Polyglycylation of tubulin is essential and affects cell motility and division in Tetrahymena thermophila

J Cell Biol. 2000 May 29;149(5):1097-106. doi: 10.1083/jcb.149.5.1097.


We analyzed the role of tubulin polyglycylation in Tetrahymena thermophila using in vivo mutagenesis and immunochemical analysis with modification-specific antibodies. Three and five polyglycylation sites were identified at glutamic acids near the COOH termini of alpha- and beta-tubulin, respectively. Mutants lacking all polyglycylation sites on alpha-tubulin have normal phenotype, whereas similar sites on beta-tubulin are essential. A viable mutant with three mutated sites in beta-tubulin showed reduced tubulin glycylation, slow growth and motility, and defects in cytokinesis. Cells in which all five polyglycylation sites on beta-tubulin were mutated were viable if they were cotransformed with an alpha-tubulin gene whose COOH terminus was replaced by the wild-type COOH terminus of beta-tubulin. In this double mutant, beta-tubulin lacked detectable polyglycylation, while the alpha-beta tubulin chimera was hyperglycylated compared with alpha-tubulin in wild-type cells. Thus, the essential function of polyglycylation of the COOH terminus of beta-tubulin can be transferred to alpha-tubulin, indicating it is the total amount of polyglycylation on both alpha- and beta-tubulin that is essential for survival.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal
  • Cell Division / physiology
  • Cell Movement / physiology*
  • Cell Survival / physiology
  • Cilia / physiology
  • Glycosylation
  • Microscopy, Confocal
  • Microtubules / metabolism
  • Molecular Motor Proteins / metabolism
  • Molecular Sequence Data
  • Mutagenesis / physiology
  • Phenotype
  • Tetrahymena thermophila / cytology*
  • Tetrahymena thermophila / genetics
  • Tetrahymena thermophila / metabolism
  • Tubulin / genetics*
  • Tubulin / immunology
  • Tubulin / metabolism*


  • Antibodies, Monoclonal
  • Molecular Motor Proteins
  • Tubulin