Fig. 8. Dispersion of Citron-K-containing patches by disruption of F-actin. (A and B) Effects of latrunculin A (A) or Y-27632 (B) treatment on band-like structures in interphase cells. HeLa cells co-expressing GFP-Citron-K (green) and Myc-Val14RhoA were subjected to each treatment. F-actin is stained in red. (A) Latrunculin A treatment disintegrated the band-like structures of Citron-K and dispersed Citron-K-containing patches throughout the cell cortex. (B) The Y-27632 treatment disrupted stress fibers and dispersed Citron-K containing patches (the left cell). In cells retaining stress fibers, some of the Citron-containing band-like structures remained (the right-hand cell). (C) Effects of F-actin disruption on Citron-K accumulation in mitotic cells. HeLa cells expressing GFP-Citron-K were enriched in M-phase, subjected to latrunculin A treatment, and stained for endogenous RhoA (red) and for DNA (blue). In the dividing cells treated with latrunculin A, GFP-Citron-K (green) was not seen as a ring-like structure in the cleavage furrow but dispersed as patches all around the cell cortex. In the dispersed patches, colocalization with endogenous RhoA is also observed. Endogenous RhoA also remains in the putative cleavage furrow (arrowheads). Confocal sections of three different cells are shown. The same pattern was also observed with cytochalasin D treatment. Bars, 10 µm.