Klaus M. Hahn

The paper introduces GTPase biosensors that report activity without blocking ligand interactions, revealing feedback mechanisms in Rac1 regulation.

The paper develops a membrane-permeable small molecule biosensor, CaMero, to detect calmodulin activation in cells and animals without genetic modification.

This study uses optogenetics and biosensor imaging to show RhoG activates Rac1 and Cdc42 in cell protrusion, with RhoG's effects on protrusion partially mediated by Rac1 and some independent of it.

The paper uses reaction-diffusion models to explain rosette pattern formation during frustrated phagocytosis, identifying two mechanisms involving intermediate species and spatial gradients.

The paper develops optogenetic tools to control Rac1 and Rap1 activity in living cells, showing increased membrane localization and effects on cell morphology.