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 challenging to detect with fluorescence microscopy, making it difficult to determine whether actin filaments are directly associated with specific membranes. To address these limitations, we developed fluorescent-protein-tagged actin nanobodies, termed ‘actin chromobodies’ (ACs), targeted to organelle membranes to enable high-resolution imaging of sub-organellar actin dynamics. Genetically encoded fluorescent-protein-tagged actin nanobodies fused to organelle membrane-targeting sequences enables high-resolution imaging of transient organelle–actin contact sites in live cells.