Structure and duplication of the centrosome

J Azimzadeh, M Bornens - Journal of cell science, 2007 - journals.biologists.com
J Azimzadeh, M Bornens
Journal of cell science, 2007journals.biologists.com
The architecture of the microtubule array in differentiated cell types results not only from the
dynamic behaviour of MTs but also from a balance between MT nucleation and MT-
anchoring activities at the centrosome. During interphase, MTs are nucleated in the matrix
associated with both mother and daughter centrioles, but only the mother centriole is able to
anchor them on its associated sub-distal appendages (Piel et al., 2000). Microtubules are
nucleated by the-tubulin ring complex (-TuRC).-Tubulin is present throughout the cell cycle …
The architecture of the microtubule array in differentiated cell types results not only from the dynamic behaviour of MTs but also from a balance between MT nucleation and MT-anchoring activities at the centrosome. During interphase, MTs are nucleated in the matrix associated with both mother and daughter centrioles, but only the mother centriole is able to anchor them on its associated sub-distal appendages (Piel et al., 2000). Microtubules are nucleated by the-tubulin ring complex (-TuRC).-Tubulin is present throughout the cell cycle in the matrix, close to the proximal walls of centrioles. Its levels increase dramatically prior to mitosis, concomitantly with the recruitment of MT-associated proteins required for mitotic spindle formation. This process, centrosome maturation, is under the control of the Polo-like and Aurora A kinases (for a review, see Blagden and Glover, 2003).
Following their nucleation by the-TuRC, MTs are either released into the cytoplasm or recaptured and anchored at the centrosome. Several different MT-anchoring mechanisms have been proposed. The subdistal appendages of the mother centriole are thought to be a major site for MT anchoring, and this activity requires ninein, a component of sub-distal appendages (Mogensen et al., 2000). In addition, ninein has been shown to interact with the-TuRC and thus also ensures a link with MT nucleation (Delgehyr et al., 2005). Other MT anchoring complexes are seemingly also present in the matrix, although preferentially associate with the mother centriole. Among them, the p150glued subunit of the dynactin complex seems to play an important role in collaboration with the MT-associated protein EB1 (Askham et al., 2002).
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