Our hosting provider will be performing UPS maintenance on Tuesday, Oct 25, 2016 between 8 AM and 5 PM PDT. SciCrunch searching services will be down during this time.

Preparing your results

Our searching services are busy right now. Your search will reload in five seconds.

Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

The structure of the gamma-tubulin small complex: implications of its architecture and flexibility for microtubule nucleation.


The gamma-tubulin small complex (gamma-TuSC) is an evolutionarily conserved heterotetramer essential for microtubule nucleation. We have determined the structure of the Saccharomyces cerevisiae gamma-TuSC at 25-A resolution by electron microscopy. gamma-TuSC is Y-shaped, with an elongated body connected to two arms. Gold labeling showed that the two gamma-tubulins are located in lobes at the ends of the arms, and the relative orientations of the other gamma-TuSC components were determined by in vivo FRET. The structures of different subpopulations of gamma-TuSC indicate flexibility in the connection between a mobile arm and the rest of the complex, resulting in variation of the relative positions and orientations of the gamma-tubulins. In all of the structures, the gamma-tubulins are distinctly separated, a configuration incompatible with the microtubule lattice. The separation of the gamma-tubulins in isolated gamma-TuSC likely plays a role in suppressing its intrinsic microtubule-nucleating activity, which is relatively weak until the gamma-TuSC is incorporated into higher order complexes or localized to microtubule-organizing centers. We propose that further movement of the mobile arm is required to bring the gamma-tubulins together in microtubule-like interactions, and provide a template for microtubule growth.

Pubmed ID: 17978090


  • Kollman JM
  • Zelter A
  • Muller EG
  • Fox B
  • Rice LM
  • Davis TN
  • Agard DA


Molecular biology of the cell

Publication Data

January 3, 2008

Associated Grants

  • Agency: NIGMS NIH HHS, Id: F32 GM-078790
  • Agency: NCRR NIH HHS, Id: P41 RR-011823
  • Agency: NCRR NIH HHS, Id: P41 RR011823
  • Agency: NIGMS NIH HHS, Id: R01 GM-040506
  • Agency: NIGMS NIH HHS, Id: R01 GM-31627
  • Agency: Howard Hughes Medical Institute, Id:

Mesh Terms

  • Fluorescence Resonance Energy Transfer
  • Microscopy, Electron
  • Microtubules
  • Models, Molecular
  • Nucleotides
  • Pliability
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Tubulin