9eok

Minus end of the vertebrate gamma-tubulin ring complex-capped microtubule

spinqualitylabelsall models 9eok, resolution 23.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9eok is a 42 chain structure with sequence from Xenopus laevis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 23Å Ligands: GDP, GTP, MG, TA1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q5U4V6_XENLA 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.[RuleBase:RU000352] Publication Abstract from PubMed The gamma-tubulin ring complex (gamma-TuRC) is a structural template for de novo microtubule assembly from alpha/beta-tubulin units. The isolated vertebrate gamma-TuRC assumes an asymmetric, open structure deviating from microtubule geometry, suggesting that gamma-TuRC closure may underlie regulation of microtubule nucleation. Here, we isolate native gamma-TuRC-capped microtubules from Xenopus laevis egg extract nucleated through the RanGTP-induced pathway for spindle assembly and determine their cryo-EM structure. Intriguingly, the microtubule minus end-bound gamma-TuRC is only partially closed and consequently, the emanating microtubule is locally misaligned with the gamma-TuRC and asymmetric. In the partially closed conformation of the gamma-TuRC, the actin-containing lumenal bridge is locally destabilised, suggesting lumenal bridge modulation in microtubule nucleation. The microtubule-binding protein CAMSAP2 specifically binds the minus end of gamma-TuRC-capped microtubules, indicating that the asymmetric minus end structure may underlie recruitment of microtubule-modulating factors for gamma-TuRC release. Collectively, we reveal a surprisingly asymmetric microtubule minus end protofilament organisation diverging from the regular microtubule structure, with direct implications for the kinetics and regulation of nucleation and subsequent modulation of microtubules during spindle assembly. gamma-TuRC asymmetry induces local protofilament mismatch at the RanGTP-stimulated microtubule minus end.,Vermeulen BJ, Bohler A, Gao Q, Neuner A, Zupa E, Chu Z, Wurtz M, Jakle U, Gruss OJ, Pfeffer S, Schiebel E EMBO J. 2024 May;43(10):2062-2085. doi: 10.1038/s44318-024-00087-4. Epub 2024 Apr , 10. PMID:38600243 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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