The mitotic cell cycle transition by which a cell in G2 commits to M phase. The process begins when the kinase activity of M cyclin/CDK complex reaches a threshold high enough for the cell cycle to proceed. This is accomplished by activating a positive feedback loop that results in the accumulation of unphosphorylated and active M cyclin/CDK complex.

The removal of tubulin heterodimers from one or both ends of a microtubule.

Assembly or disassembly of microtubules by the addition or removal of tubulin heterodimers from a microtubule.

Any process that modulates the frequency, rate or extent of the directed movement of a protein to a specific location.

The docking of a cytosolic centriole/basal body to the plasma membrane via the ciliary transition fibers. In some species this may happen via an intermediate step, by first docking to the ciliary vesicle via the ciliary transition fibers. The basal body-ciliary vesicle then relocates to the plasma membrane, followed by the ciliary vesicle fusing with the plasma membrane, effectively attaching the basal body to the plasma membrane.

A structure comprised of a core structure (in most organisms, a pair of centrioles) and peripheral material from which a microtubule-based structure, such as a spindle apparatus, is organized. Centrosomes occur close to the nucleus during interphase in many eukaryotic cells, though in animal cells it changes continually during the cell-division cycle.

A network of small fibers that surrounds the centrioles in cells; contains the microtubule nucleating activity of the centrosome.

Either of the ends of a spindle, where spindle microtubules are organized; usually contains a microtubule organizing center and accessory molecules, spindle microtubules and astral microtubules.

A centrosome-localized multiprotein complex composed of gamma-tubulin and other non-tubulin proteins assembled into a ring structure that is thought to be the unit of nucleation at the minus end of a microtubule. Gamma-tubulin small complexes are thought to be the core repeating units of the ring.

All of the contents of a cell excluding the plasma membrane and nucleus, but including other subcellular structures.

A structure comprised of a core structure (in most organisms, a pair of centrioles) and peripheral material from which a microtubule-based structure, such as a spindle apparatus, is organized. Centrosomes occur close to the nucleus during interphase in many eukaryotic cells, though in animal cells it changes continually during the cell-division cycle.

A cellular organelle, found close to the nucleus in many eukaryotic cells, consisting of a small cylinder with microtubular walls, 300-500 nm long and 150-250 nm in diameter. It contains nine short, parallel, peripheral microtubular fibrils, each fibril consisting of one complete microtubule fused to two incomplete microtubules. Cells usually have two centrioles, lying at right angles to each other. At division, each pair of centrioles generates another pair and the twin pairs form the pole of the mitotic spindle.

The part of the cytoplasm that does not contain organelles but which does contain other particulate matter, such as protein complexes.

A membrane-tethered, short cylindrical array of microtubules and associated proteins found at the base of a eukaryotic cilium (also called flagellum) that is similar in structure to a centriole and derives from it. The cilium basal body is the site of assembly and remodelling of the cilium and serves as a nucleation site for axoneme growth. As well as anchoring the cilium, it is thought to provide a selective gateway regulating the entry of ciliary proteins and vesicles by intraflagellar transport.

The region of a polarized cell that forms a tip or is distal to a base. For example, in a polarized epithelial cell, the apical region has an exposed surface and lies opposite to the basal lamina that separates the epithelium from other tissue.