What is "centrosome"

Centrosome \Cen"tro*some`\, n. [Gr. ? center + -? the body.] (Biol.) A peculiar rounded body lying near the nucleus of a cell. It is regarded as the dynamic element by means of which the machinery of cell division is organized.

1889, from German centrosoma (1888), coined by German zoologist Theodor Boveri (1862-1915), from centro- (see center (n.)) + -some (3)).

n. (context cytology English) An organelle, near the nucleus in the cytoplasm of most organisms, that controls the organization of its microtubules

n. small region of cytoplasm adjacent to the nucleus; contains the centrioles and serves to organize the microtubules [syn: central body]

In cell biology, the centrosome (Latin centrum 'center' + Greek sōma 'body') is an organelle that serves as the main microtubule organizing center (MTOC) of the animal cell as well as a regulator of cell-cycle progression. The centrosome is thought to have evolved only in the metazoan lineage of eukaryotic cells. Fungi and plants lack centrosomes and therefore use other MTOC structures to organize their microtubules. Although the centrosome has a key role in efficient mitosis in animal cells, it is not essential in certain fly and flatworm species.

Centrosomes are composed of two orthogonally arranged centrioles surrounded by an amorphous mass of protein termed the pericentriolar material (PCM). The PCM contains proteins responsible for microtubule nucleation and anchoring including γ- tubulin, pericentrin and ninein. In general, each centriole of the centrosome is based on a nine triplet microtubule assembled in a cartwheel structure, and contains centrin, cenexin and tektin.