Candé Céline, Vahsen Nicola, Kouranti Ilektra, Schmitt Elise, Daugas Eric, Spahr Chris, Luban Jeremy, Kroemer Romano T, Giordanetto Fabrizio, Garrido Carmen, Penninger Josef M, Kroemer Guido
CNRS-UMR8125, Institut Gustave Roussy, Pavillon de Recherche 1, 39 rue Camille-Desmoulins, F-94805 Villejuif, France.
Oncogene. 2004 Feb 26;23(8):1514-21. doi: 10.1038/sj.onc.1207279.
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.
通过质谱分析、免疫共沉淀、下拉实验和分子建模确定亲环素A（CypA）与凋亡诱导因子（AIF）相互作用。在伴随凋亡的染色质浓缩的初始、不依赖半胱天冬酶阶段，发现AIF和CypA在细胞核中共免疫定位。重组AIF和CypA蛋白在体外协同作用于质粒DNA的降解以及诱导纯化细胞核中DNA丢失的能力。AIF和CypA之间的凋亡诱导协同作用不依赖于CypA肽基脯氨酰顺反异构酶活性。在表达Cyp的细胞中，AIF过表达增强凋亡性染色质溶解。与对照相比，AIF依赖性大规模DNA片段化在CypA基因敲除细胞中不太明显。在转染实验中，缺乏CypA结合结构域的AIF突变体是低效的凋亡敏化剂。此外，AIF未能使CypA基因敲除细胞对凋亡诱导敏感，并且通过将CypA基因重新引入CypA缺陷细胞中，AIF反应中的这种缺陷得以逆转。总之，AIF和CypA在染色质溶解中协同作用。
