Abstract
The γ-tubulin ring complex (γTuRC) is the major microtubule nucleator in cells. The mechanism of its regulation is not understood. We purified human γTuRC and measured its nucleation properties in a TIRF microscopy-based real-time nucleation assay. We find that single γTuRC complexes nucleate microtubules is a cooperative and stochastic manner. They stably cap microtubule minus ends. Nucleation is inefficient compared to microtubule elongation. A 4 Å resolution cryo-EM structure of γTuRC, combined with crosslinking-mass spectrometry analysis, reveals an asymmetric conformation with only part of the complex in a ‘closed’ conformation matching the microtubule geometry. The opposite side of γTuRC is in an ‘open’, nucleation-incompetent conformation, leading to a structural asymmetry explaining the low nucleation efficiency of human γTuRC. Our data suggest possible regulatory mechanisms for microtubule nucleation by γTuRC closure. [published in Dev. Cell 53, 603-617, 2020; https://doi.org/10.1016/j.devcel.2020.04.019].
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
