The two alpha-tubulin isotypes in budding yeast have opposing effects on microtubule dynamics in vitro

EMBO Rep. 2003 Jan;4(1):94-9. doi: 10.1038/sj.embor.embor716.


The yeast Saccharomyces cerevisiae has two genes for alpha-tubulin, TUB1 and TUB3, and one beta-tubulin gene, TUB2. The gene product of TUB3, Tub3, represents approximately 10% of alpha-tubulin in the cell. We determined the effects of the two alpha-tubulin isotypes on microtubule dynamics in vitro. Tubulin was purified from wild-type and deletion strains lacking either Tub1 or Tub3, and parameters of microtubule dynamics were examined. Microtubules containing Tub3 as the only alpha-tubulin isotype were less dynamic than wild-type microtubules, as shown by a shrinkage rate and catastrophe frequency that were about one-third of that for wild-type microtubules. Conversely, microtubules containing Tub1 as the only alpha-tubulin isotype were more dynamic than wild-type microtubules, as shown by a shrinkage rate that was 50% higher and a catastrophe frequency that was 30% higher than those of wild-type microtubules. The results suggest that a role of Tub3 in budding yeast is to control microtubule dynamics.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Biopolymers
  • Chromatography, Affinity
  • Electrophoresis, Polyacrylamide Gel
  • Microtubules / chemistry
  • Microtubules / metabolism*
  • Microtubules / ultrastructure
  • Molecular Sequence Data
  • Motion
  • Protein Conformation
  • Protein Isoforms / chemistry
  • Protein Isoforms / genetics
  • Protein Isoforms / physiology
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / physiology*
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Structure-Activity Relationship


  • Biopolymers
  • Protein Isoforms
  • Saccharomyces cerevisiae Proteins
  • Tub1 protein, S cerevisiae
  • Tub3 protein, S cerevisiae