9G40

Structure of the Position 7 CMG-decorated gamma-Tubulin Ring Complex from Pig Brain

Summary for 9G40

• Entry DOI: 10.2210/pdb9g40/pdb
• EMDB information: 51020
• Descriptor: Gamma-tubulin complex component 3, Gamma-tubulin complex component, Mitotic-spindle organizing protein 2A isoform X4, ... (4 entities in total)
• Functional Keywords: tubulin complex, structural protein
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 5
• Total formula weight: 652390.94

Authors

Munoz-Hernandez, H.,Krutyholowa, R.,Wieczorek, M. (deposition date: 2024-07-12, release date: 2024-10-02, Last modification date: 2024-10-09)

Primary citation

Xu, Y.,Munoz-Hernandez, H.,Krutyholowa, R.,Marxer, F.,Cetin, F.,Wieczorek, M.
Partial closure of the gamma-tubulin ring complex by CDK5RAP2 activates microtubule nucleation.
Dev.Cell, 2024

PubMed Abstract: Microtubule nucleation is templated by the γ-tubulin ring complex (γ-TuRC), but its structure deviates from the geometry of α-/β-tubulin in the microtubule, explaining the complex's poor nucleating activity. Several proteins may activate the γ-TuRC, but the mechanisms underlying activation are not known. Here, we determined the structure of the porcine γ-TuRC purified using CDK5RAP2's centrosomin motif 1 (CM1). We identified an unexpected conformation of the γ-TuRC bound to multiple protein modules containing MZT2, GCP2, and CDK5RAP2, resulting in a long-range constriction of the γ-tubulin ring that brings it in closer agreement with the 13-protofilament microtubule. Additional CDK5RAP2 promoted γ-TuRC decoration and stimulated the microtubule-nucleating activities of the porcine γ-TuRC and a reconstituted, CM1-free human complex in single-molecule assays. Our results provide a structural mechanism for the control of microtubule nucleation by CM1 proteins and identify conformational transitions in the γ-TuRC that prime it for microtubule nucleation.

PubMed: 39321808
DOI: 10.1016/j.devcel.2024.09.002

Experimental method

ELECTRON MICROSCOPY (4.3 Å)