The ubiquitin proteome of Toxoplasma gondii reveals roles for protein ubiquitination in cell-cycle transitions

Natalie C. Silmon De Monerri, Rama R. Yakubu, Allan L. Chen, Peter J. Bradley, Edward Nieves, Louis M. Weiss, Kami Kim

Research output: Contribution to journalArticle

17 Scopus citations


Protein ubiquitination plays key roles in protein turnover, cellular signaling, and intracellular transport. The genome of Toxoplasma gondii encodes ubiquitination machinery, but the roles of this posttranslational modification (PTM) are unknown. To examine the prevalence and function of ubiquitination in T. gondii, we mapped the ubiquitin proteome of tachyzoites. Over 500 ubiquitin-modified proteins, with almost 1,000 sites, were identified on proteins with diverse localizations and functions. Enrichment analysis demonstrated that 35% of ubiquitinated proteins are cell-cycle regulated. Unexpectedly, most classic cell-cycle regulators conserved in T. gondii were not detected in the ubiquitinome. Furthermore, many ubiquitinated proteins localize to the cytoskeleton and inner membrane complex, a structure beneath the plasma membrane facilitating division and host invasion. Comparing the ubiquitinome with other PTM proteomes reveals waves of PTM enrichment during the cell cycle. Thus, T. gondii PTMs are implicated as critical regulators of cell division and cell-cycle transitions.

Original languageEnglish (US)
Pages (from-to)621-633
Number of pages13
JournalCell Host and Microbe
Issue number5
StatePublished - Nov 11 2015


ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Virology

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