Delta-tubulin and epsilon-tubulin: two new human centrosomal tubulins reveal new aspects of centrosome structure and function.
The centrosome organizes microtubules, which are made up of alpha-tubulin and beta-tubulin, and contains centrosome-bound gamma-tubulin, which is involved in microtubule nucleation. Here we identify two new human tubulins and show that they are associated with the centrosome. One is a homologue of the Chlamydomonas delta-tubulin Uni3, and the other is a new tubulin, which we have named epsilon-tubulin. Localization of delta-tubulin and epsilon-tubulin to the centrosome is independent of microtubules, and the patterns of localization are distinct from each other and from that of gamma-tubulin. Delta-tubulin is found in association with the centrioles, whereas epsilon-tubulin localizes to the pericentriolar material. epsilon-Tubulin exhibits a cell-cycle-specific pattern of localization, first associating with only the older of the centrosomes in a newly duplicated pair and later associating with both centrosomes. epsilon-Tubulin thus distinguishes the old centrosome from the new at the level of the pericentriolar material, indicating that there may be a centrosomal maturation event that is marked by the recruitment of epsilon-tubulin.
Chang
P
P
Department of Biological Sciences, Stanford University, Stanford, California 94305-5020, USA.
Stearns
T
T
D000970:Antineoplastic Agents / Q000494:pharmacology; D002453:Cell Cycle / Q000502:physiology; D002478:Cells, Cultured; D018385:Centrosome / Q000737:chemistry* / Q000502:physiology*; D006801:Humans; D008870:Microtubules / Q000737:chemistry / Q000187:drug effects / Q000502:physiology; D008969:Molecular Sequence Data; D015739:Nocodazole / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D014404:Tubulin / Q000032:analysis / Q000235:genetics / Q000276:immunology
D000970:Antineoplastic Agents; D014404:Tubulin; D015739:Nocodazole