Formation of apoptosome is initiated by cytochrome c-induced dATP hydrolysis and subsequent nucleotide exchange on Apaf-1
- Howard Hughes Medical Institute and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
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Contributed by Xiaodong Wang, September 13, 2005
Abstract
Apoptosis in metazoans is executed by a group of intracellular proteases named caspases. One of the caspase-activating pathways in mammals is initiated by the release of cytochrome c from mitochondria to cytosol, where it binds to Apaf-1 to form a procaspase-9-activating heptameric protein complex named apoptosome. We report here the reconstitution of this pathway with purified recombinant Apaf-1, procaspase-9, procaspase-3, and cytochrome c from horse heart. Apaf-1 contains a dATP as a cofactor. Cytochrome c binding to Apaf-1 induces hydrolysis of dATP to dADP, which is subsequently replaced by exogenous dATP. The dATP hydrolysis and exchange on Apaf-1 are two required steps for apoptosome formation.
Footnotes
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↵ * To whom correspondence should be addressed. E-mail: xwang{at}biochem.swmed.edu.
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Author contributions: H.-E.K., F.D., M.F., and X.W. designed research; H.-E.K., F.D., and M.F. performed research; F.D. contributed new reagents/analytic tools; H.-E.K., M.F., and X.W. analyzed data; and H.-E.K. and X.W. wrote the paper.
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This contribution is part of the special series of Inaugural Articles by members of the National Academy of Sciences elected on April 20, 2004.
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Conflict of interest statement: No conflicts declared.
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Freely available online through the PNAS open access option.
- Copyright © 2005, The National Academy of Sciences
