Figure 7. Shortened mitotic spindles in Pten-deficient cells can be rescued by both protein phosphatase-proficient PTEN and phospho-dead EG5.

(a) Ectopic expression of wild type and phosphatase-deficient PTEN in Pten null cells. Akt phosphorylation was also shown to verify the lack of lipid phosphatase activity of PTEN mutants C124S and G129E. (b,c) The spindle length and pole integrity were analysed in Pten^−/− cells transfected with PTEN, PTEN^C124S or PTEN^G129E as indicated in a. Data are presented as means±s.e.m. and analysed by one-way analysis of variance (ANOVA) followed by Dunnett's multiple comparison tests. (d) Pten^−/− cells were transfected with EG5^T926A, a phospho-dead mutant of EG5, or an empty vector (Control). Cells were subjected to immunofluorescent analysis of metaphase spindle pole distances. Pten^+/+ cells were also included as a control. Data are presented as means±s.e.m. and analysed by one-way ANOVA followed by Turkey's multiple comparisons. (e) Pten^−/− cells with and without EG5^T926A were analysed for mitotic spindle pole fragmentation. Data were analysed by unpaired two-tailed t test. *P<0.05; **P<0.01; ***P<0.001.