Gamma-tubulin at ten: progress and prospects.
The existence of gamma-tubulin was first reported approximately ten years ago, and it is appropriate to review the progress that has been made in gamma-tubulin research and to discuss some of the unanswered questions about gamma-tubulin function. gamma-Tubulin is ubiquitous in eukaryotes and is generally quite conserved. Two highly divergent gamma-tubulins have been discovered, however, one in Saccharomyces cerevisiae and one in Caenorhabditis elegans. Several organisms have two gamma-tubulin genes. In Drosophila melanogaster, the two gamma-tubulins differ significantly in sequence and expression pattern. In other organisms the two gamma-tubulins are almost identical and expression patterns have not been determined. gamma-Tubulin is located at microtubule organizing centers in many organisms, and it is also frequently associated with the mitotic spindle. gamma-Tubulin is essential for the formation of functional mitotic spindles in all organisms that have been examined to date. In animal cells, complexes containing gamma-tubulin are located at microtubule organizing centers where they nucleate the assembly of microtubules. In spite of the considerable progress that has been made in gamma-tubulin research important questions remain to be answered. The exact mechanisms of microtubule nucleation by gamma-tubulin complexes remain to be resolved as do the mechanisms by which microtubule nucleation from gamma-tubulin complexes is regulated. Finally, there is evidence that gamma-tubulin has important functions in addition to microtubule nucleation, and these functions are just beginning to be investigated.
Oakley
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BR
Department of Molecular Genetics, The Ohio State University, 484 W. 12th Ave., Columbus, OH 43210, USA. oakley.2@osu.edu
Akkari
Y N
YN
D000818:Animals; D018385:Centrosome / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D022101:Microtubule-Organizing Center / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism; D010802:Phylogeny; D011485:Protein Binding; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D008941:Spindle Apparatus / Q000378:metabolism; D014404:Tubulin / Q000235:genetics / Q000378:metabolism*
D029721:Drosophila Proteins; C469730:Grip75 protein, Drosophila; D008869:Microtubule-Associated Proteins; C465662:SPC97 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014404:Tubulin