Tuesday, May 13, 2025
5/13/2025
Functional characterization of the T. cruzi amastigote flagellum - PROJECT SUMMARY The kinetoplastid protozoan and causative agent of human Chagas disease, Trypanosoma cruzi, has a complex life cycle that involves both mammalian and insect hosts. To adapt to disparate host environments, these uniflagellate organisms undergo marked morphological and metabolic changes, transitioning between elongated motile extracellular stages (epimastigote, trypomastigote) and ovoid non-motile intracellular forms (amastigote). In mammals, motile trypomastigotes invade diverse cell types and undergo a developmental transition to form amastigotes that replicate in the cytoplasm of infected host cells. Accompanying the loss of motility in the intracellular amastigote stage of T. cruzi, is a dramatic shortening of the flagellum. With no role in motility, little attention has been given to the amastigote flagellum. However, with growing evidence that flagella of trypanosomatids have important sensory roles, we posit that the T. cruzi amastigote flagellum may also function in environmental sensing and/or nutrient acquisition. Consistent with this suggestion, we have discovered that the T. cruzi amastigote flagellum is capable of movement and engages physically with mitochondria in infected host cells. These observations provide the first evidence that the T. cruzi amastigote flagellum is functional and likely plays a role in intracellular infection. With little basis to interrogate the functional capabilities of this understudied organelle, we launched a proteome discovery effort based on proximity-dependent biotinylation and profiling of T. cruzi amastigote flagellar proteins by mass spectrometry. Of the candidates emerging as significantly enriched in the amastigote flagellar biotinylome, membrane-associated and soluble proteins (ie. non-axonemal proteins) will be prioritized for further study. We will leverage this unique resource to validate flagellar localization of candidates in T. cruzi amastigotes and to generate and characterize loss-of-function mutants. We expect that our results will elucidate flagellar proteins that impact key aspects of the biology of intracellular T. cruzi amastigotes and establish the foundation for future mechanistic studies.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).