Abstract
Apoptosis is initiated when Bcl-2 and its prosurvival relatives are engaged by proapoptotic BH3-only proteins via interaction of its BH3 domain with a groove on the Bcl-2-like proteins. These interactions have been considered promiscuous, but our analysis of the affinity of eight BH3 peptides for five Bcl-2-like proteins has revealed that the interactions vary over 10,000-fold in affinity, and accordingly, only certain protein pairs associate inside cells. Bim and Puma potently engaged all the prosurvival proteins comparably. Bad, however, bound tightly to Bcl-2, Bcl-xL, and Bcl-w but only weakly to A1 and not to Mcl-1. Strikingly, Noxa bound only Mcl-1 and A1. In accord with their complementary binding, Bad and Noxa cooperated to induce potent killing. The results suggest that apoptosis relies on selective interactions between particular subsets of these proteins and that it should be feasible to discover BH3-mimetic drugs that inactivate specific prosurvival targets.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Apoptosis / physiology*
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Apoptosis Regulatory Proteins
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Bcl-2-Like Protein 11
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Binding, Competitive
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Biosensing Techniques
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Carrier Proteins / chemistry
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Carrier Proteins / genetics
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Carrier Proteins / metabolism
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Cell Survival / physiology*
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Genetic Complementation Test
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Humans
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In Vitro Techniques
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Ligands
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Membrane Proteins / chemistry
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Mice
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Models, Biological
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Models, Molecular
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Molecular Sequence Data
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Myeloid Cell Leukemia Sequence 1 Protein
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Neoplasm Proteins / chemistry
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Neoplasm Proteins / genetics
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Neoplasm Proteins / metabolism
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Peptide Fragments / chemistry
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Peptide Fragments / genetics
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Peptide Fragments / metabolism*
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Protein Structure, Tertiary
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Proteins / chemistry
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Proteins / genetics
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Proteins / metabolism
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Proto-Oncogene Proteins / chemistry
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism*
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Proto-Oncogene Proteins c-bcl-2 / chemistry
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Proto-Oncogene Proteins c-bcl-2 / genetics
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Proto-Oncogene Proteins c-bcl-2 / metabolism*
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Sequence Homology, Amino Acid
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bcl-X Protein
Substances
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Apoptosis Regulatory Proteins
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BCL2L1 protein, human
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BCL2L11 protein, human
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BCL2L2 protein, human
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Bax protein (53-86)
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Bcl-2-Like Protein 11
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Bcl2l1 protein, mouse
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Bcl2l11 protein, mouse
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Carrier Proteins
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Ligands
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Mcl1 protein, mouse
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Membrane Proteins
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Myeloid Cell Leukemia Sequence 1 Protein
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Neoplasm Proteins
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Peptide Fragments
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Proteins
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-bcl-2
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Recombinant Proteins
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bcl-X Protein