8vrk
Rigid body fitted model for refined density map of gamma tubulin ring complex capped microtubuleRigid body fitted model for refined density map of gamma tubulin ring complex capped microtubule
Structural highlights
FunctionTBA1B_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. 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. Structure of the gamma-tubulin ring complex-capped microtubule.,Aher A, Urnavicius L, Xue A, Neselu K, Kapoor TM Nat Struct Mol Biol. 2024 Jul;31(7):1124-1133. doi: 10.1038/s41594-024-01264-z. , Epub 2024 Apr 12. PMID:38609661[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
|
| ||||||||||||||||