The key to establishing polarity is to sort certain proteins to specific sites within the cell. For instance, the apical surface of an epithelial cell contains a different set of proteins than those found at the basolateral surface. Similarly, the proteins found within the axon of a neuron are often different from those founds at the tips of dendrites. The cell accomplishes this task of protein sorting using several mechanisms. One prominent mechanism is the intracellular transport of cargo using molecular motors. Another mechanism used by cells to establish polarity is the endocytic pathway. Both of these topics are areas of active research in our lab. The two primary models that we use for these studies are mammalian cell lines and Drosophila melanogaster (fruit flies) .