FIGURE 4.

Copolymerization of WT and D11Q actin. A, filaments obtained by copolymerization of WT actin labeled with Alexa-Fluor 488 and D11Q actin labeled with Alexa-Fluor 594. The two fluorophores were observed in the green (left) and red fluorescence (right) channels, respectively. Arrowheads indicate puncta of Alexa-Fluor 594-D11Q actin within or along copolymers. Bar, 20 μm. B, fluorescence micrograph of Dictyostelium cells expressing GFP-WT actin, GFP-D11Q actin, and GFP-WT actin fused with thymosin β. Arrows indicate the accumulation of GFP-actin along cell peripheries and thin projections, and arrowheads indicate enrichment around macropinocytic cups. Bar, 20 μm. C, Western blotting analysis of cells expressing GFP-WT actin, GFP-D11Q actin, or GFP-D11Q actin fused with thymosin β. Triton-soluble (S) and -insoluble (P) fractions were separated by SDS-PAGE and probed with anti-GFP antibodies.