Isoform-and Species-specific Control of Inositol 1,4,5-Trisphosphate (IP3) Receptors by Reactive Oxygen Species
Isoform-and Species-specific Control of Inositol 1,4,5-Trisphosphate (IP3) Receptors by Reactive Oxygen Species
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DOI：
10.1074/jbc.m113.504159
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发表时间：
2014-03-21
影响因子：
4.8
通讯作者：
Hajnoczky, Gyoergy
中科院分区：
文献类型：
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作者：
Bansaghi, Szava;Golenar, Tuende;Hajnoczky, Gyoergy
背景：活性氧（ROS）影响细胞质钙信号。结果如下：超氧阴离子引起IP 3受体的氧化和钙释放的敏化，以促进细胞质钙振荡和线粒体钙摄取。结论：生理相关的ROS通过IP 3受体控制细胞质和线粒体的钙转运。重要性：活性氧（reactive oxygen species，ROS）刺激细胞内[Ca 2 +]（[Ca 2 +]（c））信号，但IP 3受体（IP 3R）在其中的确切作用尚不清楚。IP（3）Rs是内质网和线粒体酶产生ROS的潜在靶点，这可能使IP（3）Rs局部暴露于内质网-线粒体结合处。此外，IP（3）Rs含有多个活性硫醇，它们是ROS的常见分子靶标。因此，我们研究了超氧阴离子（O2）对IP 3R介导的Ca 2+信号转导的影响。在人HepG 2、大鼠RBL-2 H3和鸡DT 40细胞中，我们观察到由O2供体黄嘌呤（X）+黄嘌呤氧化酶（XO）诱发的[Ca 2 +]（c）尖峰和调频振荡，并呈剂量依赖性。[Ca ~（2+）]（c）信号由ER Ca ~（2+）动员介导。X+XO加入透化细胞促进[Ca 2 +]（c）上升诱发的亚最大剂量的IP 3，表明O2直接敏化IP 3R介导的Ca 2+释放。在对X+XO的反应中，表达1型（DKO 1）或2型IP（3）Rs（DKO 2）的三种IP 3R亚型（DKO）中缺少两种的DT 40细胞显示[Ca 2 +]（c）信号，而表达3型IP 3R（DKO 3）的DKO细胞则没有。相比之下，刺激IP 3形成的IgM在每个DKO中引起[Ca 2 +]（c）信号。X+XO还促进了透化DKO 1和DKO 2中次最大IP 3诱发的Ca 2+释放，但在DKO 3或缺乏每一个IP 3R的DT 40（TKO）中无效。然而，X+XO也可以促进用大鼠IP（3）R3转染的TKO中的次优IP 3的作用。尽管计算机模拟研究未能确定鸡IP（3）R3中缺失的巯基，但仅在大鼠IP（3）R3中记录了X+ XO诱导的氧化还原变化。因此，ROS似乎通过IP（3）R内的硫醇基团特异性地敏化IP（3）R，这在鸡IP（3）R3中可能是不可接近的。
Background: Reactive oxygen species (ROS) affect cytoplasmic calcium signaling. Results: Superoxide anion causes oxidation of the IP3 receptor and sensitization of calcium release to promote cytoplasmic calcium oscillations and mitochondrial calcium uptake. Conclusion: Physiologically relevant ROS controls cytoplasmic and mitochondrial calcium transport through IP3 receptors. Significance: Mechanisms of calcium and ROS interactions are relevant for both physiological and pathophysiological signaling.Reactive oxygen species (ROS) stimulate cytoplasmic [Ca2+] ([Ca2+](c)) signaling, but the exact role of the IP3 receptors (IP3R) in this process remains unclear. IP(3)Rs serve as a potential target of ROS produced by both ER and mitochondrial enzymes, which might locally expose IP(3)Rs at the ER-mitochondrial associations. Also, IP(3)Rs contain multiple reactive thiols, common molecular targets of ROS. Therefore, we have examined the effect of superoxide anion (O2) on IP3R-mediated Ca2+ signaling. In human HepG2, rat RBL-2H3, and chicken DT40 cells, we observed [Ca2+](c) spikes and frequency-modulated oscillations evoked by a O2 donor, xanthine (X) + xanthine oxidase (XO), dose-dependently. The [Ca2+](c) signal was mediated by ER Ca2+ mobilization. X+XO added to permeabilized cells promoted the [Ca2+](c) rise evoked by submaximal doses of IP3, indicating that O2 directly sensitizes IP3R-mediated Ca2+ release. In response to X+XO, DT40 cells lacking two of three IP3R isoforms (DKO) expressing either type 1 (DKO1) or type 2 IP(3)Rs (DKO2) showed a [Ca2+](c) signal, whereas DKO expressing type 3 IP3R (DKO3) did not. By contrast, IgM that stimulates IP3 formation, elicited a [Ca2+](c) signal in every DKO. X+XO also facilitated the Ca2+ release evoked by submaximal IP3 in permeabilized DKO1 and DKO2 but was ineffective in DKO3 or in DT40 lacking every IP3R (TKO). However, X+XO could also facilitate the effect of suboptimal IP3 in TKO transfected with rat IP(3)R3. Although in silico studies failed to identify a thiol missing in the chicken IP(3)R3, an X+XO-induced redox change was documented only in the rat IP(3)R3. Thus, ROS seem to specifically sensitize IP(3)Rs through a thiol group(s) within the IP3R, which is probably inaccessible in the chicken IP(3)R3.