Department of Biology, University of York, York YO10 5DD, UK; Department of Chemistry and Centre of Excellence in Mass Spectrometry, University of York, York YO10 5DD, UK.
Department of Chemistry and Centre of Excellence in Mass Spectrometry, University of York, York YO10 5DD, UK.
Cell Rep. 2019 Apr 23;27(4):1231-1243.e6. doi: 10.1016/j.celrep.2019.03.107.
The decoration of proteins by carbohydrates is essential for eukaryotic life yet heterogeneous due to a lack of biosynthetic templates. This complex carbohydrate mixture-the glycan profile-is generated in the compartmentalized Golgi, in which level and localization of glycosylation enzymes are key determinants. Here, we develop and validate a computational model for glycan biosynthesis to probe how the biosynthetic machinery creates different glycan profiles. We combined stochastic modeling with Bayesian fitting that enables rigorous comparison to experimental data despite starting with uncertain initial parameters. This is an important development in the field of glycan modeling, which revealed biological insights about the glycosylation machinery in altered cellular states. We experimentally validated changes in N-linked glycan-modifying enzymes in cells with perturbed intra-Golgi-enzyme sorting and the predicted glycan-branching activity during osteogenesis. Our model can provide detailed information on altered biosynthetic paths, with potential for advancing treatments for glycosylation-related diseases and glyco-engineering of cells.
蛋白质的碳水化合物修饰对于真核生物的生命至关重要，但由于缺乏生物合成模板，其具有异质性。这种复杂的碳水化合物混合物——聚糖谱，是在分隔的高尔基体中产生的，其中糖基化酶的水平和定位是关键决定因素。在这里，我们开发并验证了一种用于聚糖生物合成的计算模型，以探究生物合成机制如何创建不同的聚糖谱。我们将随机建模与贝叶斯拟合相结合，即使从不确定的初始参数开始，也能使严格的比较与实验数据进行。这是聚糖建模领域的一个重要发展，揭示了细胞状态改变时糖基化机制的生物学见解。我们通过实验验证了细胞内高尔基体酶分拣受到干扰时 N 连接糖基化修饰酶的变化，以及成骨过程中预测的聚糖分支活性。我们的模型可以提供有关改变的生物合成途径的详细信息，这可能有助于推进糖基化相关疾病的治疗和细胞的糖工程。
