Seifert Georg J
Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell biology, University of Natural Resources and Life Sciences Vienna, Vienna, Austria.
Front Plant Sci. 2020 Sep 10;11:563735. doi: 10.3389/fpls.2020.563735. eCollection 2020.
In a plant-specific mode of protein glycosylation, various sugars and glycans are attached to hydroxyproline giving rise to a variety of diverse glycoproteins. The sub-family of arabinogalactan proteins is implicated in a multitude of biological functions, however, the mechanistic role of glycosylation on AGPs by type II arabinogalactans is largely elusive. Some models suggest roles of the glycans such as in ligand-receptor interactions and as localized calcium ion store. Structurally different but possibly analogous types of protein glycosylation exist in animal and yeast models and roles for glycans were suggested in determining the fate of glycoproteins by affecting intracellular sorting or proteolytic activation and degradation. At present, only few examples exist that describe how the fate of artificial and endogenous arabinogalactan proteins is affected by glycosylation with type II arabinogalactans. In addition to other roles, these glycans might act as a molecular determinant for cellular localization and protein lifetime of many endogenous proteins.
在植物特有的蛋白质糖基化模式中，各种糖类和聚糖附着于羟脯氨酸上，从而产生多种不同的糖蛋白。阿拉伯半乳聚糖蛋白亚家族涉及多种生物学功能，然而，II型阿拉伯半乳聚糖对阿拉伯半乳聚糖蛋白进行糖基化修饰的机制作用在很大程度上仍不清楚。一些模型表明聚糖具有诸如配体 - 受体相互作用以及作为局部钙离子储存库等作用。在动物和酵母模型中存在结构不同但可能类似的蛋白质糖基化类型，并且有人提出聚糖在通过影响细胞内分选或蛋白水解激活及降解来决定糖蛋白命运方面发挥作用。目前，仅有少数例子描述了II型阿拉伯半乳聚糖糖基化如何影响人工和内源性阿拉伯半乳聚糖蛋白的命运。除了其他作用外，这些聚糖可能作为许多内源性蛋白质细胞定位和蛋白质寿命的分子决定因素。
