Hyperglutamylation of tubulin can either stabilize or destabilize microtubules in the same cell

Eukaryot Cell. 2010 Jan;9(1):184-93. doi: 10.1128/EC.00176-09. Epub 2009 Aug 21.

Abstract

In most eukaryotic cells, tubulin is subjected to posttranslational glutamylation, a conserved modification of unclear function. The glutamyl side chains form as branches of the primary sequence glutamic acids in two biochemically distinct steps: initiation and elongation. The length of the glutamyl side chain is spatially controlled and microtubule type specific. Here, we probe the significance of the glutamyl side chain length regulation in vivo by overexpressing a potent side chain elongase enzyme, Ttll6Ap, in Tetrahymena. Overexpression of Ttll6Ap caused hyperelongation of glutamyl side chains on the tubulin of axonemal, cortical, and cytoplasmic microtubules. Strikingly, in the same cell, hyperelongation of glutamyl side chains stabilized cytoplasmic microtubules and destabilized axonemal microtubules. Our observations suggest that the cellular outcomes of glutamylation are mediated by spatially restricted tubulin interactors of diverse nature.

Publication types

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

MeSH terms

  • Animals
  • Axoneme / metabolism
  • Axoneme / ultrastructure
  • Cilia / metabolism
  • Cilia / ultrastructure
  • Glutamic Acid / chemistry
  • Glutamic Acid / metabolism*
  • Microtubules / metabolism*
  • Protein Processing, Post-Translational*
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Tetrahymena thermophila* / cytology
  • Tetrahymena thermophila* / metabolism
  • Tubulin / chemistry
  • Tubulin / metabolism*
  • Tubulin Modulators / metabolism

Substances

  • Protozoan Proteins
  • Recombinant Fusion Proteins
  • Tubulin
  • Tubulin Modulators
  • Glutamic Acid