Microtubules are one of the three major cytoskeletal structures in eukaryotic cells. γ-Tubulin ring complexes (γ-TuRCs) play key roles in microtubule organization by mediating microtubule nucleation and then capping the minus end of microtubules. γ-TuRCs are macromolecular assemblies with the core components as γ-tubulin and GCPs 2-6. In the past few years, a number of studies showed that CDK5RAP2 and GCP-WD interact with γ-TuRCs and regulate the complex functions: CDK5RAP2 regulates γ-TuRC-mediated microtubule nucleation and is required for interphase microtubule organization and mitotic astral microtubule growth; GCP-WD plays an important role in chromosome-mediated microtubule nucleation and mitotic spindle organization. The previous work in our laboratory has shown that CDK...[ Read more ]

Microtubules are one of the three major cytoskeletal structures in eukaryotic cells. γ-Tubulin ring complexes (γ-TuRCs) play key roles in microtubule organization by mediating microtubule nucleation and then capping the minus end of microtubules. γ-TuRCs are macromolecular assemblies with the core components as γ-tubulin and GCPs 2-6. In the past few years, a number of studies showed that CDK5RAP2 and GCP-WD interact with γ-TuRCs and regulate the complex functions: CDK5RAP2 regulates γ-TuRC-mediated microtubule nucleation and is required for interphase microtubule organization and mitotic astral microtubule growth; GCP-WD plays an important role in chromosome-mediated microtubule nucleation and mitotic spindle organization. The previous work in our laboratory has shown that CDK5RAP2 and GCP-WD are present in different γ-TuRCs. However, proteins associated with these γ-TuRC populations are still unknown.

The major goal of my project is the proteomic profiling and characterization of the γ-tubulin ring complex. In order to investigate the proteomes and functions of different populations of γ-TuRC and the mechanism of γ-TuRC dynamic change during cell cycle, a novel approach was applied to isolate various populations of γ-TuRC at specific cell cycle phases. Through mass spectrometry, I identify the proteome profiles of diverse γ-TuRCs and classify these proteins based on their known functions. Proteomic analysis and further functional research of these γ-TuRC associated proteins will help us obtain a better understanding of why there exists a variety of γ-TuRC and whether these different populations achieve distinct functions. Characterization of the identified γ-TuRC-associating proteins will provide insights on the function and regulation of CDK5RAP2- and GCP-WD-bound γ-TuRCs.