GSK3 inactivation is involved in mitochondrial complex IV defect in transforming growth factor (TGF) β1-induced senescence
GSK3 inactivation is involved in mitochondrial complex IV defect in transforming growth factor (TGF) β1-induced senescence
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DOI：
10.1016/j.yexcr.2012.04.012
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发表时间：
2012-09-10
影响因子：
3.7
通讯作者：
Yoon, Gyesoon
中科院分区：
文献类型：
--
作者：
Byun, Hae-Ok;Jung, Hyun-Jung;Yoon, Gyesoon
转化生长因子 β 1 (TGF β 1) 通过降低复合物 IV 活性持续产生线粒体活性氧 (ROS)，从而诱导 Mv1Lu 细胞衰老。在这里，我们研究了 TGF beta 1 对线粒体复合物 IV 活性影响的分子机制。 TGF beta 1 逐渐磷酸化糖原合酶激酶 3 (GSK3) α 和 β 1 的负调控位点，与细胞内 ROS 生成谱很好地对应。 N-乙酰半胱氨酸（一种抗氧化剂）的预处理不会改变 GSK3 磷酸化（失活），而 SB415286 对 GSK3 的药理学抑制显着增加线粒体 ROS，这意味着 GSK3 磷酸化是 ROS 生成的上游事件。 SB415286 抑制 GSK3 会降低复合物 IV 活性和细胞 O-2 消耗率，并最终诱导 Mv1Lu 细胞衰老。 siRNA 介导的 GSK3 敲低也获得了类似的结果。此外，我们发现GSK3不仅存在于细胞质中，还存在于Mv1Lu细胞的线粒体中，线粒体GSK3结合复合体IV亚基6b，该亚基没有电子载体，拓扑位于线粒体膜间隙中。通过 siRNA 介导的亚基 6b 敲低，证明了亚基 6b 参与控制复合物 IV 活性和总体呼吸速率。最后，TGF beta 1 处理降低了亚基 6b 与 GSK3 的结合以及亚基 6b 磷酸化。综上所述，我们的结果表明，GSK3 失活通过减少亚基 6b 的磷酸化，在 TGF beta 1 诱导的复合物 IV 缺陷中发挥重要作用，从而有助于衰老相关的线粒体 ROS 的产生。 (C) 2012 Elsevier Inc. 保留所有权利。
Transforming growth factor beta 1 (TGF beta 1) induces Mv1Lu cell senescence by persistently producing mitochondrial reactive oxygen species (ROS) through decreased complex IV activity. Here, we investigated the molecular mechanism underlying the effect of TGF beta 1 on mitochondrial complex IV activity. TGF beta 1 progressively phosphorylated the negative regulatory sites of both glycogen synthase kinase 3 (GSK3) alpha and beta 1, corresponding well to the intracellular ROS generation profile. Pre-treatment of N-acetyl cysteine, an antioxidant, did not alter this GSK3 phosphorylation (inactivation), whereas pharmacological inhibition of GSK3 by SB415286 significantly increased mitochondrial ROS, implying that GSK3 phosphorylation is an upstream event of the ROS generation. GSK3 inhibition by SB415286 decreased complex IV activity and cellular O-2 consumption rate and eventually induced senescence of Mv1Lu cell. Similar results were obtained with siRNA-mediated knockdown of GSK3. Moreover, we found that GSK3 not only exists in cytosol but also in mitochondria of Mv1Lu cell and the mitochondrial GSK3 binds complex IV subunit 6b which has no electron carrier and is topologically located in the mitochondrial intermembrane space. Involvement of subunit 6b in controlling complex IV activity and overall respiration rate was proved with siRNA-mediated knockdown of subunit 6b. Finally, TGF beta 1 treatment decreased the binding of the subunit 6b to GSK3 and subunit 6b phosphorylation. Taken together, our results suggest that GSK3 inactivation is importantly involved in TGF beta 1-induced complex IV defects through decreasing phosphorylation of the subunit 6b, thereby contributing to senescence-associated mitochondrial ROS generation. (C) 2012 Elsevier Inc. All rights reserved.