Intracellular oxygen determined by respiration regulates localization of Ras and prenylated proteins.
Intracellular oxygen determined by respiration regulates localization of Ras and prenylated proteins.
复制标题
由呼吸决定的细胞内氧调节 Ras 和异戊二烯化蛋白的定位。
DOI：
10.1038/cddis.2015.64
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发表时间：
2015
影响因子：
9
通讯作者：
Higuchi,M
中科院分区：
文献类型：
--
作者：
Kim,A;Davis,R;Higuchi,M
线粒体DNA（mtDNA）含量的减少诱导氧化磷酸化的减少和对发酵糖酵解的依赖，即瓦尔堡效应。在侵袭性前列腺癌（PCa）中，mtDNA的减少了氧消耗，增加了细胞内氧浓度，并诱导Ras的组成性激活。许多细胞死亡、生长、分化和发育所必需的蛋白质，如Ras，需要异戊烯化以进行亚细胞定位和活化。蛋白质的异戊烯化被定义为类异戊二烯在C-末端或其附近与半胱氨酸残基的连接。3-羟基-3-甲基-戊二酰-辅酶A还原酶（HMGR）产生类异戊二烯，并受氧的后向调节。我们研究了细胞内氧在异戊二烯化蛋白质膜定位中的关键作用。在低分化PCa（PC-3）和高分化PCa（LNCaP）细胞中观察到异戊二烯化蛋白（H-Ras、前层蛋白A/C和Rab5a）的定位。PC-3细胞表现出高的细胞内氧浓度，和H-Ras，prelamin A/C，和Rab5a定位于各种膜（高尔基体和质膜，核膜，和早期内涵体，分别）。值得注意的是，外源性缺氧（0.2%O2）在PC-3细胞诱导细胞内缺氧和改变的异戊二烯化蛋白的定位。H-Ras和Rab5a易位到胞浆中，前核纤层蛋白A/C在核内形成异常核膜。甲羟戊酸逆转了该定位，表明甲羟戊酸途径参与。相反，在LNCaP细胞中，表现出低的细胞内氧浓度，H-Ras和Rab5a定位在胞质溶胶中，并且前层蛋白A/C在核内形成不充分的核膜。外源性高氧（40%O2）使细胞内氧浓度增加，并诱导Ras从胞浆向膜转位。前体蛋白A/C转位到核膜上形成核膜。Rab5a转位到早期内体。异戊烯化蛋白的特异性定位依赖于细胞内氧浓度。这些结果表明，细胞内氧浓度调节异戊二烯化蛋白的定位和激活。
Reduction of mitochondrial DNA (mtDNA) content induces the reduction of oxidative phosphorylation and dependence on fermentative glycolysis, that is, the Warburg effect. In aggressive prostate cancer (PCa), the reduction of mtDNA reduces oxygen consumption, increases intracellular oxygen concentration, and induces constitutive activation of Ras. Many essential proteins for cell death, growth, differentiation, and development, such as Ras, require prenylation for subcellular localization and activation. Prenylation of a protein is defined as the attachment of isoprenoids to a cysteine residue at or near the C-terminus. 3-Hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGR) produces isoprenoids, and is posttranslationally regulated by oxygen. We investigated a critical role of intracellular oxygen in membrane localization of prenylated proteins. Localization of prenylated proteins (H-Ras, prelamin A/C, and Rab5a) was observed in poorly differentiated PCa (PC-3) and well-differentiated PCa (LNCaP) cells. PC-3 cells exhibited high intracellular oxygen concentration, and H-Ras, prelamin A/C, and Rab5a were localized to various membranes (Golgi and plasma membrane, nuclear membrane, and early endosomes, respectively). Remarkably, exogenous hypoxia (0.2% O 2) in PC-3 cells induced intracellular hypoxia and changed the localization of the prenylated proteins. H-Ras and Rab5a were translocated to cytosol, and prelamin A/C was in the nucleus forming an abnormal nuclear envelope. The localization was reversed by mevalonate indicating the involvement of mevalonate pathway. In contrast, in LNCaP cells, exhibiting low intracellular oxygen concentration, H-Ras and Rab5a were localized in the cytosol, and prelamin A/C was inside the nucleus forming an inadequate nuclear envelope. Exogenous hyperoxia (40% O 2) increased the intracellular oxygen concentration and induced Ras translocation from cytosol to the membrane. Prelamin A/C was translocated to the nuclear membrane and formed a proper nuclear envelope. Rab5a was translocated to the early endosomes. The specific localizations of the prenylated proteins were dependent on intracellular oxygen concentration. These results demonstrate that intracellular oxygen concentration regulates the localization and activation of prenylated proteins.