Loss of the mitochondrial protein Abcb10 results in altered arginine metabolism in MEL and K562 cells and nutrient stress signaling through ATF4.
Loss of the mitochondrial protein Abcb10 results in altered arginine metabolism in MEL and K562 cells and nutrient stress signaling through ATF4.
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DOI：
10.1016/j.jbc.2023.104877
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发表时间：
2023-07
影响因子：
4.8
通讯作者：
Ward, Diane M
中科院分区：
文献类型：
--
作者：
Miljkovic, Marisa;Seguin, Alexandra;Jia, Xuan;Cox, James E;Catrow, Jonathan Leon;Bergonia, Hector;Phillips, John D;Stephens, W Zac;Ward, Diane M
abcb 10是一种参与红细胞血红蛋白化的线粒体膜蛋白。Abcb 10的拓扑结构和ATP酶结构域的定位表明，它出口的底物，可能胆绿素，是必要的血红蛋白化的线粒体。在这项研究中，我们在小鼠红白血病和人红系前体人髓性白血病（K562）细胞中产生了Abcb 10缺失细胞系，以更好地了解Abcb 10缺失的后果。Abcb 10的缺失导致K562和小鼠红白血病细胞在分化后不能血红蛋白化，血红素和中间体卟啉减少，氨基乙酰丙酸合成酶2活性水平降低。代谢组学和转录分析显示，Abcb 10缺失导致细胞精氨酸水平降低，阳离子和中性氨基酸转运蛋白转录物增加，瓜氨酸转化为精氨酸的酶氨基琥珀酸合成酶和氨基琥珀酸裂解酶水平降低。Abcb 10-null细胞中精氨酸水平的降低导致增殖能力的降低。精氨酸补充改善了分化后的Abcb 10无效增殖和血红蛋白化。Abcb 10-null细胞显示真核翻译起始因子2亚基α的磷酸化增加，营养感测转录因子ATF 4和下游靶点DNA损伤诱导转录物3（Chop）、ChaC谷胱甘肽特异性γ-谷氨酰环转移酶1（Chac 1）和γ-谷氨酰-tRNA合成酶1（Rars）的表达增加。这些结果表明，当Abcb 10底物被困在线粒体中时，营养传感机制被打开，重塑转录，以阻断红细胞模型中增殖和血红蛋白生物合成所必需的蛋白质合成。
Abcb10 is a mitochondrial membrane protein involved in hemoglobinization of red cells. Abcb10 topology and ATPase domain localization suggest it exports a substrate, likely biliverdin, out of mitochondria that is necessary for hemoglobinization. In this study, we generated Abcb10 deletion cell lines in both mouse murine erythroleukemia and human erythroid precursor human myelogenous leukemia (K562) cells to better understand the consequences of Abcb10 loss. Loss of Abcb10 resulted in an inability to hemoglobinize upon differentiation in both K562 and mouse murine erythroleukemia cells with reduced heme and intermediate porphyrins and decreased levels of aminolevulinic acid synthase 2 activity. Metabolomic and transcriptional analyses revealed that Abcb10 loss gave rise to decreased cellular arginine levels, increased transcripts for cationic and neutral amino acid transporters with reduced levels of the citrulline to arginine converting enzymes argininosuccinate synthetase and argininosuccinate lyase. The reduced arginine levels in Abcb10-null cells gave rise to decreased proliferative capacity. Arginine supplementation improved both Abcb10-null proliferation and hemoglobinization upon differentiation. Abcb10-null cells showed increased phosphorylation of eukaryotic translation initiation factor 2 subunit alpha, increased expression of nutrient sensing transcription factor ATF4 and downstream targets DNA damage inducible transcript 3 (Chop), ChaC glutathione specific gamma-glutamylcyclotransferase 1 (Chac1), and arginyl-tRNA synthetase 1 (Rars). These results suggest that when the Abcb10 substrate is trapped in the mitochondria, the nutrient sensing machinery is turned on remodeling transcription to block protein synthesis necessary for proliferation and hemoglobin biosynthesis in erythroid models.