Piirainen Mari A, Frey Alexander D
Department of Bioproducts and Biosystems, Aalto University, Espoo, Finland.
Kemistintie 1, Aalto University, Otakaari, Finland.
Front Mol Biosci. 2022 Jun 2;9:910709. doi: 10.3389/fmolb.2022.910709. eCollection 2022.
Yeasts are widely used and established production hosts for biopharmaceuticals. Despite of tremendous advances on creating human-type N-glycosylation, N-glycosylated biopharmaceuticals manufactured with yeasts are missing on the market. The N-linked glycans fulfill several purposes. They are essential for the properties of the final protein product for example modulating half-lives or interactions with cellular components. Still, while the protein is being formed in the endoplasmic reticulum, specific glycan intermediates play crucial roles in the folding of or disposal of proteins which failed to fold. Despite of this intricate interplay between glycan intermediates and the cellular machinery, many of the glycoengineering approaches are based on modifications of the N-glycan processing steps in the endoplasmic reticulum (ER). These N-glycans deviate from the canonical structures required for interactions with the lectins of the ER quality control system. In this review we provide a concise overview on the N-glycan biosynthesis, glycan-dependent protein folding and quality control systems and the wide array glycoengineering approaches. Furthermore, we discuss how the current glycoengineering approaches partially or fully by-pass glycan-dependent protein folding mechanisms or create structures that mimic the glycan epitope required for ER associated protein degradation.
酵母是生物制药领域广泛应用且成熟的生产宿主。尽管在构建人源型N - 糖基化方面取得了巨大进展，但市场上仍缺少用酵母生产的N - 糖基化生物制药产品。N - 连接聚糖具有多种功能。它们对于最终蛋白质产品的性质至关重要，例如调节半衰期或与细胞成分的相互作用。尽管如此，当蛋白质在内质网中形成时，特定的聚糖中间体在蛋白质折叠或对未折叠蛋白质的处理中起着关键作用。尽管聚糖中间体与细胞机制之间存在这种复杂的相互作用，但许多糖基工程方法都是基于对内质网（ER）中N - 聚糖加工步骤的修饰。这些N - 聚糖偏离了与ER质量控制系统凝集素相互作用所需的典型结构。在本综述中，我们简要概述了N - 聚糖生物合成、聚糖依赖性蛋白质折叠和质量控制系统以及广泛的糖基工程方法。此外，我们讨论了当前的糖基工程方法如何部分或完全绕过聚糖依赖性蛋白质折叠机制，或创建模仿ER相关蛋白质降解所需聚糖表位的结构。
