoptosis;
D O I
10.1152/ajpcell.00232.2003
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
Previously, we demonstrated that both 150 mM KCl and alkaline pH inhibit cytochrome c-mediated activation of procaspase-3 in a unique manner. To determine the mechanism of inhibition, we analyzed the effect of KCl and alkaline pH on the formation of apoptosomes (a large complex consisting of cytochrome c, Apaf-1, and procaspase-9/caspase-9) in vitro. Our results suggest that an initial similar to700-kDa apoptosome matures through a 1.4-MDa intermediate before a similar to700-kDa apoptosome is reformed and procaspase-3 is activated. We further demonstrate that 150 mM KCl interferes with the conversion of the initial similar to700-kDa apoptosome to the 1.4-MDa intermediate, while alkaline pH "traps" the apoptosome in the 1.4-MDa intermediate. Analysis of the cleaved state of procaspase-9 and procaspase-3 suggests that the 1.4-MDa intermediate may be required for cleavage of procaspase-9. Consistent with these results, in vivo data suggest that blocking acidification during the induction of apoptosis inhibits activation of procaspase-3. On the basis of these results, we propose a model of apoptosome maturation.
引用
收藏
页码:C664 / C672
页数:9
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