Effects of anti-microtubule agents on microtubule organization in cells lacking the kinesin-13 MCAK

Abstract

Dynamic microtubules are necessary for proper mitotic spindle assembly and chromosome segregation during mitosis. Members of the kinesin superfamily of molecular motor proteins are important to spindle function. Of particular interest is the Kinesin-13 family member MCAK, which acts to regulate microtubule dynamics during spindle assembly and to ensure proper attachments of chromosomes to spindle microtubules. The unique ability of MCAK to regulate microtubule dynamics makes it a potential target for development of new drugs that alter spindle function. Here, we knocked down MCAK via RNAi in normal and malignant cell lines and found that the two tested malignant cell lines were acutely sensitive to MCAK knockdown, while the tested normal cells were less sensitive. In addition, we looked at the effect of combining MCAK knockdown and drug treatment with paclitaxel or vinblastine to identify spindle assembly defects. We found that MCAK knockdown increased the morphological defects of the microtubule cytoskeleton in HeLa cells caused by anti-microtubule drugs. Our studies support the idea that MCAK would be a good target for new chemotherapeutic development and may be particularly useful in combination therapies with currently available anti-microtubule agents.

Functional and Spatial Regulation of Mitotic Centromere- Associated Kinesin by Cyclin-Dependent Kinase 1

“…In particular, prometaphase/metaphase cells frequently exhibited typical "hairy" spindles ( Fig. 5B, second row, tubulin staining), comparable to earlier reports (8,11,33). In contrast, readdition of MCAK WT rescued the defect in chromosome positioning as well as abnormalities in the mitotic microtubule cytoskeleton induced by siRNA MCAK2 (Fig.…”

“…Overexpression or depletion of MCAK causes cells to sustain in prometaphase yet affects the mitotic indices only slightly (8,10,11,44). We next investigated the functional significance of T537 phosphorylation in the regulation of mitosis.…”

Functional analysis of phosphorylation of the mitotic centromere-associated kinesin by Aurora B kinase in human tumor cells

“…2B), as previously reported. 29,30 Adding back of MCAK WT could efficiently reverse this prophase/prometaphase arrest (Fig. 2B).…”

Kif2a depletion generates chromosome segregation and pole coalescence defects in animal caps and inhibits gastrulation of theXenopusembryo

“…Both MCAK and Kif2a have been shown to contribute to Taxol resistance, presumably because increasing the depolymerase activity can restore more normal dynamics to Taxol-treated cells (Hedrick et al ., 2008; Rizk et al ., 2009). Therefore depleting kinesin-13 activity may increase the efficacy of taxanes.…”