The 1.4-MDa apoptosome is a critical intermediate in apoptosome maturation
1 Division of Nephrology, Hypertension and Transplantation, Department of Medicine; and 2 College of Dentistry, University of Florida, Gainesville, Florida 32610 Submitted 3 June 2003 ; accepted in final form 27 April 2004 Previously, we demonstrated that both 150 mM KCl and alkaline pH inhibit cyto...
Gespeichert in:
Veröffentlicht in: | American Journal of Physiology: Cell Physiology 2004-09, Vol.287 (3), p.C664-C672 |
---|---|
Hauptverfasser: | , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | 1 Division of Nephrology, Hypertension and Transplantation, Department of Medicine; and 2 College of Dentistry, University of Florida, Gainesville, Florida 32610
Submitted 3 June 2003
; accepted in final form 27 April 2004
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 700-kDa apoptosome matures through a 1.4-MDa intermediate before a 700-kDa apoptosome is reformed and procaspase-3 is activated. We further demonstrate that 150 mM KCl interferes with the conversion of the initial 700-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.
caspase; pH; potassium; apoptosis
Address for reprint requests and other correspondence: M. S. Segal, PO Box 100224, Gainesville, FL 32610 (E-mail: segalms{at}medicine.ufl.edu ). |
---|---|
ISSN: | 0363-6143 1522-1563 |
DOI: | 10.1152/ajpcell.00232.2003 |