Deconstruction of O-glycosylation-GalNAc-T isoforms direct distinct subsets of the O-glycoproteome
Deconstruction of O-glycosylation-GalNAc-T isoforms direct distinct subsets of the O-glycoproteome
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DOI：
10.15252/embr.201540796
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发表时间：
2015-12-01
期刊：
影响因子：
7.7
通讯作者：
Clausen, Henrik
中科院分区：
文献类型：
--
作者：
Schjoldager, Katrine T.;Joshi, Hiren J.;Clausen, Henrik
在后生动物细胞中，大多数通过分泌途径转运的蛋白质都存在galnac型o -糖基化。o -糖蛋白组受多达20种多肽GalNAc-Ts的调控，目前对GalNAc-Ts的作用和生物学功能了解甚少。在这里，我们使用锌指核酸酶（ZFN）定向敲除策略来探测肝细胞中主要GalNAc-Ts （GalNAc-T1和GalNAc-T2）的贡献，并探索GalNAc-T库如何定量影响o糖蛋白组。我们证明大部分o -糖蛋白组被冗余覆盖，而底物的不同亚群被GalNAc-T1和GalNAc-T2的非冗余功能修饰。每个异构体的非冗余o糖蛋白组亚群和特异性转录反应与不同的细胞过程有关；对于GalNAc-T2亚型，这些支持在脂质代谢中的作用。结果表明GalNAc-Ts具有不同的非冗余糖基化功能，可能影响不同的细胞过程。该数据可作为独特GalNAc-T底物的综合资源。我们的研究为o -糖蛋白组的差异调控提供了新的视角，表明GalNAc-Ts的多样性是为了调节不同的蛋白质功能和细胞过程而产生的。
GalNAc-type O-glycosylation is found on most proteins trafficking through the secretory pathway in metazoan cells. The O-glycoproteome is regulated by up to 20 polypeptide GalNAc-Ts and the contributions and biological functions of individual GalNAc-Ts are poorly understood. Here, we used a zinc-finger nuclease (ZFN)-directed knockout strategy to probe the contributions of the major GalNAc-Ts (GalNAc-T1 and GalNAc-T2) in liver cells and explore how the GalNAc-T repertoire quantitatively affects the O-glycoproteome. We demonstrate that the majority of the O-glycoproteome is covered by redundancy, whereas distinct subsets of substrates are modified by non-redundant functions of GalNAc-T1 and GalNAc-T2. The non-redundant O-glycoproteome subsets and specific transcriptional responses for each isoform are related to different cellular processes; for the GalNAc-T2 isoform, these support a role in lipid metabolism. The results demonstrate that GalNAc-Ts have different non-redundant glycosylation functions, which may affect distinct cellular processes. The data serves as acomprehensive resource for unique GalNAc-T substrates. Our study provides a new view of the differential regulation of the O-glycoproteome, suggesting that the plurality of GalNAc-Ts arose to regulate distinct protein functions and cellular processes.