APLF (C2orf13) is a novel component of poly(ADP-ribose) signaling in mammalian cells
APLF (C2orf13) is a novel component of poly(ADP-ribose) signaling in mammalian cells
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DOI：
10.1128/mcb.02243-07
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发表时间：
2008-07-01
影响因子：
5.3
通讯作者：
Caldecott, Keith W.
中科院分区：
文献类型：
--
作者：
Rulten, Stuart L.;Cortes-Ledesma, Felipe;Caldecott, Keith W.
APLF是一种新的功能未知的蛋白质，通过与XRCC1和XRCC4的FHA结构域的相互作用，聚集在染色体DNA链断裂的位置。APLF还可以通过一种未知的机制在染色体DNA链断裂的位置积累，而不是通过FHA结构域，该机制需要一个高度保守的C末端串联锌指结构域。在这里，我们证明了锌指结构域与聚(ADP-核糖)紧密结合，聚(ADP-核糖)是一种在染色体损伤部位瞬时合成的聚合物翻译后修饰，以加速DNA链断裂修复反应。蛋白质多聚(ADP-核糖基)受到严格调控，其合成或降解的缺陷减缓了染色体单链断裂修复的整体速度。有趣的是，APLF在体外对聚(ADP-核糖基)产生负面影响，这种活性依赖于它与聚合物结合的能力。此外，在人A549细胞中瞬时过表达全长APLF或编码串联锌指结构域的C-末端片段极大地抑制了聚(ADP-核糖)的出现，这是一种锌指依赖的方式。我们认为，APLF可以通过锌指与多聚ADP-核糖结合在染色体损伤部位聚集，是哺乳动物细胞中多聚ADP-核糖信号的新成分。
APLF is a novel protein of unknown function that accumulates at sites of chromosomal DNA strand breakage via forkhead-associated (FHA) domain-mediated interactions with XRCC1 and XRCC4. APLF can also accumulate at sites of chromosomal DNA strand breaks independently of the FHA domain via an unidentified mechanism that requires a highly conserved C-terminal tandem zinc finger domain. Here, we show that the zinc finger domain binds tightly to poly (ADP-ribose), a polymeric posttranslational modification synthesized transiently at sites of chromosomal damage to accelerate DNA strand break repair reactions. Protein poly (ADP-ribosyl)ation is tightly regulated and defects in either its synthesis or degradation slow global rates of chromosomal single-strand break repair. Interestingly, APLF negatively affects poly(ADP-ribosyl)ation in vitro, and this activity is dependent on its capacity to bind the polymer. In addition, transient overexpression in human A549 cells of full-length APLF or a C-terminal fragment encoding the tandem zinc finger domain greatly suppresses the appearance of poly(ADP-ribose), in a zinc finger-dependent manner. We conclude that APLF can accumulate at sites of chromosomal damage via zinc finger-mediated binding to poly(ADP-ribose) and is a novel component of poly(ADP-ribose) signaling in mammalian cells.