An uncoupling channel within the c-subunit ring of the F1FO ATP synthase is the mitochondrial permeability transition pore
An uncoupling channel within the c-subunit ring of the F1FO ATP synthase is the mitochondrial permeability transition pore
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DOI：
10.1073/pnas.1401591111
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发表时间：
2014-07-22
影响因子：
11.1
通讯作者：
Jonas, Elizabeth A.
中科院分区：
文献类型：
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作者：
Alavian, Kambiz N.;Beutner, Gisela;Jonas, Elizabeth A.
线粒体维持线粒体内膜(IMM)通透性的严密调节，以维持ATP的产生。应激事件导致细胞内钙离子(Ca~(2+))失衡，继而迅速丧失称为通透性转换(PT)的IMM电位，从而导致渗透性变化、代谢功能障碍和细胞死亡。线粒体PT孔(MPTP)的分子同一性以前是未知的。我们发现，F1FO-ATP合成酶FO的纯化重组c-亚单位环形成了一个电压敏感通道，该通道的持续开放导致细胞内IMM的快速和不受控制的去极化。长时间的高Ca~(2+)使ATP合成酶F-1的c-亚单位环变大，并使其脱离亲环素D/环孢素A结合部位，为MPTP的开放提供了一种机制。相反，外源应用于纯化的c-亚基的重组F-1β亚基增加了孔道关闭的可能性。C亚基的缺失减弱了钙离子诱导的IMM去极化，抑制了钙离子和活性氧物种诱导的细胞死亡，而增加c亚基的表达或单通道电导则使死亡变得敏感。我们得出结论，高度调控的c-亚基泄漏通道是MPTP的候选通道。除了细胞死亡，这些发现还暗示，增加健康细胞中c-亚基通道关闭的可能性将增强IMM偶联，提高细胞代谢效率。
Mitochondria maintain tight regulation of inner mitochondrial membrane (IMM) permeability to sustain ATP production. Stressful events cause cellular calcium (Ca2+) dysregulation followed by rapid loss of IMM potential known as permeability transition (PT), which produces osmotic shifts, metabolic dysfunction, and cell death. The molecular identity of the mitochondrial PT pore (mPTP) was previously unknown. We show that the purified reconstituted c-subunit ring of the FO of the F1FO ATP synthase forms a voltage-sensitive channel, the persistent opening of which leads to rapid and uncontrolled depolarization of the IMM in cells. Prolonged high matrix Ca2+ enlarges the c-subunit ring and unhooks it from cyclophilin D/cyclosporine A binding sites in the ATP synthase F-1, providing a mechanism for mPTP opening. In contrast, recombinant F-1 beta-subunit applied exogenously to the purified c-subunit enhances the probability of pore closure. Depletion of the c-subunit attenuates Ca2+-induced IMM depolarization and inhibits Ca2+ and reactive oxygen species-induced cell death whereas increasing the expression or single-channel conductance of the c-subunit sensitizes to death. We conclude that a highly regulated c-subunit leak channel is a candidate for the mPTP. Beyond cell death, these findings also imply that increasing the probability of c-subunit channel closure in a healthy cell will enhance IMM coupling and increase cellular metabolic efficiency.