Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA.
Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA.
Curr Opin Struct Biol. 2019 Jun;56:78-86. doi: 10.1016/j.sbi.2018.12.005. Epub 2019 Jan 26.
Fucose is a common terminal modification on protein and lipid glycans. Fucose can also be directly linked to protein via an O-linkage to Serine or Threonine residues located within consensus sequences contained in Epidermal Growth Factor-like (EGF) repeats and Thrombospondin Type 1 Repeats (TSRs). In this context, fucose is added exclusively to properly folded EGF repeats and TSRs by Protein O-fucosyltransferases 1 and 2, respectively. In both cases, the O-linked fucose can also be elongated with other sugars. Here, we describe the biological importance of these O-fucose glycans and molecular mechanisms by which they affect the function of the proteins they modify. O-Fucosylation of EGF repeats modulates the Notch signaling pathway, while O-fucosylation of TSRs is predicted to influence secretion of targets including several extracellular proteases. Recent data show O-fucose glycans mediate their effects by participating in both intermolecular and intramolecular interactions.
岩藻糖是蛋白质和脂质聚糖上常见的末端修饰物。岩藻糖也可以通过 O 连接与丝氨酸或苏氨酸残基直接连接，这些残基位于表皮生长因子样 (EGF) 重复和血栓反应蛋白 1 型重复 (TSR) 中的共有序列中。在这种情况下，岩藻糖分别由蛋白 O-岩藻糖基转移酶 1 和 2 添加到正确折叠的 EGF 重复和 TSR 中。在这两种情况下，O 连接的岩藻糖也可以用其他糖延长。在这里，我们描述了这些 O-岩藻糖聚糖的生物学重要性以及它们影响所修饰蛋白质功能的分子机制。EGF 重复的 O-岩藻糖基化调节 Notch 信号通路，而 TSR 的 O-岩藻糖基化预计会影响包括几种细胞外蛋白酶在内的靶标的分泌。最近的数据表明，O-岩藻糖聚糖通过参与分子间和分子内相互作用来发挥其作用。
