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| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [https://www.uniprot.org/uniprot/TBA1_DROME TBA1_DROME] Tubulin is the major constituent of microtubules. It binds two moles of GTP, one at an exchangeable site on the beta chain and one at a non-exchangeable site on the alpha chain. | + | [https://www.uniprot.org/uniprot/TBB1_DROME TBB1_DROME] Tubulin is the major constituent of microtubules, a cylinder consisting of laterally associated linear protofilaments composed of alpha- and beta-tubulin heterodimers. Microtubules grow by the addition of GTP-tubulin dimers to the microtubule end, where a stabilizing cap forms. Below the cap, tubulin dimers are in GDP-bound state, owing to GTPase activity of alpha-tubulin. |
| - | <div style="background-color:#fffaf0;">
| + | |
| - | == Publication Abstract from PubMed ==
| + | |
| - | In eukaryotes, the dynamic assembly of microtubules (MT) plays an important role in numerous cellular processes. The underlying mechanism of GTP triggering MT assembly is still unknown. Here, we present cryo-EM structures of tubulin heterodimer at their GTP- and GDP-bound states, intermediate assembly states of GTP-tubulin, and final assembly stages of MT. Both GTP- and GDP-tubulin heterodimers adopt similar curved conformations with subtle flexibility differences. In head-to-tail oligomers of tubulin heterodimers, the inter-dimer interface of GDP-tubulin exhibits greater flexibility, particularly in tangential bending. Cryo-EM of the intermediate assembly states reveals two types of tubulin lateral contacts, "Tube-bond" and "MT-bond". Further, molecular dynamics (MD) simulations show that GTP triggers lateral contact formation in MT assembly in multiple sequential steps, gradually straightening the curved tubulin heterodimers. Therefore, we propose a flexible model of GTP-initiated MT assembly, including the formation of longitudinal and lateral contacts, to explain the nucleation and assembly of MT.
| + | |
| | | | |
| - | Structural insights into the mechanism of GTP initiation of microtubule assembly.,Zhou J, Wang A, Song Y, Liu N, Wang J, Li Y, Liang X, Li G, Chu H, Wang HW Nat Commun. 2023 Sep 25;14(1):5980. doi: 10.1038/s41467-023-41615-w. PMID:37749104<ref>PMID:37749104</ref>
| + | ==See Also== |
| - | | + | *[[Tubulin 3D Structures|Tubulin 3D Structures]] |
| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
| + | |
| - | </div>
| + | |
| - | <div class="pdbe-citations 7ysr" style="background-color:#fffaf0;"></div>
| + | |
| - | == References == | + | |
| - | <references/>
| + | |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
