Specific roles of complex-modified glycoproteins in plants

与ER中糖蛋白修饰的众所周知的功能相反，高尔基体中获得的N-聚糖多样性的其他作用仍不清楚。在盐胁迫下，我们分配的根生长表型的复合聚糖1（cgl 1）突变体，这类似于径向膨胀（RSW）表型的拟南芥突变体，有缺陷的ER-居民糖基化或纤维素生物合成在质膜。作为一个环节，我们鉴定了β-D-内切葡聚糖酶Korrigan。在这个新项目中，我们建议研究糖基化缺陷如何损害分泌糖蛋白的功能和/或靶向，因为我们的初步结果表明，在植物中N-聚糖也可以编码靶向信息。我们发现，当管腔域丢失（大多数已发表的研究）或异常N-糖基化时，一些II类膜蛋白的定位不同。通过分子和生物化学手段，我们将研究N-聚糖的数量和/或质量对整合糖蛋白的细胞内运输的重要程度：此外，我们最终试图确定内膜系统中相应的受体。我们自己的Y2 H屏幕与纤维素合成酶A1支持，在压力下，信号eminate从细胞壁重编程核表达。因此，从长远来看，我们的目标是确定参与TGN/内体到细胞核，以及质膜到细胞核通讯的组件。

In contrast to the well known functions of glycoprotein modifications in the ER, additional roles of N-glycan diversity acquired in the Golgi are still unclear. Upon salt stress, we assigned a rootgrowth phenotype to complex glycan 1 (cgl1) mutants, which resembles the radial swelling (rsw) phenotype of Arabidopsis mutants that have defects in ER-resident glycosylation or cellulose biosynthesis at the plasma membrane. As one link we identified the β-D-endoglucanase Korrigan. In this new project we propose to examine how glycosylation defects compromize function and/or targeting of secreted glycoproteins, because our preliminary results indicate that also in plants N-glycans can encode targeting information. We found that when the luminal domain is missing (most published studies) or when aberrantly N-glycosylated, some class-II membrane proteins localize differently. By molecular and biochemical means we will examine to what extend number and/or quality of N-glycans are important for intracellular traffic of integral glycoproteins: Moreover, we ultimately attempt to identify corrsponding receptors in the endomembrane system. Our own Y2H screens with cellulose synthase A1 support that upon stress, signals eminate from the cell wall to reprogram nuclear expression. Thus, in the long run, we aim at identifying components involved in TGN/endosome-to-nucleus, and also plasma membrane-to-nucleus communication.