A stapled BID BH3 helix directly binds and activates BAX
A stapled BID BH3 helix directly binds and activates BAX
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DOI：
10.1016/j.molcel.2006.08.020
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发表时间：
2006-10-20
期刊：
影响因子：
16
通讯作者：
Korsmeyer, Stanley J.
中科院分区：
文献类型：
--
作者：
Walensky, Loren D.;Pitter, Kenneth;Korsmeyer, Stanley J.
BAX是一种多结构域促凋亡BCL-2家族蛋白，其存在于胞质溶胶中，直到被不完全理解的触发机制激活，这促进BAX易位至线粒体和下游死亡事件。BAX是否通过直接接触BCL-2家族中仅选择BH 3的成员而被激活，这是一个高度争议的问题。在这里，我们检测和定量BAX和烃钉合BID BH 3结构域之间的直接结合相互作用，其在体外以纳摩尔剂量触发BAX的功能激活。需要化学强化BID BH 3 α螺旋性以揭示直接BID BH 3-BAX缔合。我们通过表征与抗凋亡BCL-X-L相互作用但不结合或激活BAX的钉合BAD BH 3肽来证实这种BH 3相互作用的特异性。我们进一步证明，钉合BID BH 3的膜靶向优化了其激活BAX的能力，支持BID直接与BAX结合以触发线粒体凋亡的模型。
BAX is a multidomain proapoptotic BCL-2 family protein that resides in the cytosol until activated by an incompletely understood trigger mechanism, which facilitates BAX translocation to mitochondria and downstream death events. Whether BAX is activated by direct contact with select BH3-only members of the BCL-2 family is highly debated. Here we detect and quantify a direct binding interaction between BAX and a hydrocarbon-stapled BID BH3 domain, which triggers the functional activation of BAX at nanomolar doses in vitro. Chemical reinforcement of BID BH3 alpha helicity was required to reveal the direct BID BH3-BAX association. We confirm the specificity of this BH3 interaction by characterizing a stapled BAD BH3 peptide that interacts with antiapoptotic BCL-X-L but does not bind or activate BAX. We further demonstrate that membrane targeting of stapled BID BH3 optimizes its ability to activate BAX, supporting a model in which BID directly engages BAX to trigger mitochondrial apoptosis.