Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA.
J Biol Chem. 2012 Dec 21;287(52):43527-32. doi: 10.1074/jbc.M112.401141. Epub 2012 Nov 6.
The human ALC1/CHD1L oncogene encodes an SNF2 family ATPase with a macrodomain that binds poly(ADP-ribose) (PAR). We and others previously showed that ALC1 possesses a cryptic ATP-dependent nucleosome remodeling activity that is potently activated in the presence of PARP1 and NAD(+), its substrate for PAR synthesis. In this work, we dissected the mechanism by which PARP1 and NAD(+) activate ALC1 nucleosome remodeling. We demonstrate that ALC1 activation depends on the formation of a stable ALC1·PARylated PARP1·nucleosome intermediate. In addition, by exploiting a novel PAR footprinting assay, we obtained evidence that the ALC1 macrodomain remains stably associated with PAR on autoPARylated PARP1 during the course of nucleosome remodeling reactions. Taken together, our findings are consistent with the model that PAR present on PARylated PARP1 acts as an allosteric effector of ALC1 nucleosome remodeling activity.
人类 ALC1/CHD1L 癌基因编码一种 SNF2 家族 ATP 酶，具有结合多聚（ADP-核糖）（PAR）的宏结构域。我们和其他人之前曾表明，ALC1 具有隐藏的 ATP 依赖性核小体重塑活性，在 PARP1 和 NAD（+）存在下，其 PAR 合成的底物，会被强烈激活。在这项工作中，我们剖析了 PARP1 和 NAD（+）激活 ALC1 核小体重塑的机制。我们证明，ALC1 的激活依赖于稳定的 ALC1·PARylated PARP1·核小体中间产物的形成。此外，通过利用一种新的 PAR 足迹分析测定法，我们获得了证据，即在核小体重塑反应过程中，ALC1 宏结构域在自动 PAR 化的 PARP1 上的 PAR 保持稳定结合。总之，我们的发现与 PAR 存在于 PAR 化的 PARP1 上作为 ALC1 核小体重塑活性的别构效应物的模型一致。
