fantastic vesicle traffic

     Author: Daniel von Wangenheim

The miracle of life relies in its cells.

The root hair is one of the fastest growing cells in the plant. To allow this rapid growth, continuous delivery of membrane and cell wall material to the growing tip of the hair cell is required. A component part of this material is protein, which is synthesized by ribosomes along the Endoplasmic Reticulum, modified in the Golgi apparatus and packaged into vesicles. The vesicles are finally delivered to the plasma membrane by motor proteins along the cytoskeleton. How do vesicles find their target membranes? The specificity of target recognition is mediated by the interaction of v-SNARE proteins on the vesicle surface with t-SNARE proteins on the target membrane. Among others, small G-proteins regulate this process. One group of small G-proteins is the so-called RabGTPases.

To visualize the distribution of such a RabGTPase proteins within the cells, they are tagged with the Green Fluorescent Protein. The video shows the germination of Arabidopsis thaliana seeds, zooming in on the root hairs, which display movement of fluorescent vesicles through the cytoplasm, and finally one can see an animation of myosin VI motor proteins dragging the fluoresently marked vesicles along actin filaments.