1. The microtubule cytoskeleton is required for a G2 cell cycle delay in cancer cells lacking stathmin and p53.
- Author
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Carney BK, Caruso Silva V, and Cassimeris L
- Subjects
- Apoptosis drug effects, Centrosome drug effects, Cytoskeleton drug effects, G2 Phase drug effects, HeLa Cells, Humans, Microtubules drug effects, Mitosis drug effects, Mitosis physiology, Nocodazole pharmacology, Paclitaxel pharmacology, Phosphorylation drug effects, RNA, Small Interfering genetics, Stathmin antagonists & inhibitors, Stathmin genetics, Tubulin metabolism, Tumor Suppressor Protein p53 antagonists & inhibitors, Tumor Suppressor Protein p53 genetics, Vinblastine pharmacology, Cytoskeleton metabolism, G2 Phase physiology, Microtubules metabolism, Stathmin metabolism, Tubulin Modulators pharmacology, Tumor Suppressor Protein p53 metabolism
- Abstract
In several cancer cell lines, depleting the microtubule (MT)-destabilizing protein stathmin/oncoprotein18 leads to a G2 cell cycle delay and apoptosis. These phenotypes are observed only in synergy with low levels of p53, but the pathway(s) activated by stathmin depletion to delay the cell cycle are unknown. We found that stathmin depletion caused greater MT stability in synergy with loss of p53, measured by the levels of acetylated α-tubulin and the rate of centrosomal MT nucleation. Nocodazole or vinblastine-induced MT depolymerization abrogated the stathmin-depletion induced G2 delay, measured by the percentage of cells staining positive for several markers (TPX2, CDK1 with inhibitory phosphorylation), indicating that MTs are required to lengthen G2. Live cell imaging showed that stathmin depletion increased time in G2 without an impact on the duration of mitosis, indicating that the longer interphase duration is not simply a consequence of a previous slowed mitosis. In contrast, stabilization of MTs with paclitaxel (8 nM) slowed mitosis without lengthening the duration of interphase, demonstrating that increased MT stability alone is not sufficient to delay cells in G2., (Copyright © 2012 Wiley Periodicals, Inc.)
- Published
- 2012
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