Fundamental cellular processes such as migration and division rely on the precise spatial and temporal coordination of dynamic changes in cell shape. These shape changes are driven by continuous rearrangements of the actin cytoskeleton. Disruption of the molecular mechanisms governing these rearrangements can lead to pathological consequences, including uncontrolled proliferation, tumor cell invasion, and metastasis.

The Rho family of GTPases—most notably Rho, Cdc42, and Rac—are central regulators of actin dynamics and cell morphology. Mutations in these GTPases or their upstream activators, such as guanine nucleotide exchange factors (GEFs), are frequently linked to cancer-related phenotypes. Our research aims to elucidate how specific spatial and temporal activity patterns of Rho GTPases are generated, and how these signals are translated into both normal and aberrant cellular behaviors.

Rho GTPase activity is tightly regulated by multiple classes of proteins acting in concert. GEFs promote activation by facilitating GTP loading, while GTPase-activating proteins (GAPs) enhance GTP hydrolysis, leading to inactivation. Guanine nucleotide dissociation inhibitors (GDIs) maintain Rho GTPases in a soluble cytosolic state, preventing their activation at the membrane.

To dissect the components and dynamics of Rho GTPase signaling networks, we employ a broad array of cell biological and advanced microscopy techniques. In particular, we use high-resolution imaging modalities such as TIRF, spinning disk, and structured illumination microscopy (SIM) to visualize molecular processes in living cells. These methods are complemented by fluorescence-based activity sensors and rapid, chemically- and optogenetically-driven protein perturbation strategies. Together, these approaches enable us to directly investigate causal relationships between key signaling components and their roles in organizing molecular processes in space and time to control cell behavior.