Post-translational modifications to Toxoplasma gondii α- and β-tubulins include novel C-terminal methylation

Hui Xiao, Kamal El Bissati, Pascal Verdier-Pinard, Berta Burd, Hongshan Zhang, Kami Kim, Andras Fiser, Ruth Hogue Angeletti, Louis M. Weiss

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

Toxoplasma gondii is an apicomplexan of both medical and veterinary importance which is classified as an NIH Category B priority pathogen. It is best known for its ability to cause congenital infection in immune competent hosts and encephalitis in immune compromised hosts. The highly stable and specialized microtubule-based cytoskeleton participates in the invasion process. The genome encodes three isoforms of both α- and β-tubulin and we show that the tubulin is extensively altered by specific post-translational modifications (PTMs) in this paper. T. gondii tubulin PTMs were analyzed by mass spectrometry and immunolabeling using specific antibodies. The PTMs identified on α-tubulin included acetylation of Lys40, removal of the last C-terminal amino acid residue Tyr453 (detyrosinated tubulin) and truncation of the last five amino acid residues. Polyglutamylation was detected on both α- and β-tubulins. An antibody directed against mammalian α-tubulin lacking the last two C-terminal residues (Δ2-tubulin) labeled the apical region of this parasite. Detyrosinated tubulin was diffusely present in subpellicular microtubules and displayed an apparent accumulation at the basal end. Methylation, a PTM not previously described on tubulin, was also detected. Methylated tubulins were not detected in the host cells, human foreskin fibroblasts, suggesting that this may be a modification specific to the Apicomplexa.

Original languageEnglish (US)
Pages (from-to)359-372
Number of pages14
JournalJournal of Proteome Research
Volume9
Issue number1
DOIs
StatePublished - Jan 4 2010

Keywords

  • Conoid
  • Cytoskeleton
  • Microtubules
  • Post-translational modification
  • Proteomics
  • Toxoplasma gondii
  • Tubulin

ASJC Scopus subject areas

  • Biochemistry
  • Chemistry(all)

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