The microtubule (MT) network is a major component of the cellular cytoskeleton. Its importance towards cellular function is reflected in its roles in cell proliferation, intracellular transport, and cell migration. A crucial element of MT organization is the γ-tubulin ring complex (γTuRC). This evolutionarily conserved entity is responsible for microtubule nucleation at the centrosomes, near the mitotic chromatin, and also within existing spindle microtubules. The γTuRC also acts as a stability factor for microtubules by virtue of its MT-minus end capping function, thereby preventing depolymerization. It is well known that the γTuRC contains members of a conserved protein family called GCPs. Recently several novel γTuRC-binding proteins are identified, such as CDK5RAP2, GCP-WD and MOZAR...[ Read more ]

The microtubule (MT) network is a major component of the cellular cytoskeleton. Its importance towards cellular function is reflected in its roles in cell proliferation, intracellular transport, and cell migration. A crucial element of MT organization is the γ-tubulin ring complex (γTuRC). This evolutionarily conserved entity is responsible for microtubule nucleation at the centrosomes, near the mitotic chromatin, and also within existing spindle microtubules. The γTuRC also acts as a stability factor for microtubules by virtue of its MT-minus end capping function, thereby preventing depolymerization. It is well known that the γTuRC contains members of a conserved protein family called GCPs. Recently several novel γTuRC-binding proteins are identified, such as CDK5RAP2, GCP-WD and MOZART1. However, despite the elucidation of key roles for these proteins in centrosomal attachment, MT nucleation, and mitotic spindle organization, it remains unclear how their roles are integrated in the regulation of the γTuRC. In our present studies, we have uncovered that despite their direct binding to the γTuRC, CDK5RAP2, GCP-WD and MOZART1 exist in different γTuRC populations, and they also have distinct γTuRC binding preferences in different stages of cell cycle. Our data suggests that CDK5RAP2, GCP-WD and MOZART1 may be under distinct control for interacting with the γTuRC.