Fig. 6

PLK1 depletion antagonizes PIP4KIIγ depletion-induced MT instability. a, b Down-regulation of PLK1 ameliorates PIP4KIIγ depletion-induced instability of spindle pole-associated MT. Representative images of the mitotic spindle after monastrol and cold treatment (a). The control (pLKO) or PIP4KIIγ-depleted (sh2C) CGL2 cells were first transduced with virion containing PLK1-specific shRNA at the indicated MOI. Forty-eight hours after transduction, the cells were seeded onto coverslips for another 20 h before monastrol and cold treatment as described in Fig. 3e. The percentages of mitotic cells with disorganized and shorter spindle pole-associated cold-resistant K-MT (b). Results are the mean ± SD of at least 250 mitotic cells from three independent experiments. **p < 0.01 by Student’s t test. c Down-regulation of PLK1 represses the PIP4KIIγ depletion-induced cell resistance to arsenic trioxide (ATO). The control (pLKO) or PIP4KIIγ-depleted (sh2C) CGL2 cells were first transduced with virion containing PLK1-specific shRNA at the indicated MOI. Forty-eight hours after transduction, the cells were seeded for another 20 h before being treated with 0 or 1 μM ATO for 72 h. Cell viability was then determined. Results are the mean ± SD from three independent experiments. **p < 0.01 by Student’s t test