Ca2+-induced increased lipid packing and domain formation in submitochondrial particles.: A possible early step in the mechanism of Ca2+-stimulated generation of reactive oxygen species by the respiratory chain
Ca2+-induced increased lipid packing and domain formation in submitochondrial particles.: A possible early step in the mechanism of Ca2+-stimulated generation of reactive oxygen species by the respiratory chain
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DOI：
10.1021/bi9828674
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发表时间：
1999-10-05
期刊：
影响因子：
2.9
通讯作者：
Schreier, S
中科院分区：
文献类型：
--
作者：
Grijalba, MT;Vercesi, AE;Schreier, S
线粒体Ca2+和P-i的积累引发了许多改变，导致内膜通透性的非特异性增加[Kowaltowski， a . J., et al.(1996)]。化学通报，2004,26(2):329 - 334。氧化损伤前膜扰动的分子性质尚不清楚。亚线粒体颗粒（SMP）和模型膜中自旋探针的EPR谱表明，Ca2+-心磷脂（CL）络合起重要作用。Ca2+诱导的脂质结构域形成在SMP中检测到，但在有丝质体、SMP提取的脂质或含cl脂质体中检测不到。这些结果被解释为CL与膜蛋白紧密结合，特别是ADP-ATP载体的Ca2+隔离，以及在靠近边界脂质的脂质壳中形成富含ce的强固定化簇。EPR自旋捕获检测到，平面内的脂质和蛋白质重排可能导致琥珀酸补充、抗霉素a中毒的SMP中活性氧的产生增加，有利于碳中心自由基的形成。去除紧密结合的CL也会引起蛋白质聚集，促进分子间硫醇氧化。脂质过氧化也通过氮氧化物EPR谱的消失来监测。在更疏水的环境中，氮氧化物的衰变速度更快，并且被丁基羟基甲苯、EGTA或用Mg2+取代Ca2+抑制。此外，Ca2+引起通透性增加，从呼吸SMP释放羧基荧光素证明。这些结果强烈支持Ca2+与CL结合是Ca2+诱导非特异性线粒体内膜渗透分子机制的早期步骤之一。
Ca2+ and P-i accumulation by mitochondria triggers a number of alterations leading to nonspecific increase in inner membrane permeability [Kowaltowski, A. J., et al. (1996) J. Biol. Chem. 271, 2929-2934]. The molecular nature of the membrane perturbation that precedes oxidative damage is still unknown. EPR spectra of spin probes incorporated in submitochondrial particles (SMP) and in model membranes suggest that Ca2+-cardiolipin (CL) complexation plays an important role. Ca2+-induced lipid domain formation was detected in SMP but not in mitoplasts, in SMP extracted lipids, or in CL-containing liposomes. The results were interpreted in terms of Ca2+ sequestration of CL tightly bound to membrane proteins, in particular the ADP-ATP carrier, and formation of CE-enriched strongly immobilized clusters in lipid shells next to boundary lipid. The in-plane lipid and protein rearrangement is suggested to cause increased reactive oxygen species production in succinate-supplemented, antimycin A-poisoned SMP, favoring the formation of carbon-centered radicals, detected by EPR spin trapping. Removal of tightly bound CL is also proposed to cause protein aggregation, facilitating intermolecular thiol oxidation. Lipid peroxidation was also monitored by the disappearance of the nitroxide EPR spectrum. The decay was faster for nitroxides in a more hydrophobic environment, and was inhibited by butylated hydroxytoluene, by EGTA, or by substituting Mg2+ for Ca2+. In addition, Ca2+ caused an increase in permeability, evidenced by the release of carboxyfluorescein from respiring SMP. The results strongly support Ca2+ binding to CL as one of the early steps in the molecular mechanism of Ca2+-induced nonspecific inner mitochondrial membrane permeabilization.