Department of Biology, Duke University, Durham, NC 27708, USA.
Curr Opin Struct Biol. 2021 Jun;68:113-121. doi: 10.1016/j.sbi.2020.12.013. Epub 2021 Jan 18.
In metazoans, protein O-fucosylation of Ser/Thr residues was only found in secreted or cell surface proteins, and this post-translational modification is catalyzed by ER-localized protein O-fucosyltransferases (POFUTs) in the GT65 family. Recently, a novel nucleocytoplasmic POFUT, SPINDLY (SPY), was identified in the reference plant Arabidopsis thaliana to modify nuclear transcription regulators DELLAs, revealing a new regulatory mechanism for gene expression. The paralog of AtSPY, SECRET AGENT (SEC), is an O-link-N-acetylglucosamine (GlcNAc) transferase (OGT), which O-GlcNAcylates Ser/Thr residues of target proteins. Both AtSPY and AtSEC are tetratricopeptide repeat-domain-containing glycosyltransferases in the GT41 family. The discovery that AtSPY is a POFUT clarified decades of miss-classification of AtSPY as an OGT. SPY and SEC play pleiotropic roles in plant development, and the interactions between SPY and SEC are complex. SPY-like genes are conserved in diverse organisms, except in fungi and metazoans, suggesting that O-fucosylation is a common mechanism in modulating intracellular protein functions.
在后生动物中，丝氨酸/苏氨酸残基的蛋白质 O-连接岩藻糖基化仅在分泌蛋白或细胞表面蛋白中发现，这种翻译后修饰是由内质网定位的 GT65 家族中的蛋白质 O-岩藻糖基转移酶 (POFUT) 催化的。最近，在参考植物拟南芥中鉴定出一种新型核质 POFUT，即 SPINDLY（SPY），它修饰核转录调节剂 DELLAs，揭示了基因表达的新调控机制。AtSPY 的同源物 SECRET AGENT（SEC）是一种 O-连接 N-乙酰葡萄糖胺（GlcNAc）转移酶（OGT），它可以 O-糖基化靶蛋白的丝氨酸/苏氨酸残基。AtSPY 和 AtSEC 都是 GT41 家族中含有四肽重复结构域的糖基转移酶。AtSPY 是 POFUT 的发现澄清了 AtSPY 作为 OGT 的数十年分类错误。SPY 和 SEC 在植物发育中发挥多种作用，SPY 和 SEC 之间的相互作用很复杂。SPY 样基因在不同的生物体中是保守的，除了真菌和后生动物，这表明 O-岩藻糖基化是调节细胞内蛋白质功能的一种常见机制。
