Relative Quantitation of Polymerized Actin in Suspension Cells by Flow Cytometry

The amount of polymerized actin within a cell can vary widely due to natural processes and/or experimentally induced perturbations. We routinely use this protocol to measure relative polymerized actin content between cell populations by staining cells in suspension with fluorescent phalloidin, then measuring total cell fluorescence using flow cytometry. Although developed for human cells, we have easily adapted this method for use with diverse eukaryotic cell types.