Louis Hodgson, Ph.D., and Dianne Cox, Ph.D., studied the role of the protein Rac2 in forming protrusions that allow mouse macrophages to migrate. In the upper image, computational analysis “maps” the motion (y axis) of a 50-micron cell-edge section over 10 minutes (x axis). Cyclic edge motion is visible in which protrusions (red areas) alternate with retractions (blue areas). Lower image of the same macrophage shows that protrusive activity correlates with Rac2 activity using fluorescent biosensors that reveal when and where Rac2 is activated in the cell (red = high Rac2 activity, blue = low). The research is described in the March 7, 2016 issue of Journal of Immunology, whose cover image resembles the upper image. Dr. Hodgson is associate professor and Dr. Cox is professor of anatomy & structural biology. (Photo credit: Veronika Miskolci, Ph.D., and Gruss-Lipper Biophotonics Center)