Apaf-1 Oligomerizes into Biologically Active ∼700-kDa and Inactive ∼1.4-MDa Apoptosome Complexes*

By K. Cain, S. Bratton, C. Langlais, G. Walker, David G. Brown, Xiao-Ming Sun, G. Cohen. Journal of Biological Chemistry, 2000

247 citations recorded by the source corpus.

Apaf-1, by binding to and activating caspase-9, plays a critical role in apoptosis. Oligomerization of Apaf-1, in the presence of dATP and cytochrome c, is required for the activation of caspase-9 and produces a caspase activating apoptosome complex. Reconstitution studies with recombinant proteins have indicated that the size of this complex is very large in the order of ∼1.4 MDa. We now demonstrate that dATP activation of cell lysates results in the formation of two large Apaf-1-containing apoptosome complexes with M r values of ∼1.4 MDa and ∼700 kDa. Kinetic analysis demonstrates that in vitro the ∼700-kDa complex is produced more rapidly than the ∼1.4 MDa complex and exhibits a much greater ability to activate effector caspases. Significantly, in human tumor monocytic cells undergoing apoptosis after treatment with either etoposide orN-tosyl-l-phenylalanyl chloromethyl ketone (TPCK), the ∼700-kDa Apaf-1 containing apoptosome complex was predominately formed. This complex processed effector caspases. Thus, the ∼700-kDa complex appears to be the correctly formed and biologically active apoptosome complex, which is assembled during apoptosis.

Subfields: Molecular Biology

View Paper: https://www.semanticscholar.org/paper/960307a27bf54dcfd4739c8dd45c59c558a68c3e

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Citations in the corpus

Extrinsic versus intrinsic apoptosis pathways in anticancer chemotherapy (2006, background): “The release of cytochrome c from mitochondria directly triggers caspase-3 activation through formation of the cytochrome c/Apaf-1/caspase-9-containing apoptosome complex (Cain et al., 2000).”
Heat-shock protein 70 inhibits apoptosis by preventing recruitment of procaspase-9 to the Apaf-1 apoptosome (2000, background): “The resulting ‘apoptosome’ recruits and activates procaspase-9, which in turn recruits, cleaves and activates caspase-3 and caspase-7”
The Ripoptosome, a signaling platform that assembles in response to genotoxic stress and loss of IAPs. (2011, methodology): “Cellular lysates were separated on a Superose 6 HR 10/30 size-exclusion column and an AKTA Purifier protein purification system (GE Healthcare), essentially as described previously (Cain et al., 2000).”
Apoptotic pathways: paper wraps stone blunts scissors. (2000, background): “This induces Apaf-1 oligomerization, and in response to environmental and developmental sig- the Apaf-1 “apoptosome” recruits and activates procasnals, a complex decision-making system with the mito- pase-9 (Cain et al., 2000).”