Model Membranes
To gain insight into the physico-chemical basis for protein and lipid sorting within the Golgi apparatus, we plan to reconstitute GFP-tagged Golgi proteins in giant unilamellar vesicles (GUVs) comprised of different lipids and to study the proteins’ phase separation properties in this system. Because fluorescently-labeled proteins in GUVs can be visualized on a confocal microscope, it will be relatively straightforward to determine their phase properties, for example, whether they show preferential localization to either the liquid-ordered or the liquid-disordered phase of a GUV. We can then study the different contributions of lipid composition and membrane curvature to sorting events in this system. For example, the curvature and tension in the GUV membrane increases by pulling membrane tubules out from it. Any increase or decrease of Golgi protein content in the tubule compared to the bulk membrane during this manipulation will give a direct measure for the contribution of curvature to the sorting event. We will also investigate whether the lipid environment influences the formation of protein oligomers, given that oligomerization has been shown to be a prerequisite for ER export and a property of Golgi resident proteins.
For more information, contact Christian Wunder or Suliana Manley.
