The two alpha-tubulin isotypes in budding yeast have opposing effects on microtubule dynamics in vitro.
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.
Bode
Claudia J
CJ
Department of Molecular Biosciences, University of Kansas, Lawrence 66045, USA.
Gupta
Mohan L
ML
Suprenant
Kathy A
KA
Himes
Richard H
RH
D000595:Amino Acid Sequence; D001704:Biopolymers; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009038:Motion; D011487:Protein Conformation; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship
D001704:Biopolymers; D020033:Protein Isoforms; D029701:Saccharomyces cerevisiae Proteins; C475498:Tub1 protein, S cerevisiae; C475499:Tub3 protein, S cerevisiae