Microtubule cell cycle-dependent

Belmont LD, Hyman AA, Sawin KE, Mitchison TJ (1990) Real-time visualization of cell cycle-dependent changes in microtubule dynamics in cytoplasmic extracts. Cell 62 579-589... 

Tubulin conjugates are used for observation of cell cycle-dependent microtubule dynamics, mitotic spindle morphogenesis and visualisation of tubulin transport in neurons. 

Roghi C, Giet R, Uzbekov R, Morin N, Chartrain I, Le Guellec R, Couturier A, Doree M, Philippe M, Prigent C. 1998. The Xenopus protein kinase pEg2 associates with the centrosome in a cell cycle-dependent manner, binds to the spindle microtubules and is involved in bipolar mitotic spandle assembly. J Cell Sci 111 ( Pt 5) 557-572... 

The taxanes, paclitaxel and docetaxel, act by promoting the assembly of microtubules. The taxanes induce cell cycle arrest in the most radiosensitive phase, G2/M thereby promoting radiosensitivity. In vitro studies have also demonstrated apoptosis in cell culture lines with paclitaxel (32). Paclitaxel dose-dependent synergy is also seen in squamous carcinoma cell lines (33). Much literature has been published reg arding the use of taxanes when combined with radiotherapy. 

Cyclic uptake and release of Ca2+ from the extracellular medium occur during mitosis in Physarum pofycephalum, and correlate with specific structural and kinetic events in the mitotic nuclei.442 The membrane system in the mitotic apparatus in Haemantkus endosperm cells functions in the localized release of Ca2+, so regulating the events of mitosis.443 It is known that calcium exerts effects on the stability of spindle microtubules. An alternative view is that free magnesium concentration acts as the fundamental regulator of the cell cycle.444 Tubulin polymerization depends on the presence of magnesium and the absence of calcium, and control of the Ca2+/Mg2+ ratio is relevant to spindle assembly. 

Finally, 80 proteins localized to an abnormal intranuclear microtubule structure upon LMB treatment, while others simply occupied nucleus or nucleolus. Crml-dependent dynamic interchange of proteins between the nucleus and the microtubules may regulate microtubule organization during the cell cycle in fission yeast. Further analysis of individual proteins will reveal the involvement of Crml in the process for microtubule assembly and disassembly. 

Interest in paclitaxel was stimulated by the finding that the drug possessed the unique ability to promote microtubule formation at cold temperatures and in the absence of guanosine triphosphate (GTP). It binds specifically to the P-tubulin subunit of microtubules and antagonizes the disassembly of this key cytoskeletal protein, with the result that bundles of microtubules and aberrant structures derived from microtubules appear in the mitotic phase of the cell cycle. Arrest in mitosis follows. Cell killing (CK) is dependent on both drug concentration and duration of cell exposure. 

Chaimovitsh et al. [149] reported on the effect of citral on mitotic microtubules in models of tobacco BY2 cells and wheat roots. Citral disrupted mitotic microtubules and suppressed the cell cycle and also increased the occurrence of asymmetric cell plates in those cells. The effect seemed to be dose-dependent. The authors propose that at lower concentrations, citral influences cell division by disruption of the mitotic microtubules and cell plates at higher concentrations it suppresses the cell elongation by disrupting cortical microtubules. 

Treatment of human cancer cells with low nanomolar concentrations of Epo B produces aberrant mitotic spindles, results in cell cycle arrest in mitosis, and eventually leads to apoptotic cell death. ICjoS for cancer cell growth inhibition are in the nanomolar or even sub-nanomolar range, depending on the specific cell type, In addition, apoptosis induction by Epo B has been suggested to involve the formation of reactive ojygen species in mitochondria it has also been linked to the activation of the nuclear translocation of the transcription factor NFkB in a process that would be independent of the microtubule effects of the compound. The true significance of these findings for the antitumor activity of Epo B still needs to be established. 

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