GammaTuRC

gammaTuRC, or gamma-tubulin ring complex, is a multiprotein complex that nucleates microtubules in eukaryotic cells. It provides a physical template that seeds the assembly of microtubule minus ends and concentrates at the centrosome pericentriolar material and spindle poles during cell division. By organizing microtubule nucleation, gammaTuRC helps establish the mitotic spindle and ensures accurate chromosome segregation.

The core component in many organisms is the gamma-tubulin small complex (gammaTuSC), comprising gamma-tubulin and GCP2 and GCP3. In most species this core assembles with additional gamma-tubulin complex proteins (GCP4–GCP6) to form the larger gammaTuRC. Accessory factors such as NEDD1 (also called GCP-WD) and MZT1 aid targeting and stability, while centrosomal scaffolds such as CDK5RAP2 (Cep215) and other pericentriolar material proteins anchor gammaTuRC to the centrosome.

The gammaTuRC adopts a ring-like architecture that serves as a template matching the microtubule's structure, enabling efficient nucleation of microtubules with a defined minus end. Nucleation is further regulated through the cell cycle and by networks such as the augmin complex, which recruits gammaTuRC to existing microtubules to promote branching nucleation within the spindle.

gammaTuRC is highly conserved among eukaryotes. Proper function of the complex is essential for spindle assembly and chromosome segregation; its misregulation can contribute to mitotic defects, aneuploidy, and cancer.