Toxoplasma tgatg9 is critical for autophagy and long-term persistence in tissue cysts

David Smith, Geetha Kannan, Isabelle Coppens, Fengrong Wang, Hoa Mai Nguyen, Aude Cerutti, Einar B. Olafsson, Patrick A. Rimple, Tracey L. Schultz, Nayanna M.Mercado Soto, Manlio Di Cristina, Sébastien Besteiro, Vern B. Carruthers

Research output: Contribution to journalArticlepeer-review


Many of the world’s warm-blooded species are chronically infected with Toxoplasma gondii tissue cysts, including an estimated one third of the global human population. The cellular processes that permit long-term persistence within the cyst are largely unknown for T. gondii and related coccidian parasites that impact human and animal health. Herein we show that genetic ablation of TgATG9 substantially reduces canonical autophagy and compromises bradyzoite viability. Transmission electron microscopy revealed numerous structural abnormalities occurring in ∆atg9 bradyzoites. Intriguingly, abnormal mitochondrial networks were observed in TgATG9-deficient bradyzoites, some of which contained numerous different cytoplasmic components and organelles. ∆atg9 bradyzoite fitness was drastically compromised in vitro and in mice, with very few brain cysts identified in mice 5 weeks postinfection. Taken together, our data suggests that TgATG9, and by extension autophagy, is critical for cellular homeostasis in bradyzoites and is necessary for long-term persistence within the cyst of this coccidian parasite.

Original languageEnglish (US)
Article numbere59384
StatePublished - Apr 2021


  • ATG9
  • Apicomplexa
  • Chronic infection
  • Parasite
  • Protozoan

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)


Dive into the research topics of 'Toxoplasma tgatg9 is critical for autophagy and long-term persistence in tissue cysts'. Together they form a unique fingerprint.

Cite this