5flz
From Proteopedia
Cryo-EM structure of gamma-TuSC oligomers in a closed conformation
Structural highlights
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Function[SPC97_YEAST] Involved in microtubule organization by the microtubule organizing center, the spindle pole body (SPB). Probably part of the microtubule attachment site at the SPB. [TBG_YEAST] Tubulin is the major constituent of microtubules. The gamma chain is found at microtubule organizing centers (MTOC) such as the spindle poles or the centrosome, suggesting that it is involved in the minus-end nucleation of microtubule assembly. TUB4 is an important spindle pole body component that organizes both cytoplasmic and nuclear microtubule arrays. [SPC98_YEAST] Involved in microtubule organization by the microtubule organizing center, the spindle pole body (SPB). Probably part of the microtubule attachment site at the SPB. Publication Abstract from PubMedThe gamma-tubulin ring complex (gammaTuRC) is the primary microtubule nucleator in cells. gammaTuRC is assembled from repeating gamma-tubulin small complex (gammaTuSC) subunits and is thought to function as a template by presenting a gamma-tubulin ring that mimics microtubule geometry. However, a previous yeast gammaTuRC structure showed gammaTuSC in an open conformation that prevents matching to microtubule symmetry. By contrast, we show here that gamma-tubulin complexes are in a closed conformation when attached to microtubules. To confirm the functional importance of the closed gammaTuSC ring, we trapped the closed state and determined its structure, showing that the gamma-tubulin ring precisely matches microtubule symmetry and providing detailed insight into gammaTuRC architecture. Importantly, the closed state is a stronger nucleator, thus suggesting that this conformational switch may allosterically control gammaTuRC activity. Finally, we demonstrate that gammaTuRCs have a strong preference for tubulin from the same species. Ring closure activates yeast gammaTuRC for species-specific microtubule nucleation.,Kollman JM, Greenberg CH, Li S, Moritz M, Zelter A, Fong KK, Fernandez JJ, Sali A, Kilmartin J, Davis TN, Agard DA Nat Struct Mol Biol. 2015 Feb;22(2):132-7. doi: 10.1038/nsmb.2953. Epub 2015 Jan , 19. PMID:25599398[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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