Recruitment of additional gamma tubulin/ gamma TuRC to the centrosome Authored: Matthews, L, 2008-11-11 14:53:40 Edited: Matthews, L, 2008-11-09 05:12:41 Microtubule nucleation at the centrosome is mediated by the gamma tubulin ring complex (gamma TuRC) (reviewed in Raynaud-Messina and Merdes, 2006; Wiese and Zheng, 2006). In humans, this large complex contains the tubulin superfamily member gamma-tubulin, five gamma complex proteins (GCP2-GPC6) and NEDD1/GCP-WD. A current model of the arrangement of subunits within the gamma-TuRC proposes that 6-7 TuSC subcomplexes are held together by the other Grip proteins (at an unknown stoichiometry), which together form the cap subunits. In many animal cells, the recruitment of gamma-tubulin complexes to the centrosome rapidly increases (3–5 fold ) before mitosis  to support the formation of new spindle microtubules (Khodjakov and Rieder 1999).  NEDD1/GCP-WD  plays  an essential role in recruitment of these complexes to the centrosomes (Haren et al., 2006;  Luders et al., 2006) and to the mitotic spindle (Luders et al., 2006). GCP-WD/NEDD1  associates directly with the  gamma-TuRC.  The carboxy-terminal half  binds to the gamma-TuRC whereas the amino-terminal half, corresponding to the WD-repeat domain,  is responsible for its attachment to the centrosome (Haren et al., 2006). Additional centrosomal proteins have also been implicated in the docking of gamma-TuRC to the centrosomes. CG-NAP/AKAP450  and kendrin  are  necessary for the initiation of microtubule nucleation and interact  with GCP2/GCP3 and GCP2, respectively (Takahashi et al., 2002).  Pericentrin  plays an important role in  microtubule organization in mitotic cells and anchors gamma- TuRC through domains that bind GCP2 and GCP3  (Zimmerman  et al. 2004). Ninein localizes to the centriole via its C-terminus and interacts with gamma-tubulin-containing complexes via its N-terminus. Pubmed10444067 Pubmed12221128 Pubmed15146056 Pubmed16378099 Pubmed16461362 Pubmed17038541 Pubmed17178454 Reactome Database ID Release 43380283 Reactome, http://www.reactome.org ReactomeREACT_15467 Reviewed: Merdes, A, 2008-11-17 13:55:29 centrosome gamma-tubulin complex Mature centrosomes enriched in gamma-TURC complexes