Transfection with moesin-T558D inhibits polarization of PBT cells. PBT cells were “nucleofected” without any DNA (“mock,” ▴), or with moesin constructs that mimic the unphosphorylated form (moesin-T558A-HA; ▪), or the phosphorylated form (moesin-T558D-HA, •). Cells were fixed before stimulation or at varying intervals after stimulation with SDF-1α, permeabilized, and stained for HA plus actin and visualized by fluorescence microscopy. Determination of percentage polarization was performed single blind for polarized cells (percentage of all cells in “mock” and percentage of transfected cells in moesin-transfected populations).