Collaboration with Richard Kik (Ph.D. student at the Lab. of Physics and Colloid Chemistry)
When a plant cell divides into two new ones, a new cell wall has to be formed to separate the two daughter cells. This starts with the formation of a cell plate (Figure 1). Golgi vesicles fuse into a net-like structure and then into a more or less rigid plate consisting of vesicle derived membrane at the outside, and vesicle content, primary cell wall material, at the inside (Figure 2). The phragmoplast cytoskeleton, consisting of microtubules and actin filaments, plays a crucial role in the transport of vesicles and probably also in their fusion into the cell plate. We study which properties the vesicles need to have in order to be transported to, and fuse together into the cell plate. We microinject fluorescently labeled synthetic ‘vesicles’ of which we can change parameters like size, number, content, composition, coating etc., into dividing Tradescantia virginiana stamen hair cells. At the laboratory of Plant Cell Biology, the vesicle transport over the cytoskeleton and the fusion of vesicles with each other is being studied in living cells. At the same time, in the laboratory of Physics and Colloid Chemistry, PhD student Richard Kik is creating a simplified in vitro system of polymer brushes that mimics the phragmoplast situation in cells. Both in vivo and in vitro, parameters like lipid composition, vesicle coating and vesicle crowding are being studied.