Dr. Applewhite is a cell biologist who studies the cytoskeleton. As a faculty member at a small liberal arts college, he works to tightly integrate his research and teaching. You can read about his some of his thoughts on being a Black and gay scientist here.

Dr. Applewhite attended the University of Michigan for his undergraduate degree, and the Northwestern University for his Ph.D. He completed his postdoctoral training at the University of North Carolina, Chapel Hill. In 2017, he received large research grants from the National Science Foundation and the National Institutes of Health.

The cytoskeleton is a network of protein that provides shape and structure to cells. Within the cell, it provides “tracks” for intracellular movement. But it is also important for cells to move: as the cytoskeleton reshapes the cell to expand in one direction (i.e., forward) and retract in the opposite direction, the cell “slinkies” forward. In particular, the cytoskeleton can create short projections called lamellipodia that treadmill the cell forward. The protein Cortactin is important in forming and stabilizing lamellipodia.

In a recent paper, Dr. Applewhite and a group of primarily undergraduates discovered a </i>Drosophila</i> (fruit fly) gene that interacts with Cortactin, and they named this gene Nausicaa. To do this, they first used a computer program to compare all Drosophila genes to the two human genes that are known to be important partners of Cortactin. Nausicaa was 30% similar to one and 28% similar to the other, but it was most similar in the region that was thought to interact with Cortactin.

Next, they took Drosophila cells (not whole flies, just cells that can be grown in a dish) and expressed Nausicaa fused to a green fluorescent tag. Using a microscope, they were able to see that their protein was mostly in the lamellipodia, and that this went away if they got rid of Cortactin. They then tagged the Cortactin as well, so they could see where the proteins were relative to each other. They found that Nausicaa was almost always in the same place as Cortactin and that if they altered the part of Nausicaa that they thought interacted with Cortactin, it no longer went to the right place. From this, they concluded that Nausicaa is dependent on Cortactin in order to go to the lamellipodia.

Finally, they looked at what happened when they got rid of Nausicaa. They found that Cortactin spent less time in the lamellipodia, the lamellipodia were long and straight instead of branched and moved more slowly, and their movement was less coordinated. Thus, they concluded that Cortactin is constantly coming in and out of association with the cytoskeleton, and Nausicaa helps to stabilize this interaction and slow down the disassociation to enable cell movement.