8vt7 | pdb_00008vt7
Structure of the gamma tubulin ring complex nucleated microtubule protofilament.
Structural highlights
DiseaseTBB3_HUMAN Congenital fibrosis of extraocular muscles;Cortical dysgenesis with pontocerebellar hypoplasia due to TUBB3 mutation. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. FunctionTBB3_HUMAN 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. TUBB3 plays a critical role in proper axon guidance and mantainance.[1] Publication Abstract from PubMedMicrotubules are composed of alpha-tubulin and beta-tubulin dimers positioned head-to-tail to form protofilaments that associate laterally in varying numbers. It is not known how cellular microtubules assemble with the canonical 13-protofilament architecture, resulting in micrometer-scale alpha/beta-tubulin tracks for intracellular transport that align with, rather than spiral along, the long axis of the filament. We report that the human ~2.3 MDa gamma-tubulin ring complex (gamma-TuRC), an essential regulator of microtubule formation that contains 14 gamma-tubulins, selectively nucleates 13-protofilament microtubules. Cryogenic electron microscopy reconstructions of gamma-TuRC-capped microtubule minus ends reveal the extensive intra-domain and inter-domain motions of gamma-TuRC subunits that accommodate luminal bridge components and establish lateral and longitudinal interactions between gamma-tubulins and alpha-tubulins. Our structures suggest that gamma-TuRC, an inefficient nucleation template owing to its splayed conformation, can transform into a compacted cap at the microtubule minus end and set the lattice architecture of cellular microtubules. , PMID:38609661[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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