人APOBEC3酶是单链(ss)DNA和RNA胞苷脱氨酶家族,其作为针对病毒和逆转录元件的固有免疫的一部分。这些酶使胞嘧啶脱氨基以形成尿嘧啶,尿嘧啶可以在功能上失活或引起病毒或逆转录元件基因组的降解。此外,APOBEC3通过蛋白质和核酸相互作用具有非脱氨作用的抗病毒活性。如果表达水平失调,一些APOBEC3酶可以进入人类基因组,导致脱氨和诱变,有助于癌症的发生和进化。虽然已知APOBEC3酶与大核糖核蛋白复合物相互作用,功能和RNA依赖性尚未完全了解。为了进一步了解它们的细胞作用,我们通过亲和纯化质谱(AP-MS)确定了人类APOBEC3酶的蛋白质相互作用网络,并绘制了一组不同的蛋白质-蛋白质和蛋白质-RNA介导的相互作用。我们的分析确定了APOBEC3C之间的新型RNA介导的相互作用,APOBEC3H单倍型I和II,和带有剪接体蛋白的APOBEC3G,以及APOBEC3G和APOBEC3H单倍型I,其蛋白质参与tRNA甲基化和ncRNA从细胞核输出。此外,我们鉴定了不依赖RNA的蛋白质-蛋白质与APOBEC3B的相互作用,APOBEC3D,和APOBEC3F和蛋白质折叠伴侣的prefoldin家族。prefoldin5(PFD5)和APOBEC3B之间的相互作用破坏了PFD5诱导癌基因cMyc降解的能力,在癌症中涉及APOBEC3B蛋白相互作用网络。总之,结果揭示了APOBEC3家族的新功能和相互作用,并表明它们可能在细胞RNA生物学中具有基本作用,它们的蛋白质-蛋白质相互作用不是多余的,与肿瘤抑制因子有蛋白质-蛋白质相互作用,表明在癌症生物学中的作用。数据可通过具有标识符PXD044275的ProteomeXchange获得。
Human
APOBEC3 enzymes are a family of single-stranded (ss)DNA and RNA cytidine deaminases that act as part of the intrinsic immunity against viruses and retroelements. These enzymes deaminate cytosine to form uracil which can functionally inactivate or cause degradation of viral or retroelement genomes. In addition, APOBEC3s have deamination-independent antiviral activity through protein and nucleic acid interactions. If expression levels are misregulated, some
APOBEC3 enzymes can access the human genome leading to deamination and mutagenesis, contributing to cancer initiation and evolution. While
APOBEC3 enzymes are known to interact with large ribonucleoprotein complexes, the function and RNA dependence are not entirely understood. To further understand their cellular roles, we determined by affinity purification mass spectrometry (AP-MS) the protein interaction network for the human
APOBEC3 enzymes and mapped a diverse set of protein-protein and protein-RNA mediated interactions. Our analysis identified novel RNA-mediated interactions between APOBEC3C, APOBEC3H Haplotype I and II, and APOBEC3G with spliceosome proteins, and APOBEC3G and APOBEC3H Haplotype I with proteins involved in tRNA methylation and ncRNA export from the nucleus. In addition, we identified RNA-independent protein-protein interactions with APOBEC3B, APOBEC3D, and APOBEC3F and the prefoldin family of protein-folding chaperones. Interaction between prefoldin 5 (PFD5) and APOBEC3B disrupted the ability of PFD5 to induce degradation of the oncogene cMyc, implicating the APOBEC3B protein interaction network in cancer. Altogether, the results uncover novel functions and interactions of the
APOBEC3 family and suggest they may have fundamental roles in cellular RNA biology, their protein-protein interactions are not redundant, and there are protein-protein interactions with tumor suppressors, suggesting a role in cancer biology. Data are available via ProteomeXchange with the identifier PXD044275.