Figure 2. Cdc42 and trafficking pathways in fission yeast. Proteins can be secreted or targeted to the cell surface in secretory vesicles (SV) that are directed via actin cables and are tethered by the exocyst protein complex to specific sites of the plasma membrane. Molecules taken up from the plasma membrane are delivered to early endosomes by an endocytic process that might lead to a route of recycling or to complete degradation in the vacuole. Cdc42 regulates the actin-directed vesicle delivery to the plasma membrane, the exocyst function, and the endosome to vacuole fusion.