The Fritz-Laylin lab will explore how cells can repurpose the same protein network to perform very different tasks. Cells rely on complex networks built from the protein actin for numerous activities, including some that operate in opposition at the same time. For example, actin networks that push out the edge of the cell membrane allow cells to crawl across a surface, while those that push in small patches of the membrane allow cells to ingest nutrients, a process called endocytosis. How actin networks can execute such opposing actions without becoming jumbled is a mystery. I previously discovered a fungus that appears to temporally separate the way its actin networks are deployed; our data indicate that it uses actin exclusively for crawling during its initial infectious phase, but later uses actin to drive the endocytosis needed to support its rapid growth. Now, combining cutting-edge methods in biochemistry, microscopy, and comparative genomics, our group will determine how the components of these functionally distinct networks differ and identify the molecular signal that, during fungal development, triggers the transition from one to the other. This work could lead to methods for eradicating this environmental pathogen or for disrupting the actin networks that foster cancer progression.