The{gamma} -tubulin ring complex ({gamma}-TuRC) is an essential regulator of centrosomal and acentrosomal microtubule formation 1-4. Metazoan{gamma} -TuRCs isolate as [~]2 MDa complexes containing the conserved proteins{gamma} -tubulin, GCP2 and GCP3, as well as the expanded subunits GCP4, GCP5, and GCP6 3,5,6. However, in current structural models,{gamma} -TuRCs assemble solely... Show more