Control at the cell center: the role of spindle poles in cytoskeletal organization and cell cycle regulation.

Microtubule organizing centres (MTOCs), which include fungal spindle pole bodies and centrosome in higher eukaryotes, are a structurally diverse group of organelles that share a conserved role in microtubule nucleation and spindle formation. However, recent studies propose that the function of MTOC components extends far beyond these established roles. Numerous cell cycle regulators, checkpoint proteins and microtubule plus tip binding proteins localize to MTOCs during the cell cycle, suggesting that these organelles serve as cellular scaffolds. In addition, several MTOC components such as gamma-tubulin and its associating proteins have been directly implicated in the control of cell cycle progression, activation of checkpoint responses and the regulation of microtubule organization and dynamics. Collectively, these findings implicate MTOCs as cellular control centers that coordinate events at both microtubule minus ends and plus ends with the cell cycle. In this review, we discuss recent studies that support a role for MTOC components, in particular gamma-tubulin, in cell cycle progression, checkpoint response and the coordination of microtubule organization and dynamics.