In glia and most other non-neuronal cells, however, the minus ends of MTs are usually bound at the site of nucleation, which is associated with the pericentriolar complex of the cell, a site often called the microtubule-organizing center (MTOC) [5]. Anchoring of MT minus ends helps to establish and maintain the polarity of cellular MTs. Anchoring and nucleation of MTs appear to require a third class of tubulin, γ-tubulin, which is detectable only as part of the pericentriolar complex [5].