The First α Helix of Bax Plays a Necessary Role in Its Ligand-Induced Activation by the BH3-Only Proteins Bid and PUMA
The mechanism by which some BH3-only proteins of the Bcl-2 family directly activate the “multidomain” proapoptotic member Bax is poorly characterized. We report that the first α helix (Hα1) of Bax specifically interacts with the BH3 domains of Bid and PUMA but not with that of Bad. Inhibition of thi...
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Veröffentlicht in: | Molecular cell 2004-12, Vol.16 (5), p.807-818 |
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Sprache: | eng |
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Zusammenfassung: | The mechanism by which some BH3-only proteins of the Bcl-2 family directly activate the “multidomain” proapoptotic member Bax is poorly characterized. We report that the first α helix (Hα1) of Bax specifically interacts with the BH3 domains of Bid and PUMA but not with that of Bad. Inhibition of this interaction, by a peptide comprising Hα1 or by a mutation in this helix, prevents ligand-induced activation of Bax by Bid, PUMA, or their BH3 peptides. Hα1-mutated Bax, which can mediate death induced by Bad or its BH3 peptide, does not mediate that induced by Bid, PUMA, or their BH3 peptides. The response of Hα1-mutated Bax to Bid can be restored by a compensating mutation in Bid BH3. Thus, a specific interaction between Bax Hα1 and their BH3 domains allows Bid and PUMA to function as “death agonists” of Bax, whereas Bad recruits Bax activity through a distinct pathway. |
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ISSN: | 1097-2765 1097-4164 |
DOI: | 10.1016/j.molcel.2004.10.028 |