Poly(ADP-ribose) polymerase 14 (PARP14) is a member of the PARP family of enzymes that transfer ADP-ribose from NAD⁺ to nucleophilic amino acids on target proteins, a process known as mono-ADP-ribosylation (MARylation). PARP14 is involved in normal immune function through the IL-4 signaling pathway and is a prosurvival factor in multiple myeloma and hepatocellular carcinoma. A mechanistic understanding of the physiological and pathophysiological roles of PARP14 has been limited by the dearth of PARP14-specific MARylation targets. Herein we engineered a PARP14 variant that uses an NAD⁺ analog that is orthogonal to wild-type PARPs for identifying PARP14-specific MARylation targets. Combining this chemical genetics approach with a BioID approach for proximity-dependent labeling of PARP14 interactors, we identified 114 PARP14-specific protein substrates, several of which are RNA regulatory proteins. One of these targets is PARP13, a protein known to play a role in regulating RNA stability. PARP14 MARylates PARP13 on several acidic amino acids. This study not only reveals crosstalk among PARP family members but also highlights the advantage of using disparate approaches for identifying the direct targets of individual PARP family members.

中文翻译：

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化学遗传学与接近性依赖标记相结合揭示了聚（ADP-核糖）聚合酶14（PARP14）的细胞靶标。

聚（ADP-核糖）聚合酶14（PARP14）是PARP家族的一员，该酶可将ADP-核糖从NAD ⁺转移到靶蛋白的亲核氨基酸上，这一过程称为单ADP-核糖基化（MARylation）。PARP14通过IL-4信号通路参与正常的免疫功能，是多发性骨髓瘤和肝细胞癌的生存因素。对PARP14的生理和病理生理作用的机械理解受到PARP14特定MARylation目标的缺乏的限制。在这里，我们设计了使用NAD ⁺的PARP14变体与野生型PARP正交的类似物，用于识别PARP14特定的MARylation目标。结合此化学遗传学方法与BioID方法进行PARP14相互作用子的邻近依赖性标记，我们鉴定了114种PARP14特异性蛋白底物，其中一些是RNA调节蛋白。这些靶标之一是PARP13，一种已知在调节RNA稳定性中起作用的蛋白质。PARP14 MARP使PARP13在几个酸性氨基酸上形成。这项研究不仅揭示了PARP家族成员之间的串扰，而且强调了使用不同方法来识别单个PARP家族成员的直接目标的优势。