PARP-7 (TiPARP) is a mono(ADP-ribosyl) transferase whose proteins substrates and biological activities are poorly understood. We observed that PARP7 mRNA levels are lower in ovarian cancer patient samples compared to non-cancerous tissue, but PARP-7 protein nonetheless contributes to several cancer-related biological endpoints in ovarian cancer cells (e.g., growth, migration). Global gene expression analyses in ovarian cancer cells subjected to PARP-7 depletion indicate biological roles for PARP-7 in cell-cell adhesion and gene regulation. To identify the MARylated substrates of PARP-7 in ovarian cancer cells, we developed an NAD+ analog-sensitive approach, which we coupled with mass spectrometry to identify the PARP-7 ADP-ribosylated proteome in ovarian cancer cells, including cell-cell adhesion and cytoskeletal proteins. Specifically, we found that PARP-7 MARylates α-tubulin to promote microtubule instability, which may regulate ovarian cancer cell growth and motility. In sum, we identified an extensive PARP-7 ADP-ribosylated proteome with important roles in cancer-related cellular phenotypes.

中文翻译：

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PARP-7 底物的鉴定揭示了 MARylation 在卵巢癌细胞微管控制中的作用


PARP-7 (TiPARP) 是一种单 (ADP-核糖基) 转移酶，其蛋白质底物和生物活性知之甚少。我们观察到，与非癌组织相比，卵巢癌患者样本中的 PARP7 mRNA 水平较低，但 PARP-7 蛋白仍然有助于卵巢癌细胞中的几个与癌症相关的生物学终点（例如生长、迁移）。 PARP-7 耗竭的卵巢癌细胞的整体基因表达分析表明 PARP-7 在细胞间粘附和基因调控中的生物学作用。为了鉴定卵巢癌细胞中 PARP-7 的 MARylated 底物，我们开发了一种 NAD+ 类似物敏感方法，将其与质谱联用来鉴定卵巢癌细胞中的 PARP-7 ADP-核糖基化蛋白质组，包括细胞间粘附和细胞骨架蛋白。具体来说，我们发现 PARP-7 MArylate α-微管蛋白可促进微管不稳定，这可能调节卵巢癌细胞的生长和运动。总之，我们鉴定了广泛的 PARP-7 ADP 核糖基化蛋白质组，在癌症相关细胞表型中具有重要作用。