PARPs transfer ADP-D-ribose to proteins (poly(ADP-ribosyl)ation)

Poly (ADP-ribose) polymerases (PARPs) catalyse the poly(ADP-ribosyl)ation posttranslational modification of proteins. At least 18 human members share homology with the catalytic domain of the founding member, PARP1. PARPs cleave the glycosidic bond of NAD+ between nicotinamide (NAM) and ribose followed by the covalent modification of mainly glutamate residues on acceptor proteins with an ADP-ribosyl unit, with subsequent ADP-ribosyl unit additions linked by glycosidic ribose-ribose bonds. NAM can be utilised in the NAD+ regeneration process. Poly(ADP-ribosyl)ation is important in many biological processess including DNA repair, regulation of chromosome structure, transcriptional regulation, mitosis and apoptosis. PARPs can localise to either the cytosol or the nucleus. The cytosolic PARPs described here are PARP9, PARP10 and PARP16 (Yan et al. 2013, Yu et al. 2005, Di Paolo et al. 2012). PARP4, PARP6, PARP8 and PARP14 may also be located in the cytosol with the same functionality.

多聚(ADP-核糖)聚合酶(PARPs)催化蛋白质的聚(ADP-核糖基)化翻译后修饰。至少18种人类成员与始祖成员PARP1的催化结构域具有同源性。PARPs通过切断烟酰胺(NAM)和核糖之间的NAD+糖苷键，随后通过共价修饰受体蛋白上的谷氨酸残基以ADP-核糖单元进行修饰，随后通过糖苷键将ADP-核糖单元连接。NAM可用于NAD+的再生过程。聚(ADP-核糖基)化在许多生物过程中发挥重要作用，包括DNA修复、染色质结构的调控、转录调控、有丝分裂和细胞凋亡。PARPs可以定位于细胞质或细胞核。本文所描述的细胞质PARPs包括PARP9、PARP10和PARP16（Yan等，2013，Yu等，2005，Di Paolo等，2012）。PARP4、PARP6、PARP8和PARP14也可能位于细胞质，并具有相同的功能。