Multiple alpha-tubulin isoforms in cilia and cytoskeleton of Tetrahymena pyriformis generated by post-translational modifications. Studies during reciliation

Eur J Biochem. 1991 Jan 30;195(2):487-94. doi: 10.1111/j.1432-1033.1991.tb15729.x.

Abstract

alpha-Tubulin microheterogeneity was studied in Tetrahymena pyriformis. Using two-dimensional electrophoretic analysis, we found between five and seven alpha-tubulin and four beta-tubulin isoforms in cilia and four or five alpha-tubulins and two beta-tubulins in cytoskeleton. Immunoblotting assay with anti-(acetyl alpha-tubulin) monoclonal antibody 6-11B-1 and [3H]acetate labelling revealed that the alpha-tubulin isoforms are post-translationally modified by acetylation. Our results also show that tubulins in the soluble cytoplasmic fraction are not acetylated. Nevertheless, a slight reaction with the antibody 6-11 B-1 can be observed in the taxol and vinblastine-treated cytoplasmic pool. Pulse/chase experiments using [35S]methionine during cell reciliation have demonstrated that the basic alpha-tubulin isoforms are converted into acidic isoforms in the absence of protein synthesis, suggesting that the basic alpha-tubulin is the precursor of the acidic forms which are found in cilia and cytoskeleton. In-vivo-translation selection demonstrated the existence of a single precursor molecule which corresponded to the most basic alpha-tubulin. Taken together, our results provide evidence for the existence of post-translational modifications, namely acetylation. Nevertheless, other post-translational mechanisms involved in the biosynthesis of microtubules of cilia and cytoskeleton are required to explain the whole alpha-tubulin heterogeneity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / metabolism
  • Acetylation
  • Animals
  • Antibodies, Monoclonal
  • Cilia / metabolism*
  • Cytoskeleton / metabolism*
  • Genetic Variation
  • Isomerism
  • Methionine / metabolism
  • Protein Processing, Post-Translational*
  • RNA, Messenger / biosynthesis
  • Regeneration / genetics*
  • Sulfur Radioisotopes
  • Tetrahymena pyriformis / genetics*
  • Tritium
  • Tubulin / biosynthesis
  • Tubulin / genetics*

Substances

  • Acetates
  • Antibodies, Monoclonal
  • RNA, Messenger
  • Sulfur Radioisotopes
  • Tubulin
  • Tritium
  • Methionine