Centrosomal and non-centrosomal microtubules.
While microtubule (MT) arrays in cells are often focused at the centrosome, a variety of cell types contain a substantial number of non-centrosomal MTs. Epithelial cells, neurons, and muscle cells all contain arrays of non-centrosomal MTs that are critical for these cells' specialized functions. There are several routes by which non-centrosomal MTs can arise, including release from the centrosome, cytoplasmic assembly, breakage or severing, and stabilization from non-centrosomal sites. Once formed, MTs that are not tethered to the centrosome must be organized, which can be accomplished by means of self-organization or by capture and nucleation of MTs where they are needed. The presence of free MTs requires stabilization of minus ends, either by MT-associated proteins or by an end-capping complex. Although some of the basic elements of free MT formation and organization are beginning to be understood, a great deal of work is still necessary before we have a complete picture of how non-centrosomal MT arrays are assembled in specific cell types.
Keating
T J
TJ
Laboratory of Molecular Biology, University of Wisconsin, Madison 53706, USA.
Borisy
G G
GG
D000818:Animals; D002468:Cell Physiological Phenomena; D002477:Cells / Q000648:ultrastructure*; D018385:Centrosome / Q000502:physiology*; D008870:Microtubules / Q000502:physiology*