Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Department of Chemical and Biological Engineering and Center for Synthetic Biology, Northwestern University, Evanston, IL, 60208, USA.
Nat Commun. 2022 Oct 21;13(1):6257. doi: 10.1038/s41467-022-33806-8.
Mucin-type-O-glycosylation on proteins is integrally involved in human health and disease and is coordinated by an enzyme family of 20 N-acetylgalactosaminyltransferases (GalNAc-Ts). Detailed knowledge on the biological effects of site-specific O-glycosylation is limited due to lack of information on specific glycosylation enzyme activities and O-glycosylation site-occupancies. Here we present a systematic analysis of the isoform-specific targets of all GalNAc-Ts expressed within a tissue-forming human skin cell line, and demonstrate biologically significant effects of O-glycan initiation on epithelial formation. We find over 300 unique glycosylation sites across a diverse set of proteins specifically regulated by one of the GalNAc-T isoforms, consistent with their impact on the tissue phenotypes. Notably, we discover a high variability in the O-glycosylation site-occupancy of 70 glycosylated regions of secreted proteins. These findings revisit the relevance of individual O-glycosylation sites in the proteome, and provide an approach to establish which sites drive biological functions.
蛋白质上的粘蛋白型-O-糖基化与人类健康和疾病息息相关，由 20 种 N-乙酰半乳糖胺转移酶（GalNAc-Ts）组成的酶家族协调完成。由于缺乏特定糖基化酶活性和 O-糖基化位点占有率的信息，因此对特定位点-O-糖基化的生物学效应的了解十分有限。在这里，我们对在组织形成的人类皮肤细胞系中表达的所有 GalNAc-T 的同工型特异性靶标进行了系统分析，并证明了 O-聚糖起始对上皮形成的生物学意义。我们发现，在一组多样化的蛋白质中，有超过 300 个独特的糖基化位点受到其中一种 GalNAc-T 同工型的特异性调控，这与它们对组织表型的影响一致。值得注意的是，我们发现 70 个分泌蛋白的糖基化区域的 O-糖基化位点占有率存在高度变异性。这些发现重新审视了蛋白质组中各个 O-糖基化位点的相关性，并提供了一种确定哪些位点驱动生物学功能的方法。
