RA-VII, a cyclic depsipeptide, changes the conformational structure of actin to cause G2 arrest by the inhibition of cytokinesis

In L 12 10 cells, RA-VII (0.1-100 nM) caused the concentration-dependent inhibition of the proliferation and G(2) arrest. Treatment of PCl2 cells with 10 nM RA-VII changed cell shape round with binucleation, suggesting the inhibition of cytokinesis. The fluorescence intensity of FITC-phalloidin bound to F-actin was enhanced by RA-VII. In surface plasmon resonance experiments, the signal of F-actin was modified by RA-VII in close agreement with a concentration of FITC-phalloidin binding to F-actin. These results suggest that RA-VII causes the conformational change of F-actin and the stabilization of actin filaments to induce G(2) arrest. (C) 2004 Elsevier Ltd. All rights reserved.