In cell biology, the centrosome (Latin centrum 'center' + Greek sōma 'body') (archaically cytocentre[1]) 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 provides structure for the cell. The centrosome is thought to have evolved only in the metazoan lineage of eukaryotic cells.[2]Fungi and plants lack centrosomes and therefore use other structures to organize their microtubules.[3][4] Although the centrosome has a key role in efficient mitosis in animal cells, it is not essential in certain fly and flatworm species.[5][6][7]
Centrosomes are composed of two centrioles arranged at right angles to each other, and surrounded by a dense, highly structured[8] mass of protein termed the pericentriolar material (PCM). The PCM contains proteins responsible for microtubule nucleation and anchoring[9] — 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.[10]
In many cell types, the centrosome is replaced by a cilium during cellular differentiation. However, once the cell starts to divide, the cilium is replaced again by the centrosome.[11]
^Jaspersen, S. L.; Winey, M. (2004). "THE BUDDING YEAST SPINDLE POLE BODY: Structure, Duplication, and Function". Annual Review of Cell and Developmental Biology. 20 (1): 1–28. doi:10.1146/annurev.cellbio.20.022003.114106. PMID15473833.
^Rieder, C. L.; Faruki, S.; Khodjakov, A. (Oct 2001). "The centrosome in vertebrates: more than a microtubule-organizing center". Trends in Cell Biology. 11 (10): 413–419. doi:10.1016/S0962-8924(01)02085-2. ISSN0962-8924. PMID11567874.