Fluorescence-based actin turnover dynamics of stem cells as a profiling method for stem cell functional evolution, heterogeneity and phenotypic lineage parsing

SiR-actin (SA), a cell-permeable fluorogenic probe (white stars), markedly increases its intensity only when bound (red stars) to actin filaments (F-actin). Following a wash after prolonged staining, F-actin turnover results in net detachment of the probe due to disassembly and/or reorganization of dynamic actin filaments. Temporal declining intensity of the probe can be harnessed for analysis of actin turnover dynamics of single cells in diverse ways, as shown in the figure.