Valency and Geometry of multivalent Glycolipid binding as cellular targeting mechnaism in viral infection

糖脂结合病毒如DNA肿瘤病毒SV40使用网格蛋白非依赖性摄取途径进入细胞进行生产性感染。为此，他们利用SV40与糖脂GM1的多价结合来进行膜变形，从而导致内吞作用。然而，这一途径背后的物理化学机制仍然知之甚少，目前还不清楚，是否所有糖脂结合多瘤病毒科遵循类似的路线。与此同时，目前尚不清楚为什么球形GM1结合的SV40病毒粒子被运输到内质网（ER），导致生产性感染，而同样的GM1聚集霍乱毒素β亚基（CTxB）最终在高尔基体和未聚集的GM1分子再循环到质膜。我们的目标是找出，无论是病毒配体的球状几何排列的碳水化合物结合位点是一个一般的机制，在病毒感染的膜变形，以及如何的数量，性质和安排的碳水化合物结合位点控制细胞的摄取和病毒体的感染。为此，我们将结合联合收割机的一些活细胞，在原位和体外高分辨率和X射线显微镜测定。

Glycolipid-binding viruses such as the DNA tumorvirus SV40 use clathrin-independent uptake pathways to enter cells for productive infection. To do so, they exploit the multivalent binding of SV40 to the glycolipid GM1 for membrane deformation leading to endocytosis. However, the physicochemical mechanism behind this pathway remains poorly understood and it is unclear, whether all glycolipid-binding polyomaviridae follow a similar route. At the same time, it remains unclear, why the globular GM1-binding SV40 virion is trafficked to the endoplasmatic reticulum (ER) leading to productive infection, while the likewise GM1-clustering Cholera toxin beta subunit (CTxB) ends up in the Golgi apparatus and unclustered GM1 molecules recycle to the plasma membrane. We aim here to find out, whether the globular geometric arrangement of viral ligands to carbohydrate binding sites is a general mechanism for membrane deformation in viral infection and how the number, nature and arrangement of carbohydrate binding sites controls cellular uptake and infection of virions. To do so, we will combine a number of live-cell, in situ and in vitro assays with high resolution and X-ray microscopy.