γ-Tubulin Antibody #5886

Globular tubulin subunits comprise the microtubule building block, with α/β-tubulin heterodimers forming the tubulin subunit common to all eukaryotic cells. As a critical part of the microtubule-organizing center (MTOC), the third member of the tubulin superfamily, γ-tubulin, is required for microtubule nucleation as well as centrosome duplication and spindle assembly (1,2, reviewed in 3). γ-tubulin forms complexes of two different sizes: γ-tubulin small complex (γ-TuSC) and the larger γ-tubulin ring complex (γ-TuRC). Each complex consists of a number of γ-tubulin complex proteins (GCPs) with γ-tubulin itself being considered GCP1. GCP2-6 all share sequence similarity in 5 different regions and it is thought that these areas could play a role in the proper folding of the proteins (4). γ-TuSC is composed of two γ-tubulin molecules as well as GCP2 and GCP3. γ-TuRC is made up of a ring of multiple copies of γ-TuSC in addition to GCP4, 5, and 6. Another protein, GCP-WD/NEDD1, which lacks sequence similarity with the other GCPs, associates with the γ-TuRC. GCP-WD/NEDD1 has been shown to regulate localization of the γ-TuSC to spindles and centrosomes (5-8). In mammals, phosphorylation of γ-tubulin at Ser131 by SADB controls the activity of the γ-TuRC. The hypothesis is that this phosphorylation stabilizes the protein in a conformation that stimulates centrosome amplification (9).