Organizational Properties of the Pericentriolar Material

The centrosome is the major microtubule-organizing centre of animal cells. It participates in a number of crucial cellular functions including cell motility, intracellular transport, mitotic spindle assembly/positioning and cilia formation. Centrosome is composed of pair of ninefold symmetric centrioles surrounded by pericentriolar material, or PCM. PCM organization undergoes a series of dramatic changes in its organization and function as cells progress through the cell cycle. Indeed, the rather small interphase centrosome increases dramatically in size and microtubule nucleation capacity from interphase to mitosis, a process referred to as centrosome maturation. Until very recently, the PCM was thought to be largely amorphous. However, it has been elegantly demonstrated in several super-resolution studies that the PCM is highly organized and that the higher-order organizational properties are conserved from flies to humans. In this book chapter, we review current knowledge on the organization and composition of PCM in both interphase and mitosis and discuss how the centrosome landscape is altered through post-translational modifications, mainly mitotic phosphorylation, during centrosome maturation.