The heat-shock protein 90 (HSP90) from tobacco VBIo cells specifically binds to nitrocellulose that had been coated with polymerized microtubules or tubulin dimers. HSP90 is expressed preferentially during cell division and becomes downregulated during cell elongation. HSP90 cofractionates with tubulin dimers during affinity chromatography with sepharose coupled to the tubulin-binding drug ethy...

What is it? γ-Tubulin is a member of the tubulin superfamily and is required for nucleating the polymerization of microtubules in vivo. Microtubules are dynamic cytoskeletal polymers that assemble from two other members of the tubulin superfamily, α-tubulin and βtubulin. Microtubules make up the mitotic and meiotic spindles, and are important for establishing cell polarity and vesicle trafficki...

Nucleoside diphosphate (NDP) kinase has been postulated to generate GTP from the GDP bound to tubulin. The purified chick brain enzyme was studied with respect to its kinetic parameters, and the protein-protein interactions between the NDP kinase and tubulin were examined. No specific interaction is observed between the enzyme and assembled microtubules, tubulin dimers, or tubulin-microtubule-a...

The kinesin-13 motor protein family members drive the removal of tubulin from microtubules (MTs) to promote MT turnover. A point mutation of the kinesin-13 family member mitotic centromere-associated kinesin/Kif2C (E491A) isolates the tubulin-removal conformation of the motor, and appears distinct from all previously described kinesin-13 conformations derived from nucleotide analogues. The E491...

The centrosome is the primary microtubule organizing centre of the cell. gamma-tubulin is a core component of the centrosome and is required for microtubule nucleation and centrosome function. The recruitment of gamma-tubulin to centrosomes is mediated by its interaction with NEDD1, a WD40-repeat containing protein. Here we demonstrate that NEDD1 is likely to be oligomeric in vivo and binds dir...

gamma-tubulin exists in two related complexes in Drosophila embryo extracts (Moritz, M., Y. Zheng, B.M. Alberts, and K. Oegema. 1998. J. Cell Biol. 142:1- 12). Here, we report the purification and characterization of both complexes that we name gamma-tubulin small complex (gammaTuSC; approximately 280,000 D) and Drosophila gammaTuRC ( approximately 2,200,000 D). In addition to gamma-tubulin, th...

Axin is known to have an important role in the degradation of beta-catenin in the Wnt pathway. Here, we reveal a new function of Axin at the centrosome. Axin was localized to the centrosome in various cell lines and formed a complex with gamma-tubulin. Knockdown of Axin reduced the localization of gamma-tubulin and gamma-tubulin complex protein 2-components of the gamma-tubulin ring complex-to ...

We have investigated the sites of microtubule (MT) assembly in neurons during axon growth by taking advantage of the relationship between the proportion of tyrosinated alpha-tubulin (tyr-tubulin) in MTs and their age. Specifically, young (newly assembled) MTs contain more tyr-tubulin than older (more long-lived) MTs. To quantify the relative proportion of tyr-tubulin in MTs, cultured rat sympat...

Assembly-competent tubulin was purified from the cytoplasm of unfertilized and parthogenetically activated oocytes, and from isolated meiotic spindles of the surf clam, Spisula solidissima. At 22 degrees C or 37 degrees C, Spisula tubulin assembled into 48-51-nm macrotubules during the first cycle of polymerization and 25-nm microtubules during the third and subsequent cycles of assembly. Macro...

We have used monoclonal antibodies specific for acetylated and unacetylated a-tubulin to characterize the acetylated a-tubulin isotype of Physarum polycephalum, its expression in the life cycle, and its localization in particular microtubular organelles. We have used the monoclonal antibody 6-11B-1 (Piperno, G., and M. T. Fuller, 1985, J. Cell Biol., 101:2085-2094) as the probe for acetylated c...