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Elucidating the Mechanistic Basis for Phagotrophy in the Protozoan Trypansoma cruzi

Award Number: R01GM144545
ORGANIZATION: NATIONAL INSTITUTE OF GENERAL MEDICAL SCIENCES
OPDIV: NIH
AWARD CLASS: DISCRETIONARY
AWARD ACTIVITY TYPE: SCIENTIFIC/HEALTH RESEARCH (INCLUDES SURVEYS)
PERIOD OF PERFORMANCE START DATE: 06/01/2022
PERIOD OF PERFORMANCE END DATE: 04/30/2026

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Elucidating the Mechanistic Basis for Phagotrophy in the Protozoan Trypansoma cruzi - PROJECT SUMMARY Whether its photons or fries eating is fundamental for life. From this basic principle, living organisms have evolved innumerable strategies to capture energy and nutrients from their environment, leading, in turn, to the incredible ecological diversity spanning the gamut from light eating photosynthetic autotrophs to predatory heterotrophs. As part of the world’s aquatic ecosystems, the expansive family of heterotrophic protozoan predators play a critical role in environmental carbon and nutrient cycling as they consume 75% of primary producing planktonic autotrophs daily. The vast majority of these flagellated phagotrophs use self-generated currents to funnel their prokaryotic prey into an ancient and highly enigmatic feeding apparatus prior to digestion. This feeding structure begins as a plasma membrane surface opening (cytostome), descends into an internal tubular invagination (cytopharynx) and ends with prey being enveloped within budding vesicles destined for lysosome fusion. Here we refer to this organelle as the cytostome/cytopharynx complex or SPC and, despite its near ubiquitous presence in protozoans, next to nothing is known mechanistically about how this structure is formed or functions. Intriguingly, a class of these phagotrophic predators known as the kinetoplastids, gave rise to a lineage of parasitic protozoa that can infect a wide variety of organisms ranging from plants to humans. Curiously, one species in particular, Trypanosoma cruzi, retained this ancestral organelle much like its free-living relatives (e.g. bodonids) and continues to use it as its primary route of endocytosis. Due to the fact that T. cruzi is easily culturable, genetically tractable and not reliant on SPC mediated endocytosis for viability in vitro, we have been able to conduct the first ever in-dept molecular analyses of this ubiquitous feeding organelle. Our initial published work on this structure described the first known proteins targeted to the SPC and was followed by a report on the identification of a family of SPC targeted myosin motors that we show contribute directly to the endocytic process. As a continuation of these studies, this proposal seeks to generate a holistic understanding of how SPC mediated endocytosis fundamentally functions. We will begin by dismantling the unified activity of endocytosis into its constituent processes; cargo capture through surface receptors (Aim1), receptor signal transduction and activation of endocytic machinery (Aim2) and finally active transport of phagocytosed cargo along the SPC for digestion (Aim3). Each of these aims will address important basic aspects of protozoan biology that continue to remain poorly understood. Critically, this proposal will combine both a broad approach to identify cytostomal surface receptors and SPC specific signaling components with a focused analysis of the role of the Act2 isoform in the endocytic process. By combining this model organism with a broad range of cutting-edge molecular tools and methodologies, we will be able to elucidate the mechanistic basis of this ancient protozoal feeding apparatus with the goal of providing insight into basic processes ranging from microbial food webs to parasitic diseases.


Issue Date FY	Funding FY	Legal Entity Name	Legal Entity Address	Legal Entity City	Legal Entity State	Legal Entity Zip Code	Legal Entity COUNTY	Legal Entity COUNTRY	Assistance Listing	Award Code	Budget Year	Action Date	Action Type	Action Amount

Issue Date FY: 2025 ( Subtotal = $302,000 )
2025	2025	UNIVERSITY OF GEORGIA RESEARCH FOUNDATION, INC.	310 E CAMPUS RD RM 409	ATHENS	GA	30602	CLARKE	USA	Biomedical Research and Research Training	000	4	4/30/2025	NON-COMPETING CONTINUATION	$302,000
														Subtotal = $302,000

Issue Date FY: 2024 ( Subtotal = $302,000 )
2024	2024	UNIVERSITY OF GEORGIA RESEARCH FOUNDATION, INC.	310 E CAMPUS RD RM 409	ATHENS	GA	30602	CLARKE	USA	Biomedical Research and Research Training	000	3	5/13/2024	NON-COMPETING CONTINUATION	$302,000
														Subtotal = $302,000

Issue Date FY: 2023 ( Subtotal = $502,000 )
2023	2023	UNIVERSITY OF GEORGIA RESEARCH FOUNDATION, INC.	310 EAST CAMPUS RD TUCKER HALL ROOM 409	ATHENS	GA	30602	CLARKE	USA	Biomedical Research and Research Training	001	2	7/25/2023	SUPPLEMENT FOR EXPANSION	$200,000
2023	2023	UNIVERSITY OF GEORGIA RESEARCH FOUNDATION, INC.	310 EAST CAMPUS RD TUCKER HALL ROOM 409	ATHENS	GA	30602	CLARKE	USA	Biomedical Research and Research Training	000	2	5/11/2023	NON-COMPETING CONTINUATION	$302,000
														Subtotal = $502,000

Issue Date FY: 2022 ( Subtotal = $302,000 )
2022	2022	UNIVERSITY OF GEORGIA RESEARCH FOUNDATION, INC.	310 EAST CAMPUS RD TUCKER HALL ROOM 409	ATHENS	GA	30602	CLARKE	USA	Biomedical Research and Research Training	000	1	5/30/2022	NEW	$302,000
														Subtotal = $302,000

Grand Total All Awards = $1,408,000

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Elucidating the Mechanistic Basis for Phagotrophy in the Protozoan Trypansoma cruzi

Award Number: R01GM144545

ORGANIZATION: NATIONAL INSTITUTE OF GENERAL MEDICAL SCIENCES

OPDIV: NIH

AWARD CLASS: DISCRETIONARY

AWARD ACTIVITY TYPE: SCIENTIFIC/HEALTH RESEARCH (INCLUDES SURVEYS)

PERIOD OF PERFORMANCE START DATE: 06/01/2022

PERIOD OF PERFORMANCE END DATE: 04/30/2026

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