Figure 1.

PMA treatment induces β-actin translocation to the nucleus. HL-60 cells (A) and human monocytes (B) were left untreated or treated with PMA (10 ng/ml) for 24, 48, and 72 h. Total cell, cytoplasmic, and nuclear extracts (TE, CE, and NE, respectively) were prepared as described in Materials and Methods. Total and subcellular β-actin expression was analyzed by Western blot analysis. The expression of the cytoplasmic marker GAPDH and nuclear marker HDAC1 were also monitored. (C) HL-60 cells treated with or without PMA (10 ng/ml) for 48 h were then fixed with 3% paraformaldehyde and permeabilized with 0.18% Triton X-100. Subsequently, the cells were labeled with a monoclonal mouse anti-β-actin antibody, followed by Alexa Four 568 goat anti-mouse IgG (red). The nuclei were stained with DAPI (blue). (D) Transfected HL-60 cells expressing GFP-β-actin fusion protein were left untreated or treated with PMA for 48 h, and then the effects of PMA treatment on GFP-β-actin distribution in the transfected cells was observed with an AxioVision 3.1 microscope (Carl Zeiss).