This kit is designed to monitor actin dynamics in live cells. The kit includes lentiviral vectors encoding actin fusions to DD-AcGFP1 (green, destabilized) and mCherry (red), and the DD's stabilizing ligand Shield1. DD-AcGFP1-Actin is continuously targeted for degradation in the cell by the proteasomes, unless the cells are cultured in medium containing the stabilizing ligand Shield1. By contrast, mCherry-Actin (which does not contain the DD) has normal stability upon expression, and is constitutively present in the cell. Adding and removing Shield1 creates a “pulse-chase” like set of conditions which allow you to monitor polymerization of actin monomers as newly synthesized DD-AcGFP1-Actin that is stabilized by Shield1 (green) is integrated into the existing (red) mCherry-Actin actin filament network.