Formation of apoptosome is initiated by cytochrome c-induced dATP hydrolysis and subsequent nucleotide exchange on Apaf-1.
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.
Kim
Hyun-Eui
HE
Howard Hughes Medical Institute and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
Du
Fenghe
F
Fang
Min
M
Wang
Xiaodong
X
D000818:Animals; D017209:Apoptosis; D053477:Apoptotic Protease-Activating Factor 1; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism*; D003838:Deoxyadenine Nucleotides / Q000378:metabolism*; D004789:Enzyme Activation; D006736:Horses; D006868:Hydrolysis; D007425:Intracellular Membranes / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D015388:Organelles / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism*
D053477:Apoptotic Protease-Activating Factor 1; D003838:Deoxyadenine Nucleotides; D047908:Intracellular Signaling Peptides and Proteins; D011506:Proteins; D045304:Cytochromes c; D053148:Caspase 3; D020169:Caspases; C026600:2'-deoxyadenosine triphosphate