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Article Dans Une Revue Journal of Biological Chemistry Année : 2010

GDP-Tubulin Incorporation into Growing Microtubules Modulates Polymer Stability.

Résumé

Microtubule growth proceeds through the endwise addition of nucleotide-bound tubulin dimers. The microtubule wall is composed of GDP-tubulin subunits, which are thought to come exclusively from the incorporation of GTP-tubulin complexes at microtubule ends followed by GTP hydrolysis within the polymer. The possibility of a direct GDP-tubulin incorporation into growing polymers is regarded as hardly compatible with recent structural data. Here, we have examined GTP-tubulin and GDP-tubulin incorporation into polymerizing microtubules using a minimal assembly system comprised of nucleotide-bound tubulin dimers, in the absence of free nucleotide. We find that GDP-tubulin complexes can efficiently co-polymerize with GTP-tubulin complexes during microtubule assembly. GDP-tubulin incorporation into microtubules occurs with similar efficiency during bulk microtubule assembly as during microtubule growth from seeds or centrosomes. Microtubules formed from GTP-tubulin/GDP-tubulin mixtures display altered microtubule dynamics, in particular a decreased shrinkage rate, apparently due to intrinsic modifications of the polymer disassembly properties. Thus, although microtubules polymerized from GTP-tubulin/GDP-tubulin mixtures or from homogeneous GTP-tubulin solutions are both composed of GDP-tubulin subunits, they have different dynamic properties, and this may reveal a novel form of microtubule "structural plasticity."
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Dates et versions

hal-00488194 , version 1 (13-07-2010)

Identifiants

Citer

Odile Valiron, Isabelle Arnal, Nicolas Caudron, Didier Job. GDP-Tubulin Incorporation into Growing Microtubules Modulates Polymer Stability.. Journal of Biological Chemistry, 2010, 285 (23), pp.17507-13. ⟨10.1074/jbc.M109.099515⟩. ⟨hal-00488194⟩
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