Optical Control of G-Actin with a Photoswitchable Latrunculin

Actin is one of the most abundant proteins in eukaryotic cells and a key component of the cytoskeleton. A range of small molecules have emerged that interfere with actin dynamics by either binding to polymeric F-actin or monomeric G-actin to stabilize or destabilize filaments or prevent their formation and growth, respectively. Amongst these, the latrunculins, which bind to G-actin and affect polymerization, are widely used as tools to investigate actin-dependent cellular processes. Here, we report a photoswitchable version of latrunculin, termed opto-latrunculin (OptoLat), which binds to G-actin in a light-dependent fashion and affords optical control over actin polymerization.OptoLatcan be activated with 390 – 490 nm pulsed light and rapidly relaxes to the inactive form in the dark. Light activatedOptoLatinduced depolymerization of F-actin networks in oligodendrocytes and budding yeast, as shown by fluorescence microscopy. Subcellular control of actin dynamics in human cancer cell lines was demonstrated by live cell imaging. Light-activatedOptoLatalso reduced microglia surveillance in organotypic mouse brain slices while ramification was not affected. Incubation in the dark did not alter the structural and functional integrity of microglia. Together, our data demonstrate thatOptoLatis a useful tool for the elucidation of G-actin dependent dynamic processes in cells and tissues.