Discovery of a nucleocytoplasmic O-mannose glycoproteome in yeast
Discovery of a nucleocytoplasmic O-mannose glycoproteome in yeast
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DOI：
10.1073/pnas.1511743112
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发表时间：
2015-12-22
影响因子：
11.1
通讯作者：
Clausen, Henrik
中科院分区：
文献类型：
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作者：
Halim, Adnan;Larsen, Ida Signe Bohse;Clausen, Henrik
N-乙酰氨基葡萄糖(GlcNAc)在丝氨酸和苏氨酸残基上的动态循环(O-GlcN酰化)是除酵母以外的所有真核细胞中必不可少的过程，包括酿酒酵母和裂殖酵母。O-GlcN酰化在与蛋白质磷酸化的复杂相互作用中调节信号和细胞过程，并通过将氨基己糖的生物合成途径与细胞信号联系起来作为营养物质的关键传感器。一个长期存在的难题是，鉴于酵母类似的磷酸化信号系统，酵母如何在没有O-GlcN酰化的情况下生存下来。我们以前开发了一种灵敏的凝集素浓缩和质谱仪工作流程，用于鉴定人类O-连接甘露糖(O-Man)糖蛋白质组，并利用这一工作流程在人类细胞系中鉴定O-Man糖蛋白的胸膜，包括钙粘附素和原钙粘附素的大家族。在这里，我们将工作流程应用于酵母，目的是鉴定酵母O-Man糖蛋白组，在这样做的过程中，我们在酿酒酵母和S.pombe的核蛋白、细胞质蛋白和线粒体蛋白上发现了迄今未知的O-Man糖基。在我们对人类细胞系的分析中，没有发现这种O-Man糖蛋白。然而，酵母O-Man核质蛋白的类型和已鉴定的O-Man残基的定位反映了在其他真核细胞中发现的O-GlcNAc糖蛋白组，表明这两种不同类型的O-糖基化具有相同的重要生物学功能。这一发现开启了对酶机制的探索，预计酶机制将调节核质O-Man糖基化。这种O-Man糖基化的操作很有可能在酵母生物加工中有广泛的应用。
Dynamic cycling of N-Acetylglucosamine (GlcNAc) on serine and threonine residues (O-GlcNAcylation) is an essential process in all eukaryotic cells except yeast, including Saccharomyces cerevisiae and Schizosaccharomyces pombe. O-GlcNAcylation modulates signaling and cellular processes in an intricate interplay with protein phosphorylation and serves as a key sensor of nutrients by linking the hexosamine biosynthetic pathway to cellular signaling. A longstanding conundrum has been how yeast survives without O-GlcNAcylation in light of its similar phosphorylation signaling system. We previously developed a sensitive lectin enrichment and mass spectrometry workflow for identification of the human O-linked mannose (O-Man) glycoproteome and used this to identify a pleothora of O-Man glycoproteins in human cell lines including the large family of cadherins and protocadherins. Here, we applied the workflow to yeast with the aim to characterize the yeast O-Man glycoproteome, and in doing so, we discovered hitherto unknown O-Man glycosites on nuclear, cytoplasmic, and mitochondrial proteins in S. cerevisiae and S. pombe. Such O-Man glycoproteins were not found in our analysis of human cell lines. However, the type of yeast O-Man nucleocytoplasmic proteins and the localization of identified O-Man residues mirror that of the O-GlcNAc glycoproteome found in other eukaryotic cells, indicating that the two different types of O-glycosylations serve the same important biological functions. The discovery opens for exploration of the enzymatic machinery that is predicted to regulate the nucleocytoplasmic O-Man glycosylations. It is likely that manipulation of this type of O-Man glycosylation will have wide applications for yeast bioprocessing.