gamma-tubulin ring complex

Definition

Target type: cellularcomponent

A complex of gamma tubulin and associated proteins thought to be formed by multimerization of gamma-tubulin small complexes. An example of this structure is found in Schizosaccharomyces pombe. [GOC:mtg_sensu, PMID:12134075, PMID:17021256]

The gamma-tubulin ring complex (γTuRC) is a multi-protein complex essential for microtubule nucleation in eukaryotic cells. It serves as a template for the assembly of microtubules, ensuring their proper organization and function. The γTuRC is found in the centrosome, a microtubule organizing center (MTOC), and other microtubule-nucleating sites in the cell. It is composed of several key components, including:

* **γ-tubulin:** The core component of the complex, γ-tubulin is a tubulin isotype that acts as a template for the assembly of α- and β-tubulin heterodimers, the building blocks of microtubules. It forms a ring-like structure at the minus end of microtubules, where polymerization initiates.
* **γ-tubulin small complex (γTuSC):** This subcomplex is composed of three proteins: γ-tubulin, GCP2, and GCP3. It acts as a seed for the assembly of the full γTuRC and plays a crucial role in microtubule nucleation.
* **GCP4-8:** These proteins associate with the γTuSC and form a larger complex called the γTuRC. They contribute to the stability and functionality of the γTuRC, ensuring its proper interaction with other cellular components and microtubules.
* **GCP1-3:** These proteins are thought to regulate the activity of the γTuRC and may play a role in microtubule organization and dynamics.

The γTuRC exhibits a distinct architecture. The γ-tubulin molecules in the complex form a ring-like structure with a central hole. This ring serves as a template for the assembly of α- and β-tubulin heterodimers, promoting their ordered arrangement into microtubules. The other γTuRC components, particularly GCP4-8, associate with the γ-tubulin ring and stabilize its structure, ensuring its proper functionality in microtubule nucleation.

The γTuRC is a highly dynamic complex, undergoing constant assembly and disassembly. Its activity is regulated by various cellular signaling pathways and factors, including phosphorylation, post-translational modifications, and protein-protein interactions. These regulatory mechanisms ensure the timely and precise nucleation of microtubules in response to cellular needs.

The γTuRC plays a pivotal role in a wide range of cellular processes, including cell division, cell migration, organelle transport, and cell signaling. Defects in the γTuRC are associated with various human diseases, including cancer and neurodegenerative disorders.'
"

Proteins (1)

Compounds (1)