LETM1-dependent mitochondrial Ca2+ flux modulates cellular bioenergetics and proliferation
LETM1-dependent mitochondrial Ca2+ flux modulates cellular bioenergetics and proliferation
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DOI：
10.1096/fj.14-256453
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发表时间：
2014-11-01
期刊：
影响因子：
4.8
通讯作者：
Madesh, Muniswamy
中科院分区：
文献类型：
--
作者：
Doonan, Patrick J.;Chandramoorthy, Harish C.;Madesh, Muniswamy
线粒体Ca 2+依赖性生物能量学的失调与各种病理生理学环境有关，包括神经变性和心肌梗死。虽然线粒体Ca 2+转运的特点，并已确定了几个分子，包括LETM 1，LETM 1介导的Ca 2+转运的功能作用仍然没有得到解决。本研究探讨了LETM 1介导的线粒体Ca 2+转运和生物能量学在多种细胞类型，包括成纤维细胞来源于患者沃尔夫-赫希霍恩综合征（WHS）。结果表明，线粒体Ca 2+内流和外排率受损LETM 1敲低，并观察到类似的表型EF手，（D 676 A D 688 K）LETM 1突变体过表达的细胞，和来自WHS患者的细胞。虽然LETM 1水平在WHS衍生的成纤维细胞中较低，但线粒体Ca 2+单向转运体组分MCU、MCUR 1和MICU 1保持不变。此外，MCU的线粒体膜片钳电流（I-MCU）在很大程度上不受LETM 1敲低细胞。LETM 1的沉默也可能通过复合物IV失活和ATP产生损害基础线粒体耗氧量。值得注意的是，LETM 1敲低也导致活性氧产生增加。此外，LETM 1沉默促进AMPK活化、自噬和细胞周期停滞。LETM 1或抗氧化剂过表达的重建拯救了线粒体Ca 2+转运和生物能量学。这些发现揭示了LETM 1依赖性线粒体Ca 2+通量在塑造细胞生物能学中的作用。Chandramoorthy，H. C.的方法，霍夫曼，N. E、张，X.，卡德纳斯角，Shanmughapalan，S.，拉詹，S.，Vallem，S.，陈旭，Foskett，J.K.，张振耀，Houser，S. R.，Madesh，M. LETM 1依赖的线粒体Ca 2+通量调节细胞生物能量学和增殖。
Dysregulation of mitochondrial Ca2+-dependent bioenergetics has been implicated in various pathophysiological settings, including neurodegeneration and myocardial infarction. Although mitochondrial Ca2+ transport has been characterized, and several molecules, including LETM1, have been identified, the functional role of LETM1-mediated Ca2+ transport remains unresolved. This study examines LETM1-mediated mitochondrial Ca2+ transport and bioenergetics in multiple cell types, including fibroblasts derived from patients with Wolf-Hirschhorn syndrome (WHS). The results show that both mitochondrial Ca2+ influx and efflux rates are impaired in LETM1 knockdown, and similar phenotypes were observed in EF hand, (D676A D688K)LETM1 mutant-overexpressed cells, and in cells derived from patients with WHS. Although LETM1 levels were lower in WHS-derived fibroblasts, the mitochondrial Ca2+ uniporter components MCU, MCUR1, and MICU1 remain unaltered. In addition, the MCU mitoplast patch-clamp current (I-MCU) was largely unaffected in LETM1-knockdown cells. Silencing of LETM1 also impaired basal mitochondrial oxygen consumption, possibly via complex IV inactivation and ATP production. Remarkably, LETM1 knockdown also resulted in increased reactive oxygen species production. Further, LETM1 silencing promoted AMPK activation, autophagy, and cell cycle arrest. Reconstitution of LETM1 or antioxidant overexpression rescued mitochondrial Ca2+ transport and bioenergetics. These findings reveal the role of LETM1-dependent mitochondrial Ca2+ flux in shaping cellular bioenergetics.Doonan, P J., Chandramoorthy, H. C., Hoffman, N. E., Zhang, X., Cardenas, C., Shanmughapriya, S., Rajan, S., Vallem, S., Chen, X., Foskett, J. K., Cheung, J. Y., Houser, S. R., Madesh, M. LETM1-dependent mitochondrial Ca2+ flux modulates cellular bioenergetics and proliferation.