Actin chromobody imaging reveals sub-organellar actin dynamics

The actin cytoskeleton plays multiple critical roles in cells, from cell migration to organelle dynamics. The small and transient actin structures regulating organelle dynamics are difficult to detect with fluorescence microscopy. We developed an approach using fluorescent protein-tagged actin nanobodies targeted to organelle membranes to enable live cell imaging of sub-organellar actin dynamics with unprecedented spatiotemporal resolution. These probes reveal that ER-associated actin drives fission of multiple organelles including mitochondria, endosomes, lysosomes, peroxisomes, and the Golgi. <fig id="ufig1" position="float" fig-type="figure" orientation="portrait"> <graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="639278v2_ufig1" position="float" orientation="portrait"/> </fig>