Polyamine sharing between tubulin dimers favours microtubule nucleation and elongation via facilitated diffusion - Inserm - Institut national de la santé et de la recherche médicale Accéder directement au contenu
Article Dans Une Revue PLoS Computational Biology Année : 2009

Polyamine sharing between tubulin dimers favours microtubule nucleation and elongation via facilitated diffusion

Résumé

We suggest for the first time that the action of multivalent cations on microtubule dynamics can result from facilitated diffusion of GTP-tubulin to the microtubule ends. Facilitated diffusion can promote microtubule assembly, because, upon encountering a growing nucleus or the microtubule wall, random GTP-tubulin sliding on their surfaces will increase the probability of association to the target sites (nucleation sites or MT ends). This is an original explanation for understanding the apparent discrepancy between the high rate of microtubule elongation and the low rate of tubulin association at the microtubule ends in the viscous cytoplasm. The mechanism of facilitated diffusion requires an attraction force between two tubulins, which can result from the sharing of multivalent counterions. Natural polyamines (putrescine, spermidine, and spermine) are present in all living cells and are potent agents to trigger tubulin self-attraction. By using an analytical model, we analyze the implication of facilitated diffusion mediated by polyamines on nucleation and elongation of microtubules. In vitro experiments using pure tubulin indicate that the promotion of microtubule assembly by polyamines is typical of facilitated diffusion. The results presented here show that polyamines can be of particular importance for the regulation of the microtubule network in vivo and provide the basis for further investigations into the effects of facilitated diffusion on cytoskeleton dynamics.
Fichier principal
Vignette du fichier
journal.pcbi.1000255.pdf (964.31 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

inserm-00705780 , version 1 (08-06-2012)

Identifiants

Citer

Alain Mechulam, Konstantin G. Chernov, Elodie Mucher, Loic Hamon, Patrick A. Curmi, et al.. Polyamine sharing between tubulin dimers favours microtubule nucleation and elongation via facilitated diffusion. PLoS Computational Biology, 2009, 5 (1), pp.e1000255. ⟨10.1371/journal.pcbi.1000255⟩. ⟨inserm-00705780⟩
249 Consultations
340 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More