AIF and cyclophilin A cooperate in apoptosis-associated chromatinolysis
AIF and cyclophilin A cooperate in apoptosis-associated chromatinolysis
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DOI：
10.1038/sj.onc.1207279
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发表时间：
2004-02-26
期刊：
影响因子：
8
通讯作者：
Kroemer, G
中科院分区：
文献类型：
--
作者：
Candé, C;Vahsen, N;Kroemer, G
亲环素A(CypA)与细胞凋亡诱导因子(AIF)的相互作用通过质谱学、免疫共沉淀、下拉实验和分子模拟确定。在伴随细胞凋亡的染色质凝聚的不依赖于caspase的初始阶段，发现AIF和CypA共免疫定位于细胞核。重组AIF和CypA蛋白在体外协同降解质粒DNA，以及在纯化的细胞核中诱导DNA丢失的能力。AIF与CypA之间的协同作用不依赖于CypA肽基-脯氨酰顺式-反式异构酶的活性。在Cyp表达的细胞中，AIF的过表达促进了细胞凋亡的染色质溶解。与对照组相比，CypA基因敲除细胞中依赖于AIF的大规模DNA片段化不那么明显。在转染实验中，缺乏CypA结合域的AIF突变体是低效的细胞凋亡敏感剂。此外，AIF未能使CypA基因敲除细胞对凋亡诱导敏感，这一缺陷可通过将CypA基因重新导入CypA缺陷细胞而被逆转。综上所述，AIF和CypA在染色质分解过程中协同工作。
Cyclophilin A (CypA) was determined to interact with apoptosis-inducing factor (AIF) by mass spectroscopy, coimmunoprecipitation, pull-down assays, and molecular modeling. During the initial, caspase-independent stage of chromatin condensation that accompanies apoptosis, AIF and CypA were found to coimmunolocalize in the nucleus. Recombinant AIF and CypA proteins synergized in vitro in the degradation of plasmid DNA, as well as in the capacity to induce DNA loss in purified nuclei. The apoptogenic cooperation between AIF and CypA did not rely on the CypA peptidyl-prolyl cis-trans isomerase activity. In Cyp-expressing cells, AIF overexpression augmented apoptotic chromatinolysis. The AIF-dependent large-scale DNA fragmentation was less pronounced in CypA knockout cells as compared to controls. AIF mutants lacking the CypA-binding domain were inefficient apoptosis sensitizers in transfection experiments. Moreover, AIF failed to sensitize CypA knockout cells to apoptosis induction, and this defect in the AIF response was reversed by reintroduction of the CypA gene into CypA-deficient cells. In summary, AIF and CypA collaborate in chromatinolysis.